JP2011076620A - Image generation system, program, and information storage medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image generation system capable of generating a real and good-looking image with a little processing load in the case of using particles to generate an image, a program and an information storage medium. <P>SOLUTION: A particle load reduction processing part 134 performs processing that changes at least one of the number of particle occurrence points, the number of particles and particle life on the basis of information about a processing load. It also performs depth queuing processing of a reference color of a particle set object on the basis of depth information of the particle occurrence points, and applies a depth queuing effect to each particle belonging to a particle set by using a base color. It also controls the number of partitions constituting a particle object on the basis of at least one of the depth information of the particle object, a positional relation to a virtual camera, and the ratio of a drawing area that occupies in a primitive picture constituting the particle object. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image generation system program and an information storage medium.

  Conventionally, a game system that generates an image that can be seen from a given viewpoint in an object space that is a virtual three-dimensional space is known, and is popular as a device that can experience so-called virtual reality.

JP 2000-242807 A

  Now, in such a game system, it is an important technical problem to generate a more realistic image in order to improve the player's virtual reality. Here, for example, when there is a splash generated in the game space, a realistic expression of the splash is important.

  A technique called a particle system is known as a technique for expressing such splashes. That is, some natural objects are useful when expressed as a collection of fine particles that are difficult to identify one by one. Examples include steam, fog, eruptions, earth smoke, shimmering flames, explosions, fountains and waterfalls, bubbles and splashes, fireworks, splashing powder, falling rain and snow, firewood, swirls and tornadoes, and cherry blossoms flying in the wind. can give.

  In the particle system, not only the shape is unstable but also a model of an object or phenomenon in which a clear surface does not exist is expressed as a movement of a large number of particles, and such particles are called particles.

  Here, particles have characteristics such as color and lifetime, and are generated, moved, and disappeared by a given rule (given by the emitter) and acting force (force). The position of the particle in each frame is determined by performing an operation for determining the position of the particle in the three-dimensional space such as fluid calculation, collision calculation, and motion calculation based on the emitter and force.

  When splashing or the like is expressed using such particles, a realistic image such as splashing can be generated.

  However, when an image such as splashing is generated using such particles, there is a drawback that the processing load becomes heavy.

  For example, it is preferable that the number of particles emitted per unit time is larger in order to generate a realistic and good-looking splash image. However, there is a problem that various processes necessary for image generation in which the number of particles increases increases.

  Especially in game systems that need to generate real-time images with limited hardware resources, the problem is how to generate real-looking images with less processing load when generating images using particles. Become.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to generate a real and good-looking image with a small processing load when generating an image using particles. An image generation system, a program, and an information storage medium are provided.

(1) The present invention is a system for generating an image,
A means for changing at least one of the number of particle generation points, the number of particles, and the lifetime of particles based on information on a processing load at the time of image generation;
Means for generating an image that is visible from a given viewpoint in the object space using particles;
It is characterized by including.

  A program according to the present invention is a program that can be used by a computer (a program embodied in an information storage medium or a carrier wave), and causes the computer to realize the above means. An information storage medium according to the present invention includes an information storage medium usable by a computer and a program for causing the computer to realize the above means.

  The information related to the processing load at the time of image generation is given as a given value by which the drawing speed per frame can be determined, such as a refresh rate, a global clock, or a CPU clock. Here, the processing load at the time of image generation may be a calculation load performed by the CPU or a calculation load generated by the drawing chip, and includes various processing loads necessary for image generation.

  The lifetime of the particles is given as, for example, particle characteristic information. For example, the life of the particles may be given in the form of an α value when performing translucent drawing.

  According to the present invention, when it is determined that the processing load is high, the processing load is reduced by reducing the number of particle generation points, the number of particles, or setting the particle life to be short. It is possible to prevent processing failures and the like.

(2) Further, an image generation system, a program, and an information storage medium according to the present invention are:
The number of particles is the number of particles existing on one screen or the number of particles generated from a given generation point.

(3) Further, an image generation system, a program, and an information storage medium according to the present invention are:
The processing load is reduced by preferentially shortening the lifetime based on the particles far from the virtual camera based on the depth information of the particles.

  By setting the particle life to be short, the particles can be quickly eliminated, so that the processing load can be reduced accordingly.

  Here, the farther away the particles, the less the influence of the appearance, so it is preferable to prioritize the particles far from the virtual camera and shorten the life based on the depth information of the particles.

  As described above, according to the present invention, it is possible to select a particle that has little effect on the appearance even if the lifetime is shortened based on the depth information of the particle, so that the effect of the appearance is kept at the maximum and the processing load is reduced. be able to.

(4) Further, an image generation system, a program, and an information storage medium according to the present invention are:
A processing load is reduced by preferentially excluding an image generation target from a set of particles generated from a particle generation point distant from the virtual camera based on depth information of the particle generation point.

  By excluding the particle set generated from the particle generation point from the image generation target, the processing load can be reduced accordingly.

  Particles generated from a particle generation point located far from the virtual camera based on the depth information of the particle generation point because the image effect of the particle generation generated from the particle generation point located far away is less affected by the appearance. It is preferable to preferentially exclude the image from the set.

  As described above, according to the present invention, based on the depth information of the particle, it is possible to select an image that has little visual influence even if it is not subject to image generation and exclude it from the subject of image generation. And the processing load can be reduced.

(5) An image generation system, a program, and an information storage medium according to the present invention include
The processing load is reduced by reducing the number of particles to be generated with priority from the particle generation point distant from the virtual camera based on the depth information of the particle generation point.

  By reducing the number of particles generated from the particle generation point, the processing load can be reduced accordingly.

  In this case, reducing the number of particles generated from a distant particle generation point has less visual effect, so it is generated with priority from the particle generation point far from the virtual camera based on the depth information of the particle generation point. It is preferable to reduce the number of particles.

  As described above, according to the present invention, it is possible to reduce the number of particles to be generated by selecting a particle that has little visual influence even when it is not an image generation target based on the depth information of the particle generation point. Can be kept at a maximum to reduce the processing load.

(6) An image generation system, a program, and an information storage medium according to the present invention are:
The processing load is reduced by lowering the precision of the object in preference to the object assigned to the particles away from the virtual camera based on the particle depth information.

  Decreasing the precision of an object is to make a model to be used simpler. According to the present invention, LOD (level of detail) can be performed on an object assigned to a particle based on the depth information of the particle, so that the visual effect can be kept at the maximum and the processing load can be reduced.

(7) An image generation system, a program, and an information storage medium according to the present invention include
The processing load is reduced by lowering the precision of the object in preference to the object assigned to the particle generated from the particle generation point remote from the virtual camera based on the depth information of the particle generation point.

  Decreasing the precision of an object is to make a model to be used simpler. According to the present invention, LOD (level of detail) can be performed on an object to be assigned to a particle based on the depth information of the particle generation point, so that the visual effect can be kept at the maximum and the processing load can be reduced.

(8) The present invention is a system for generating an image,
Means for excluding the particle or the object assigned to the particle from the target of image generation when the transparency given to the particle or the object assigned to the particle is smaller than a predetermined value;
Means for generating an image that is visible from a given viewpoint in the object space using particles;
It is characterized by including.

  A program according to the present invention is a program that can be used by a computer (a program embodied in an information storage medium or a carrier wave), and causes the computer to realize the above means. An information storage medium according to the present invention includes an information storage medium usable by a computer and a program for causing the computer to realize the above means.

  This is effective when the transparency given to a particle (or an object assigned to the particle) changes with the passage of time from the generation of the particle. Here, the transparency is given by, for example, an α value when performing the semi-transparent drawing process.

  When the transparency given to a particle or an object assigned to a particle becomes smaller than a predetermined value, the particle or the object assigned to the particle is excluded from the object of image generation, for example, a position for image generation It is possible to omit various processes relating to image generation, such as subsequent processing such as calculation processing, coordinate conversion processing, and drawing processing, thereby reducing the processing load.

(9) The present invention is a system for generating an image,
Means for performing the annihilation process of the particle or the object assigned to the particle when the height of the particle reaches a predetermined value;
Means for generating an image that is visible from a given viewpoint in the object space using particles;
It is characterized by including.

  A program according to the present invention is a program that can be used by a computer (a program embodied in an information storage medium or a carrier wave), and causes the computer to realize the above means. An information storage medium according to the present invention includes an information storage medium usable by a computer and a program for causing the computer to realize the above means.

  According to the present invention, for example, when the height of the splash generated using particles becomes the height of the water surface, or when the height of snow or the like generated using particles becomes the height of the ground, etc. And can eliminate snow.

  As described above, when the height of the particle reaches a predetermined value, by performing the annihilation process of the particle or the object assigned to the particle, the subsequent process regarding the particle can be omitted, so that the processing load can be reduced.

  In addition, since it can be determined whether or not the annihilation process is performed based on the height of the particles, the processing load required for the determination can be reduced. Therefore, this is effective when a state occurs in which the particle is outside the visible range depending on the height of the particle.

(10) An image generation system, a program, and an information storage medium according to the present invention include
The annihilation process includes a case where a particle or an object assigned to the particle annihilates after a predetermined time has elapsed.

(11) The present invention is a system for generating an image,
Based on the depth information of the particle, it is determined whether there is an object that blocks the field of vision in front of it, and when there is an object that blocks the field of view, the means to exclude the particle or the object assigned to the particle from the target of image generation,
Means for generating an image that is visible from a given viewpoint in the object space using particles;
It is characterized by including.

  A program according to the present invention is a program that can be used by a computer (a program embodied in an information storage medium or a carrier wave), and causes the computer to realize the above means. An information storage medium according to the present invention includes an information storage medium usable by a computer and a program for causing the computer to realize the above means.

  For example, when the splash is hidden by another object, the drawing process of the splash can be omitted, so that the processing load can be reduced.

(12) The present invention is a system for generating an image,
Means for performing depth cueing processing based on depth information of the particle generation point with respect to a reference color set for the particle set object represented by the particle set generated from the same particle generation point;
The color obtained by the depth cueing process is used as the base color of the particle set object, and the depth cueing effect is applied to each particle belonging to the particle set generated from the same particle generation point using the base color. Means for performing image generation processing;
It is characterized by including.

  A program according to the present invention is a program that can be used by a computer (a program embodied in an information storage medium or a carrier wave), and causes the computer to realize the above means. An information storage medium according to the present invention includes an information storage medium usable by a computer and a program for causing the computer to realize the above means.

  In general, when depth cueing processing is performed on a polygon object, the vertex color and the background color are combined for each vertex according to the depth value of the vertex, and the vertex color is changed according to the depth value. . For this reason, since the depth cueing process is required for each vertex of each particle object constituting the particle aggregate object, the processing load is remarkably increased.

  However, according to the present invention, depth cueing processing is performed based on the depth information of the particle generation point for the reference color set for the particle set object represented by the particle set generated from the same particle generation point. The color obtained by the above is used as the base color of the particle set object, and image generation processing is performed by applying the depth queuing effect to each particle belonging to the particle set generated from the same particle generation point using the base color. .

  For this reason, the calculation for obtaining the base color for one particle aggregate object is only required once. The FOG effect can be achieved with a processing load that is significantly smaller than when calculating vertex colors that change by depth cueing processing for all the vertices of each particle or particle object constituting the particle aggregate object.

(13) The present invention is a system for generating an image,
Means for controlling the number of divisions of the primitive constituting the particle object based on at least one of the depth information of the particle object, the positional relationship with the virtual camera, and the ratio of the drawing area in the screen of the primitive constituting the particle object;
Means for generating an image that is visible from a given viewpoint in the object space using particles;
It is characterized by including.

  A program according to the present invention is a program that can be used by a computer (a program embodied in an information storage medium or a carrier wave), and causes the computer to realize the above means. An information storage medium according to the present invention includes an information storage medium usable by a computer and a program for causing the computer to realize the above means.

  Here, the primitive is a polygon, a sprite, or the like.

  It is preferable to control so that the number of divisions of primitives constituting the particle object is increased when the depth information of the particle object or the distance from the virtual camera is increased.

  In general, when image generation is performed using hardware with limited memory resources, since the capacity of the real storage area of the VRAM (frame buffer) is limited, when trying to draw a large primitive in the VRAM (frame buffer) Paging occurs during the rendering of primitives, increasing the processing load and processing time.

  According to the present invention, when the depth information of the particle object or the distance from the virtual camera is increased, the number of divisions of the primitives constituting the particle object can be increased, and thus paging occurs during the rendering of the primitives. Can be prevented, and the processing load and processing time can be reduced.

(14) An image generation system, a program, and an information storage medium according to the present invention include
When the depth information of the particle object or the distance from the virtual camera is increased, the number of divisions of primitives constituting the particle object is increased.

(15) An image generation system, a program, and an information storage medium according to the present invention include
When the ratio of the drawing area to the screen of the primitives constituting the particle object increases, the number of divisions of the primitives constituting the particles is increased.

(16) An image generation system, a program, and an information storage medium according to the present invention include
The number of divisions is increased by subdividing the primitives assigned to the particles.

An example of the block diagram of the image generation system (game system) of this embodiment is shown. 2 shows an example of a game image generated by the image generation apparatus of the present embodiment. It is a flowchart figure for demonstrating the flow of the whole process at the time of producing | generating the image of a splash with the image production | generation apparatus of this Embodiment. It is a flowchart figure for demonstrating the flow of the whole process at the time of producing | generating the image of a splash with the image production | generation apparatus of this Embodiment. FIGS. 5A and 5B are diagrams for explaining how the drawing order is determined in units of particle generation points. FIGS. 6A, 6B, and 6C are diagrams for explaining the rendering order determination process based on the generation point of particles. FIGS. 7A, 7B, and 7C are diagrams for explaining the rendering order determination process based on the generation point of particles. FIGS. 8A and 8B are diagrams for explaining an example in which a sorting interval is set to determine the necessity of sorting processing. It is a flowchart for demonstrating an example of the flow of the drawing order determination process at the time of performing a translucent drawing process in this Embodiment. 10A, 10B, and 10C are diagrams for explaining a case where the drawing order is determined in units of primitives. FIGS. 11A, 11B, and 11C are diagrams for explaining a case where the drawing order is determined in units of primitives. FIGS. 12A and 12B are diagrams for explaining the case where the drawing order is determined in units of objects configured as a set of primitives. FIGS. 13A, 13B, and 13C are diagrams for explaining determination of the drawing order of objects. 14A, 14B, and 14C are diagrams for explaining determination of the drawing order of objects. It is a flowchart for demonstrating the other example of the flow of the drawing order determination process at the time of performing the translucent drawing process of this Embodiment. FIGS. 16A and 16B are diagrams for explaining the padding of particles. FIGS. 17A and 17B are diagrams for explaining an example of determining the position and size of a child particle. 18A and 18B are diagrams for explaining an example in which a particle object is assigned to a generated child particle. 19A and 19B are diagrams for explaining the temporal continuity of particles. FIG. 20 is a flowchart for explaining the flow of the padding process of particles. FIG. 21 is a flowchart for explaining an example of processing for reducing the processing load in the present embodiment. 22A and 22B are examples of images when the processing load is low and when the processing load is high. It is a flowchart for demonstrating the example which controls the number of particle generation points in consideration of depth information. 24A and 24B are schematic diagrams for explaining the number of particles when the processing load is low and when the processing load is high. It is a flowchart for demonstrating the example which controls the number of particles which generate | occur | produce from a particle generation point in consideration of depth information. It is a flowchart for demonstrating the flow of a process in the case of adjusting the particle generated from a particle generation point in consideration of depth information. FIG. 27A is a diagram schematically showing a state where the drawing process of the particles is omitted when the transparency given to the particles becomes a predetermined value or less, and FIG. It is the figure which represented typically a mode that the drawing process of a particle was abbreviate | omitted when it became below fixed. FIG. 6 is a flowchart for explaining a flow of processing in a case where particle drawing processing is omitted based on transparency and particle height given to particles. It is a figure for demonstrating the process reduction of a FOG effect. 30A, 30B, and 30C are diagrams for explaining the depth queuing process performed in this embodiment. It is a flowchart for demonstrating an example of the polygon division | segmentation of this Embodiment. It is a figure showing a mode that the sprite (plate polygon) which comprises a particle object is divided | segmented. It is a figure which shows an example of the structure of the hardware which can implement | achieve this embodiment. FIGS. 34A, 34B, and 34C are diagrams illustrating examples of various types of systems to which the present embodiment is applied.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

1. Configuration FIG. 1 shows an example of a block diagram of an image generation system (game system) of the present embodiment. In this figure, the present embodiment may include at least the processing unit 100 (or may include the processing unit 100 and the storage unit 170, or the processing unit 100, the storage unit 170, and the information storage medium 180), and other blocks. (For example, the operation unit 160, the display unit 190, the sound output unit 192, the portable information storage device 194, and the communication unit 196) can be arbitrary constituent elements.

  Here, the processing unit 100 performs various processing such as control of the entire system, instruction instruction to each block in the system, game processing, image processing, or sound processing, and functions thereof are various processors ( CPU, DSP, etc.) or hardware such as ASIC (gate array, etc.) or a given program (game program).

  The operation unit 160 is for a player to input operation data, and the function can be realized by hardware such as a lever, a button, and a housing.

  The storage unit 170 serves as a work area such as the processing unit 100 or the communication unit 196, and its function can be realized by hardware such as a RAM.

  An information storage medium (storage medium usable by a computer) 180 stores information such as programs and data, and functions thereof are an optical disk (CD, DVD), a magneto-optical disk (MO), a magnetic disk, and a hard disk. It can be realized by hardware such as a magnetic tape or a memory (ROM). The processing unit 100 performs various processes of the present invention (this embodiment) based on information stored in the information storage medium 180. That is, the information storage medium 180 stores information (program or data) for executing the means of the present invention (this embodiment) (particularly, the blocks included in the processing unit 100).

  Part or all of the information stored in the information storage medium 180 is transferred to the storage unit 170 when the system is powered on. Information stored in the information storage medium 180 includes program code, image data, sound data, display object shape data, table data, list data, and data for instructing the processing of the present invention. It includes at least one of information, information for performing processing according to the instruction, and the like.

  The display unit 190 outputs an image generated according to the present embodiment, and the function thereof can be realized by hardware such as a CRT, LCD, or HMD (head mounted display).

  The sound output unit 192 outputs the sound generated by the present embodiment, and its function can be realized by hardware such as a speaker.

  The portable information storage device 194 stores player personal data, save data, and the like. As the portable information storage device 194, a memory card, a portable game device, and the like can be considered.

  The communication unit 196 performs various controls for communicating with the outside (for example, a host device or other game system), and functions thereof are various processors, hardware such as a communication ASIC, It can be realized by a program.

  The program or data for executing the means of the present invention (this embodiment) may be distributed from the information storage medium of the host device (server) to the information storage medium 180 via the network and the communication unit 196. Good. Use of such an information storage medium of the host device (server) is also included in the scope of the present invention.

  The processing unit 100 includes a game processing unit 110, an image generation unit 120, and a sound generation unit 150.

  Here, the game processing unit 110 receives a coin (price) reception process, various mode setting processes, a game progress process, a selection screen setting process, a hit check process, a process for calculating a game result (results, results), and a plurality of processes. Various game processes such as a process for playing in a common game space or a game over process, operation data from the operation unit 160, personal data from the portable information storage device 194, stored data, Perform based on game programs.

  The image generation unit 120 performs various types of image processing in accordance with instructions from the game processing unit 110, for example, generates an image that can be viewed from a virtual camera (viewpoint) in the object space, and outputs the image to the display unit 190. .

  For example, the image generation unit 120 obtains the position and rotation angle (rotation angle around the X, Y, or Z axis) of the object (one or a plurality of primitive surfaces), moves the object (motion processing), and positions the viewpoint (virtual). Processing for obtaining the camera position) and line-of-sight angle (rotation angle of the virtual camera) and processing for arranging an object such as a map object in the object space are performed.

  Further, for example, the image generation unit 120 performs various geometric processes (three-dimensional) such as coordinate conversion from the local coordinate system to the world coordinate system, coordinate conversion from the world coordinate system to the viewpoint coordinate system, perspective conversion to the screen coordinate system, and clipping. (Operation). Then, drawing data (position coordinates, texture coordinates, color (luminance) data, or α value, etc. of definition points of a two-dimensional primitive surface) obtained by geometry processing is stored in the main memory 172 of the storage unit 170. Saved.

  In addition, for example, the image generation unit 120 performs the texture mapping, color (luminance) data interpolation processing, hidden surface removal, and the like based on the drawing data obtained by the geometry processing and stored in the main memory 172, and the primitive surface of the object. Is rendered in the frame buffer 174. As a result, an image at a given viewpoint (virtual camera) in the object space where the object is arranged is generated.

  Further, for example, the image generation unit 120 performs a process of sequentially generating, moving, or annihilating particles with time. More specifically, a process of randomly changing the generation amount, generation position, movement state (speed, acceleration, etc.) or lifetime of particles (virtual light source primitive) is performed. As a result, it is possible to realistically represent an irregularly shaped display object such as a splash.

  The image generation unit 120 includes at least one of a drawing order determination processing unit 130, a particle padding processing unit 132, and a particle load reduction processing unit 134.

  The drawing order determination processing unit 130 determines the necessity of a sorting process for determining the drawing order of a plurality of semi-transparent primitives based on a given condition, and if it is determined that the sorting process is necessary. Sorting a plurality of semi-transparent primitives, determining the drawing order of the plurality of semi-transparent primitives based on the processing result of the sorting process, and if it is determined that the sorting process is not necessary, based on the previous sorting process result A process for determining the drawing order of the semi-transparent primitives may be performed.

  In addition, the drawing order determination processing unit 130 determines the necessity of the sorting process for determining the drawing order of the plurality of semi-transparent primitive sets based on a given condition and the sorting process is necessary. In this case, sorting processing is performed in units of semi-transparent primitive sets based on the representative positions of the plurality of semi-transparent primitive sets, and the drawing order of the plurality of semi-transparent primitive sets is determined based on the processing result of the sorting process, so that sorting processing is not necessary. If it is determined that the drawing order of the semi-transparent primitive set is determined based on the previous sorting process result, the process may be performed.

  In addition, the drawing order determination processing unit 130 determines the necessity of the sorting process for determining the drawing order of the particle set object expressed by the particle set generated from a plurality of particle generation points based on a given condition, If it is determined that the sorting process is necessary, the sorting process of the particle aggregate object is performed based on the depth information of a plurality of particle generation points, and the drawing order of the particle aggregate object is determined based on the processing result of the sorting process. When it is determined that the processing is not necessary, a process of determining the drawing order of the particle aggregate object based on the processing result of the previous sorting process may be performed.

  Further, the drawing order determination processing unit 130 determines whether or not the predetermined condition is satisfied based on at least one of the position and rotation of the virtual camera.

  The drawing order determination processing unit 130 may determine whether or not the predetermined condition is satisfied based on at least one of the position and rotation of the character object.

  The drawing order determination processing unit 130 sets an area that requires sorting processing in advance, and satisfies the predetermined condition based on whether or not at least one of the virtual camera and the character object is in the area that requires sorting. You may make it judge whether it is too big.

  In the area that requires the sorting process, when at least one of the virtual camera and the character object moves in the area, the context of the plurality of semi-transparent primitives, the semi-transparent primitive set, or the generation point of the particles changes with respect to the virtual camera. It is preferable to make it a possible area.

  In addition, the area that needs to be sorted is displayed as a semi-transparent primitive, a semi-transparent primitive set, or an object represented by particles generated from a particle generation point when at least one of a virtual camera and a character object exists in the area. You may make it the area where the state which is not performed occurs.

  In addition, the drawing order determination processing unit 130 may perform sorting based on the depth information of the representative points of a plurality of semi-transparent primitive sets, and determine the drawing order for each semi-transparent primitive set.

  The drawing order determination processing unit 130 performs a process of sorting a plurality of particle aggregate objects expressed by a particle aggregate generated from a given generation point based on the depth information of the generation point and determining a drawing order of the particle aggregate object. You may make it perform.

  The particle padding processing unit 132 uses a particle given to the three-dimensional space as a parent particle, calculates a padding point coordinate generated based on the position coordinates of the parent particle, and generates a child particle at the padding point. You may make it perform.

  Further, the particle padding processing unit 132 calculates the coordinates of the padding point generated on the screen plane based on the position coordinates of the parent particle that is perspective-transformed to the screen plane, with the particle given to the three-dimensional space as the parent particle, You may make it perform the process which produces | generates a child particle in the padding point of the said screen plane.

  The child particles generated by adding water may take over the characteristic information of the parent particles.

  The particle padding processing unit 132 may determine the position of the padding point to be generated in consideration of the depth information of the parent particle.

  In addition, the particle padding processing unit 132 may determine the position of the padding point to be generated in consideration of information indicating the progress of time or frame.

  In addition, the particle padding processing unit 132 may control the number of child particles generated by padding in consideration of information indicating the progress of time or frame.

  Further, the particle padding processing unit 132 may determine the size of the object to be assigned to the child particle based on the depth information of the parent particle.

  In addition, the particle padding processing unit 132 may change the size of the object assigned to the child particles as time elapses or frames.

  In addition, the particle padding processing unit 132 determines that the given child particle generated in the (n + 1) th frame for the given parent particle has continuity with the given child particle generated in the nth frame for the same parent particle. You may make it perform the process produced | generated in the position which has.

The particle padding processing unit 132 also applies position information (x _n ′, f _y1 ) obtained by applying the functions f _x1 and f _y1 to the position information (x _n , y _n ) of a given parent particle in the nth frame. When the position of a given child particle in the n frame is determined based on y _n ′), the function f _{x1 is applied to} the position information (x _{n + 1} , y _{n + 1} ) of the same parent particle in the n + 1 frame. , F _y1 may be used to determine the position of a given child particle in the ( _{n + 1} ) th frame based on position information (x _{n + 1} ′, y _{n + 1} ′) obtained by applying f _y1 .

  Further, the particle padding processing unit 132 generates the first child particle and the second child when generating a plurality of child particles including the first child particle and the second child particle for the given parent particle. The generation position of the particles may be determined based on position information obtained by applying different functions.

  The particle padding processing unit 132 may control the number of child particles generated by padding in accordance with the depth information of the parent particle or the depth information of the particle generation point.

  Further, the particle padding processing unit 132 may control the number of child particles generated by padding based on the information regarding the processing load at the time of image generation.

  The particle load reduction processing unit 134 may perform a process of changing at least one of the number of particle generation points, the number of particles, and the lifetime of particles based on information regarding the processing load at the time of image generation.

  The number of particles may be the number of particles existing on one screen or the number of particles generated from a given generation point.

  Further, the particle load reduction processing unit 134 may reduce the processing load by shortening the lifetime in preference to particles away from the virtual camera based on the depth information of the particles.

  Further, the particle load reduction processing unit 134 reduces the processing load by excluding the image generation target from the particle set generated from the particle generation point away from the virtual camera based on the depth information of the particle generation point. You may do it.

  The particle load reduction processing unit 134 may reduce the processing load by reducing the number of particles to be generated with priority from the particle generation point away from the virtual camera based on the depth information of the particle generation point. .

  Further, the particle load reduction processing unit 134 may reduce the processing load by lowering the precision of an object in preference to an object assigned to a particle far from the virtual camera based on the depth information of the particle.

  Further, the particle load reduction processing unit 134 reduces the processing load by lowering the precision of the object in preference to the object assigned to the particle generated from the particle generation point away from the virtual camera based on the depth information of the particle generation point. You may do it.

  When the transparency given to a particle or an object assigned to the particle becomes smaller than a predetermined value, the particle load reduction processing unit 134 performs processing to exclude the particle or the object assigned to the particle from the target of image generation. You may do it.

  Further, the particle load reduction processing unit 134 may perform the annihilation process of the particle or the object assigned to the particle when the height of the particle reaches a predetermined value.

  The annihilation process preferably includes a case where a particle or an object assigned to the particle annihilates after a predetermined time has elapsed.

  Further, the particle load reduction processing unit 134 determines whether there is an object that blocks the field of vision based on the depth information of the particle, and when there is an object that blocks the field of view, generates an image of the particle or an object assigned to the particle. You may make it perform the process excluded from.

  The particle load reduction processing unit 134 performs depth cueing processing based on the depth information of the particle generation point with respect to the reference color set for the particle set object represented by the particle set generated from the same particle generation point. The color obtained by the depth cueing process is used as the base color of the particle set object, and the depth cueing effect is applied to each particle belonging to the particle set generated from the same particle generation point using the base color. You may do it.

  Further, the particle load reduction processing unit 134 determines the number of divisions of the primitives constituting the particle object based on at least one of the depth information of the particle object, the positional relationship with the virtual camera, and the ratio of the drawing area in the screen of the primitive constituting the particle object. You may make it perform the process to control.

  In addition, the particle load reduction processing unit 134 may increase the number of divisions of primitives constituting the particle object when the depth information of the particle object or the distance from the virtual camera increases.

  Further, the particle load reduction processing unit 134 may increase the number of divisions of the primitives constituting the particles when the ratio of the drawing area to the screen of the primitives constituting the particle object increases.

  The particle load reduction processing unit 134 may increase the number of divisions by re-dividing the primitives assigned to the particles.

  The sound generation unit 150 performs various types of sound processing in accordance with instructions from the game processing unit 110, generates a sound such as BGM, sound effect, or sound, and outputs the sound to the sound output unit 192.

  Note that all the functions of the game processing unit 110, the image generation unit 120, and the sound generation unit 150 may be realized by hardware, or all of them may be realized by a program. Alternatively, it may be realized by both hardware and a program.

  Note that the game system according to the present embodiment may be a system dedicated to the single player mode in which only one player can play, and not only such a single player mode but also a multiplayer mode in which a plurality of players can play. A system may be provided.

  Further, when a plurality of players play, game images and game sounds to be provided to the plurality of players may be generated using one terminal, or connected via a network (transmission line, communication line) or the like. Alternatively, it may be generated using a plurality of terminals.

2. Features of this Embodiment FIG. 2 shows an example of a game image generated by the image generation apparatus of this embodiment. In the present embodiment, a spray image as shown in the figure is generated using a particle system.

  Hereinafter, each feature of the present invention will be described with reference to an example in which the image generation apparatus of the present embodiment generates a splash image using a particle system.

(1) Process Flow FIGS. 3 and 4 are flowcharts for explaining the overall process flow when a splash image is generated by the image generation apparatus of the present embodiment.

  3 and 4 are processes performed by the image generation unit (130 in FIG. 1). Here, it is assumed that the image generation unit includes, for example, a CPU and a drawing unit (dedicated chip for image generation).

  Steps S10 to S30 in FIG. 3 are processes performed mainly by the CPU in units of particle generation points.

  First, a process for determining the drawing order for each occurrence point is performed based on the depth information of the occurrence points of the plurality of splashes (step S10). In this embodiment, since a semi-transparent object is assigned to the particles constituting the splash, it is necessary to draw semi-transparent in the frame buffer first from the generation point far from the virtual camera in order to draw accurately. For this reason, in the present embodiment, processing for determining the drawing order for each occurrence point is performed.

  In this embodiment, instead of unconditionally sorting a plurality of occurrence points for each frame, the necessity of the sorting process is determined based on the position of the character object (virtual camera) of each frame, When it is not necessary, the processing speed is increased by omitting the sorting process. (For details, see (2) Drawing Order Determination Processing).

  Next, various parameter setting processing is performed (step S20).

  For example, the process of determining the base color of each particle aggregate object for each generation point (see (5) FOG effect processing reduction for details), the process of determining the number of particles generated from each generation point, Processing for determining characteristics (particularly information on transparency and lifetime) (for details, see (4) Processing for reducing processing load) is performed.

  Then, based on the determined drawing order, the data of the back particle generation point is transferred to the drawing unit (step 30).

  Steps S40 to S90 in FIG. 4 are processes mainly performed by the vector unit for each particle.

  First, the transparency of the particles is reduced based on the frame number. If the transparency becomes negative, the process is terminated. Further, the size of the sprite (single polygon) assigned to the particles is enlarged based on the frame number (step S40).

  Next, based on the frame number, the position coordinates of the moving point of the particle moving in the three-dimensional space according to a given rule are calculated (step S50).

  Next, perspective transformation is performed on the position coordinates of the moved particles (this is used as a parent particle) and arranged on the screen plane (step S60).

  Next, a process of generating child particles around the parent particles after the perspective transformation is performed (step S70).

  Next, a sprite (one polygon) is assigned to the inflated child particle. At this time, polygon division is performed according to the distance from the generation point and the virtual camera (step S80).

  Next, a color and texture coordinate coordinates are added to the obtained sprite polygon to generate a packet and draw it (step S90).

(2) Drawing Order Determination Process First, a drawing order determination process that is performed when a splash image is generated in the present embodiment will be described.

  In general, the rendering order when performing translucent rendering processing is determined in units of primitives, for example, in the case of polygon objects, in units of polygons. In this embodiment, the rendering order is determined for each particle generation point. .

  FIGS. 5A and 5B are diagrams for explaining how the drawing order is determined in units of particle generation points.

  FIG. 5A shows the positional relationship between the virtual camera and the generation points H1 to H4. M1 to M4 schematically show splashes (particle aggregate objects) expressed by particles generated from the generation points H1 to H4.

  In this embodiment, sorting processing necessary for translucent drawing is performed in units of particle generation points. For example, in the case of FIG. 5A, the front-rear relationship of the generation points H1 to H4 when viewed from the virtual camera 210 is H4, H3, H2, and H1 in order from the back (see FIG. 5B). Therefore, when each of the splashes M1 to M4 is subjected to the α blending process and rendered translucently in the frame buffer 220, the spray is performed in the order of the spray in the order of M4, M3, M2, and M1 in the order of the depth based on the depth information of the occurrence point. To do.

  For example, the object OP3 assigned to the particles generated from the generation point H3 is drawn after the object OP4 allocated to the particles generated from the generation point H4.

  As described above, in this embodiment, a plurality of particle generation points are sorted based on the depth information, and the drawing order is determined for each generation point. Then, according to the determined drawing order, the semi-transparent drawing process of the semi-transparent primitive assigned to the particles generated from the plurality of particle generation points is performed.

  As a result, translucent primitives assigned to particles generated from an occurrence point with a higher drawing order (located deeper) are translucent assigned to particles generated from an occurrence point with a lower drawing order (positioned closer) A translucent drawing process can be performed prior to the primitive.

  In this way, the processing load can be greatly reduced as compared with the case where the drawing order is determined by sorting for each particle.

  FIGS. 6A, 6B, 7C, and 7A, 7B, and 7C are diagrams for explaining the drawing order determination process based on the generation point of particles.

  6A and 7A show the positional relationship between the virtual camera and the generation point of the particles before and after the movement of the virtual camera. M1 to M4 schematically show splashes (particle aggregate objects) expressed by particles generated from the generation points H1 to H4. 210-1 is a virtual camera before movement, and 210-2 is a virtual camera after movement.

  For example, in the case of FIG. 6A, the front-rear relationship of the particle generation points H1 to H4 when viewed from the virtual camera 210-1 is H4, H3, H2, and H1 in order from the back (FIG. 6B). reference).

  Further, the front-rear relations of the translucent polygons H1 to H4 when viewed from the virtual camera 210-2 are H3, H1, H2, and H4 in order from the back (see FIG. 6C).

  As described above, when the depth relationship between the generation point and the virtual camera is displaced due to the change in the positional relationship between the generation point and the virtual camera, a sorting process is required.

  However, in the case of FIG. 7A, for example, the front-rear relationship of the particle generation points H1 to H4 when viewed from the virtual camera 210′-1 is H4, H3, H2, and H1 in order from the back (FIG. 7B )), The front-rear relationship of the particle generation points H1 to H4 when viewed from the virtual camera 210′-2 is also H4, H3, H2, and H1 in order from the back (see FIG. 7C). Therefore, when the virtual camera moves as shown in FIG. 7A, when drawing an image viewed from the virtual camera 210′-2, the virtual camera 210′-1 does not need to be sorted again. The result of sorting performed when drawing an image viewed from the above can be used.

  Therefore, in the present embodiment, the necessity of the sorting process for determining the drawing order of the particle aggregate object expressed by the particle aggregate generated from a plurality of particle generation points based on a given condition is necessary, and the sorting process is necessary. If it is determined, the sorting process of the particle aggregate object is performed based on the depth information of the plurality of particle generation points, the drawing order of the particle aggregate object is determined based on the processing result of the sorting process, and the sorting process is not necessary. When it is determined that the drawing order of the particle aggregate object is determined based on the processing result of the previous sorting process.

  FIGS. 8A and 8B are diagrams for explaining an example in which a sorting interval is set to determine the necessity of sorting processing.

  In FIG. 8A, reference numeral 230 denotes a player character, and reference numeral 240 denotes a road provided in the game space as a moving route of the player character. The player character 230 travels on a predetermined moving route 240 (a road provided in the game space), and the virtual camera is configured to follow the player character 230.

  H1 to H4 are points where splashing occurs, and M1 to M4 schematically show the range of the splashing (particle aggregate object) expressed by the particles generated from the generating points H1 to H4.

  Reference numeral 250-1 denotes a sorting section provided on the moving route. As shown in FIG. 8A, a section where the road is largely curved is set as a sorting section 250-1. This is because, when the splashes M1 to M4 are viewed from the virtual camera moving in such a section, the depth relationship of the splashes with respect to the virtual camera may change as described with reference to FIGS.

  As described above, in this embodiment, when the virtual camera moves, an area where the front-to-back relationship with respect to the virtual camera at the occurrence point of the splash (particle aggregate object) may be specified as the sorting section.

  Then, if the position of the player character 230 is within the sorting section in each frame, it is determined that the sorting process is necessary. If the position of the player character 230 is not within the sorting section, the spraying point is sorted. Judged that there is no need for processing.

  For example, the sorting section 250-1 can be specified by a route from the start point. A player character traveling on a predetermined moving route 240 (a road provided in the game space) also has a road value as a current position from the start point. Therefore, for example, when (2000 to 2050) is set as the sorting section 250-1, if the path value x of the current position of the player character is 2000 <x <2050, it is determined that the sorting process is necessary. Is done.

  In this way, when the player character is located outside the sorting section, the sorting process can be omitted, so that the processing load can be reduced.

  The sorting section 250-2 in FIG. 8B is set to a section where the field of view is blocked by the rock object 260 on the moving route 240 and the splash is not visible. That is, while the player character is moving in the sorting section 250-2, the image captured by the virtual camera following the player character is blocked by the rock object 260, and the splashes M1 to M4 do not move.

  As described above, in the present embodiment, by setting an area where the state in which the splash is not displayed is set as the sorting section, it is possible to prevent flickering due to a change in the drawing order accompanying the sorting process.

  FIG. 9 is a flowchart for explaining an example of the flow of the drawing order determination process when the translucent drawing process is performed in the present embodiment.

  First, the necessity of the sorting process is determined based on whether or not the character object or the virtual camera is in an area that requires sorting (step S110).

  When the character object or the virtual camera is in an area where sorting is necessary, sorting processing is performed in units of particle generation points based on depth information of a plurality of particle generation points, and the drawing order is determined in units of particle generation points ( Step S120).

  If the character object or the virtual camera is not in the area where sorting is necessary, the drawing order is determined for each particle generation point based on the processing result of the previous sorting process (step S130).

  Next, in accordance with the determined drawing order, translucent drawing processing is performed on the particle aggregate object generated from a plurality of particle generation points (step S140).

  In FIGS. 8A, 8B, and 9, the case where the sorting interval is set and the necessity of the sorting process is determined has been described as an example. However, the present invention is not limited to this. For example, the necessity of the sorting process may be determined based on whether or not the change in the placement of the virtual camera is within a predetermined range.

  In the above-described embodiment, the case where the drawing order is determined in units of particle generation points for expressing the splash when the splash is drawn translucently is described as an example, but the present invention is not limited thereto.

  For example, the drawing order may be determined in units of primitives when performing the translucent drawing process.

  10A, 10B, 11C, and 11A, 11B, and 11C are diagrams for explaining the case where the drawing order is determined in units of primitives. Here, the primitive is, for example, a polygon or a sprite.

  FIGS. 10A and 11A show the positional relationship between the virtual camera and the primitive before and after the movement of the virtual camera. P1 to P4 are assumed to be translucent polygons, for example. 210-1 is a virtual camera before movement, and 210-2 is a virtual camera after movement.

  For example, in the case of FIG. 10A, the front-rear relations of the translucent polygons P1 to P4 when viewed from the virtual camera 210-1 are P4, P3, P2, and P1 in order from the back (see FIG. 10B). ).

  Further, the front-rear relations of the translucent polygons P1 to P4 when viewed from the virtual camera 210-2 are P3, P1, P2, and P4 in this order (see FIG. 10C).

  As described above, when the depth relationship of the translucent polygon with respect to the virtual camera is displaced due to a change in the positional relationship between the translucent polygon and the virtual camera, a sorting process is required.

  However, in the case of FIG. 11A, for example, the front-rear relationship of P1 to P4 of the translucent polygons when viewed from the virtual camera 210′-1 is P4, P3, P2, and P1 in order from the back (FIG. 11B )), The front-rear relationship of P1 to P4 of the translucent polygons when viewed from the virtual camera 210'-2 is also P4, P3, P2, and P1 sequentially from the back (see FIG. 11C). Therefore, when the virtual camera moves as shown in FIG. 11A, when rendering an image viewed from the virtual camera 210′-2, the virtual camera 210′-1 does not need to be sorted again. The result of sorting performed when drawing an image viewed from the above can be used.

  Therefore, the necessity of the sorting process for determining the drawing order of a plurality of translucent primitives based on a given condition is judged, and when the sorting process is judged to be necessary, the sorting process of a plurality of translucent primitives is performed. Determine the drawing order of multiple translucent primitives based on the processing result of the sorting process, and if it is determined that sorting is not necessary, determine the drawing order of semitransparent primitives based on the previous sorting process result You may make it do.

  FIGS. 12A and 12B are diagrams for explaining the case where the drawing order is determined in units of objects configured as a set of primitives.

  FIG. 12A shows the positional relationship between the virtual camera and the translucent objects O1 to O4. P31 and P32 are semi-transparent polygons belonging to the semi-transparent object O3. Further, it is assumed that P41 and P42 are translucent polygons belonging to the translucent object O4.

  In such a case, in this embodiment, the sorting process is performed in units of objects. For example, in the case of FIG. 12A, the front-rear relationship of the translucent objects O1 to O4 when viewed from the virtual camera 210-1 is O4, O3, O2, and O1 in order from the back (see FIG. 12B). ). Accordingly, when the objects O1 to O4 are subjected to the α blending process and rendered translucently in the frame buffer 220, the objects are rendered in the order of O4, O3, O2, and O1 in the order of the object.

  That is, the polygons P31 and P32 belonging to the object O3 are drawn after the polygons P41 and P42 belonging to the object O4.

  FIGS. 13A, 13B, and 14C, and FIGS. 14A, 14B, and 14C are diagrams for explaining determination of the drawing order of objects.

  FIGS. 13A and 14A show the positional relationship with the object before and after the movement of the virtual camera. Assume that O1 to O4 are translucent objects, for example. 210-1 is a virtual camera before movement, and 210-2 is a virtual camera after movement.

  For example, in the case of FIG. 13A, the front-rear relationship of the translucent objects O1 to O4 when viewed from the virtual camera 210-1 is O4, O3, O2, and O1 in order from the back (see FIG. 13B). ).

  Further, the front-rear relations of the translucent polygons O1 to O4 when viewed from the virtual camera 210-2 are O3, O1, O2, and O4 in order from the back (see FIG. 13C).

  Thus, when the depth relationship of the object with respect to the virtual camera is displaced due to a change in the positional relationship between the object and the virtual camera, a sorting process is required.

  However, in the case of FIG. 14A, for example, the front-rear relationship of the objects O1 to O4 when viewed from the virtual camera 210′-1 is O4, O3, O2, and O1 in order from the back (see FIG. 14B). The front-rear relationship of the objects O1 to O4 when viewed from the virtual camera 210′-2 is also O4, O3, O2, and O1 in order from the back (see FIG. 14C). Therefore, when the virtual camera moves as shown in FIG. 14A, when drawing an image viewed from the virtual camera 210′-2, the virtual camera 210′-1 does not need to be sorted again. The result of sorting performed when drawing an image viewed from the above can be used.

  Therefore, in this embodiment, the necessity of the sorting process for determining the drawing order of a plurality of semi-transparent primitive sets (objects) is determined based on a given condition, and it is determined that the sorting process is necessary. In this case, sorting processing is performed in units of semi-transparent primitive sets based on the representative positions of the plurality of semi-transparent primitive sets (objects), and the drawing order of the plurality of semi-transparent primitive sets (objects) is determined based on the processing result of the sorting process. If it is determined that the sorting process is not necessary, a process of determining the drawing order of the semi-transparent primitive set (object) based on the previous sorting process result is performed.

  FIG. 15 is a flowchart for explaining another example of the flow of the drawing order determination process when the translucent drawing process of the present embodiment is performed.

  First, the necessity of the sorting process is determined based on whether or not the change in the placement of the virtual camera is within a predetermined range (step S210). Here, the change in the placement of the virtual camera is, for example, a change in the position or orientation (rotation) of the virtual camera.

  If the change in the placement of the virtual camera is within the predetermined range, the object sorting process is performed based on the depth information, and the drawing order is determined for each object (step S220).

  On the other hand, if the change in the placement of the virtual camera is not within the predetermined range, the drawing order is determined for each object based on the processing result of the previous sorting process (step S230).

  Next, in accordance with the determined rendering order, a semi-transparent rendering process for the primitives constituting the object is performed (step S240).

(3) Particle Inflating Process Next, a particle inflating process performed when a splash image is generated in the present embodiment will be described.

  FIGS. 16A and 16B are diagrams for explaining the padding of particles.

  PP1 to PP4 in FIG. 16A are particles generated in a given frame using an existing particle system. Each particle has characteristics such as color and life, and is generated, moved, and disappeared by a given rule (given by the emitter) and acting force (force). The particles PP1 to PP4 in each frame The position is determined by performing operations for determining the position of the particle in the three-dimensional space, such as fluid calculation, collision calculation, and motion calculation based on the emitter and force.

  Here, it is preferable to generate more particles in order to create a realistic and good-looking splash. However, in order to generate particles using an existing particle system, the calculation is required for each particle. Therefore, when the number of particles to be generated increases, the calculation amount increases accordingly.

  Therefore, in the present embodiment, as shown in FIG. 16B, the particles PP1 to PP4 given to the three-dimensional space are used as parent particles, and based on the position coordinates of the parent particles PP1 to PP4 that are perspective-transformed to the screen plane. Child particles CP11 to CP44 are generated at the padding points generated on the screen plane.

  The child particles CP11 to CP14 are generated by padding from the parent particle PP1, the child particles CP21 to CP24 are generated by padding from the parent particle PP2, and the child particles CP31 to CP34 are padded from the parent particle PP3. The child particles CP41 to CP44 are generated by adding water from the parent particle PP4.

  In this way, since it is possible to omit the calculation process until the position of the child particle is determined in the three-dimensional space using the existing particle system, it is possible to generate a splash image having a volume with a small amount of calculation. become.

  FIGS. 17A and 17B are diagrams for explaining an example of determining the position and size of a child particle.

  PP1 (X1, Y1) in FIG. 17A is a position coordinate of a particle (this is referred to as a parent particle) that is perspective-transformed to the screen plane 310 in the nth frame.

  In the present embodiment, the coordinates of the padding point generated on the screen plane are calculated based on the position coordinates of the parent particle PP1 that is perspective-transformed to the screen plane, and child particles are generated at the padding point.

  Here, when the coordinates of the first padding point M11 are (x11, y11) and the coordinates of the second padding point M12 are (x12, y12), x11, y11, x12, y12 are obtained as follows. .

x11 = X1 + f (S, t, random number 1) (1)
y11 = Y1 + f (S, t, random number 1) (2)
x12 = X2 + f (S, t, random number 2) (3)
y12 = Y2 + f (S, t, random number 2) (4)
The coordinates (x11, y11) of the first inflated point M11 and the coordinates (x12, y12) of the second inflated point M12 thus obtained are the generation positions of the child particles CP11, CP12. That is, (x11, y11) and (x12, y12) are the position coordinates of the child particles CP11 and CP12.

  Here, S is a value representing a magnification or the like given in relation to the depth value z, and t is a frame number. If the distances from the parent particle PP1 to the child particles CP11 and CP12 are, for example, l1 and l2, the distance l1 away from the parent particle according to the depth value and the frame number is obtained by using (1) to (4). Child particles CP11 and CP12 can be generated in l2.

  Random numbers 1 and 2 represent the positions in the random number sequence of the random numbers to be used. In a plurality of consecutive frames, random number 1 is always used for the first child particle and random number 2 is always used for the second child particle. By doing so, the trajectory of the child particles can be made continuous in a plurality of consecutive frames.

  FIG. 17B is a diagram for explaining a generation example of child particles when the depth value of the parent particle is z = 100 at the time of perspective transformation.

  Here, CP′11 (x11 ′, y11 ′) and CP′12 (x′12, y′12) are set as the parent particle position coordinates PP1 (X1, X2) when the depth value of the parent particle is z = 100. It is assumed that the position coordinates of the child particles CP′11 and CP′12 generated on the screen plane 310 based on Y1). At this time, as shown in FIG. 17B, the position of the child particles is generated closer to the parent particle than in the case of FIG.

  That is, if the distances from the parent particle PP1 to the child particles CP′11 and CP′12 are l′ 1 and l′ 2, for example, l′ 1 <l1 and l′ 2 <l2.

  As described above, in this embodiment, when the depth value (z value) of the parent particle is large (when the parent particle is located away from the virtual camera), a child particle is generated at a close position, and the depth value of the parent particle is obtained. When (z value) is small (when the parent particle is close to the virtual camera), a child particle is generated at a distant position. Therefore, a child particle can be generated at a position having a natural perspective according to the depth value (z value) of the parent particle.

  Further, in this embodiment, as the frame number increases (as the time after the generation of particles increases), child particles are generated at positions away from the parent particles. By doing so, it is possible to express how the splashes spread as time passes.

  18A and 18B are diagrams for explaining an example in which a particle object is assigned to a generated child particle.

  FIG. 18A shows a state in which the sprite 350 is assigned as a particle object to the child particle CP. Since the sprite can be generated by giving two vertices SV1 and SV2, the positions of the two vertices SV1 and SV2 around the child particle CP are determined based on the size of the sprite 350 determined according to the depth value of the parent particle. decide.

  Here, when the movement distance from the child particle CP to the two vertices SV1 and SV2 of the sprite is r1, the following expression is given.

r1 = local particle size x S
Here, the local particle size represents the size of the particle object assigned to the particle in the local coordinate system. By obtaining r1 as the movement distance in this manner, the size of the sprite assigned to the child particle can be reduced as the depth value (z value) of the parent particle increases (as the parent particle moves away from the virtual camera). . Therefore, sprites having a natural perspective relationship can be assigned to the child particles according to the depth value (z value) of the parent particle.

  When the sprite 350 is given as a particle object to the child particle CP, the position of the child particle CP may be determined as the vertex SV1 of one of the sprite 350, and the position of another vertex SV2 may be determined around the child particle CP. . In this way, since the calculation for determining the position of one vertex SV1 of the sprite 350 can be omitted, the processing load can be reduced.

  FIG. 18B shows a state in which a polygon object 360 is assigned as a particle object to the child particle CP. Since the polygon object 360 can be generated by giving eight vertices of PV1 to PV8, eight vertices PV1 to PV8 around the child particle CP based on the size of the polygon object determined according to the depth value of the parent particle. Determine the position.

  Here, when the moving distance from the child particle to the eight vertices PV1 to PV8 of the polygon object is r2, the following equation is given.

r2 = local particle size x S
Here, the local particle size represents the size of the particle object assigned to the particle in the local coordinate system. By obtaining r2 as the movement distance in this manner, the size of the polygon object assigned to the child particle can be reduced as the depth value (z value) of the parent particle increases (as the parent particle moves away from the virtual camera). it can. Therefore, a polygon object having a natural perspective relationship can be assigned to a child particle according to the depth value (z value) of the parent particle.

  19A and 19B are diagrams for explaining the temporal continuity of particles. FIG. 19A schematically shows the state of parent particles and child particles at t = 1 to t = 6. Here, t is a parameter representing the passage of time, for example, a frame number or the like.

  Here, the positions of the parent particles of the screen planes 310-1, 310-1,... At t = 1, 2... Are PPt1, PPt2,..., And the positions of the first child particles are CP1t1, CP1t2,. The positions are CP2t1, CP2t2,.

  As shown in the figure, in the present embodiment, a child particle generated at the (n + 1) th frame for a given parent particle is continuity with a given child particle generated at the nth frame for the same parent particle. Is generated at a position having

  In the present embodiment, for example, the positions of the first child particles at t = 1, 2,... Are generated using the first trajectory function 370 (see FIG. 19B) consisting of h = f1 (t). The positions of the second child particles at t = 1, 2,... Are generated using a second trajectory function 380 (see FIG. 19B) consisting of h = f2 (t). By doing so, it is possible to cause the first child particle and the second child particle to draw a continuous trajectory in the preceding and following frames.

  FIG. 20 is a flowchart for explaining the flow of the padding process of particles.

  First, particles of the frame are generated in a three-dimensional space using a given particle system (step S310). Each particle has characteristics such as color and life given by a given particle system and determines its position in 3D space based on a given rule (given by the emitter) and acting force (force) It is generated by performing an operation.

  Next, the particles in the three-dimensional space are perspective-transformed to the screen plane (step S320).

  Next, using the particles on the screen plane as the parent particles, the coordinates of the padding point are calculated based on the position of the parent particles (step S330). For example, the position coordinates of the padding point may be calculated by the method described with reference to FIGS.

  Next, a child particle is generated at the padding point (step S340). Here, the child particle takes over the characteristic information such as the color and life of the parent particle.

  Next, a particle object is assigned to the child particle (step S350). As described in FIGS. 18A and 18B, a sprite or a polygon object can be assigned as a particle object. For example, by using a sprite polygon with a translucent texture, a realistic splash image can be generated.

  In the above embodiment, the case where a sprite or a polygon object is assigned as a particle object to a child particle has been described as an example, but the present invention is not limited to this. For example, a free-form surface control point or another primitive may be assigned.

(4) Processing for Reducing Processing Load FIG. 21 is a flowchart for explaining an example of processing for reducing processing load in the present embodiment.

  First, the processing load at the time of image generation is monitored, and processing load information is acquired (step 410). Here, the processing load information is given by, for example, a drawing rate per frame given by a refresh rate, a global clock, a CPU clock, or the like.

  When the processing load is high, parameters for controlling at least one of the number of particle generation points, the number of particles, and the lifetime of particles are adjusted (steps S420 and S430). Whether or not the processing load is high is determined based on the processing load information.

  Next, an example in which the number of particle generation points is controlled in consideration of depth information will be described.

  22A and 22B are examples of images when the processing load is low and when the processing load is high. In this embodiment, when the processing load is low, a large number of splashes generated on a rock or the like are generated (see FIG. 22A). However, when it is determined that the processing load is high based on the processing load information, the distant spray is excluded from image generation. That is, the processing load is reduced by not generating a splash image marked with an X in FIG. 22B or adjusting the parameter value. Whether it is far away is determined based on the depth information of the splashing occurrence point. In this way, for the splashes with X marks, a series of image generation processing from particle generation processing necessary for image generation to drawing processing can be omitted, so that the processing load can be reduced.

  FIG. 23 is a flowchart for explaining an example of controlling the number of particle generation points in consideration of depth information.

  First, the processing load at the time of image generation is monitored, and processing load information is acquired (step S510). Here, the processing load information is given by, for example, a drawing rate per frame given by a refresh rate, a global clock, a CPU clock, or the like.

  When the processing load is high, the depth information of the particle generation point is acquired, and the particle set object expressed by the particle set generated from the particle generation point away from the virtual camera is prioritized based on the depth information of the particle generation point Thus, the image is generated. (Steps S520, 530, 540).

  Next, an example of adjusting the number of particles generated from a particle generation point with depth information taken into account will be described.

  24A and 24B are schematic diagrams for explaining the number of particles when the processing load is low and when the processing load is high. In FIG. 24A, reference numeral 410 denotes a particle aggregate object that represents splashes, and reference numeral 412 denotes a particle object that constitutes the particle aggregate object.

  In this embodiment, when the processing load is low, a large number of particles are generated from the particle generation point, and as a result, a large number of particle object images are generated (see FIG. 24A).

  However, if the processing load information determines that the processing load is high, the number of particles generated from a distant particle generation point is reduced.

  Reference numeral 410 ′ in FIG. 24B denotes a particle aggregate object that represents a splash expressed by particles generated from a distant generation point when the processing load is high. Whether it is far away is determined based on the depth information of the splashing occurrence point. Since 410 'reduces the number of particles to be generated as compared with 410, an image of a particle object that is smaller than 410 is generated (see FIG. 24B).

  FIG. 25 is a flowchart for explaining an example of controlling the number of particles generated from a particle generation point in consideration of depth information.

  First, the processing load at the time of image generation is monitored, and processing load information is acquired (step 610). Here, the processing load information is given by, for example, a drawing rate per frame given by a refresh rate, a global clock, a CPU clock, or the like.

  When the processing load is high, the depth information of the particle generation point is acquired, and the number of particles generated with priority from the particle generation point away from the virtual camera is reduced based on the depth information of the particle generation point. (Steps S620, 630, and 640). The process of reducing the number of particles is, for example, a process of changing a parameter value for controlling the number of particles to be generated.

  FIG. 26 is a flowchart for explaining the flow of processing when adjusting the particles to be generated from the particle generation point in consideration of the depth information.

  First, the processing load at the time of image generation is monitored, and processing load information is acquired (step 710). Here, the processing load information is given by, for example, a drawing rate per frame given by a refresh rate, a global clock, a CPU clock, or the like.

  If the processing load is high, the depth information of the particles is acquired, and based on the depth information of the particles, processing is performed to shorten the life in preference to the particles far from the virtual camera (steps S720, 730, and 740). . For example, the particle sorting process may be performed based on the depth information, and the lifetime of the particles may be set to be short by a predetermined number from the far side.

  Next, a case where the drawing process of particles is omitted based on the transparency and the height of the particles given to the particles will be described.

  FIG. 27A is a diagram schematically showing a state where the drawing process of the particles is omitted when the transparency given to the particles becomes a predetermined value or less, and FIG. It is the figure which represented typically a mode that the drawing process of a particle was abbreviate | omitted when it became below fixed.

  Pt1, Pt2, and Pt3 in FIG. 27A are diagrams showing temporal changes of particles generated from a given particle generation point. Here, the particles have transparency information (α value) as characteristic information, and the transparency information (α value) is controlled to decrease with time. For example, α = 128 for Pt1, α = 52 for Pt2, and α = 0 for Pt3.

  The transparency information (α value) is used when a particle or a particle object assigned to the particle is subjected to α blending processing or the like to perform translucent rendering. Here, for example, when the α value is 0, even if the particle or the particle object assigned to the particle is rendered translucently, it is not displayed transparently.

  Therefore, in the present embodiment, when the transparency information (α value) given as the particle characteristic information becomes 0 or less, the particle is excluded from the target of image generation, and subsequent image generation processing related to the particle is performed. Is omitted.

  In the above-described embodiment, when the transparency information (α value) given as the particle characteristic information is 0 or less, the particle is excluded from the image generation target, and the subsequent image generation processing regarding the particle is omitted. However, the present invention is not limited to this. For example, when the transparency information (α value) given as the particle characteristic information reaches a predetermined value, the particle may be excluded from the image generation target, and the subsequent image generation processing regarding the particle may be omitted. .

  P't1, P't2, and P't3 in FIG. 27B represent changes in the temporal height of particles generated from a given particle generation point. 510 is the height of the reference plane. Here, the reference plane is, for example, the water surface or the ground. In the present embodiment, the height of the sea surface is defined as the height of the reference surface, and when the height of the generated particle is equal to or lower than the height of the reference surface, the particle is excluded from the image generation target, Image generation processing related to the particles is omitted.

  FIG. 28 is a flowchart for explaining the flow of processing when the particle drawing processing is omitted based on the transparency and particle height given to the particles.

  Steps S810 to S860 are processes performed for each frame from the generation of a given particle to the disappearance, and the particle termination process of S870 is a process performed when the particle disappears.

  First, the transparency of particles in the frame is calculated (step 810).

  Next, when the transparency of the particle is 0 or less, a particle termination process is performed to make the particle disappear (steps S820 and S870).

  If the transparency of the particle is not less than 0, the movement of the particle is calculated to obtain the particle position in the frame (steps S820 and S830). In the particle movement calculation, for example, the position of the particle in each frame is determined by performing an operation for determining the position of the particle in the three-dimensional space, such as fluid calculation, collision calculation, and motion calculation based on the emitter and force.

  Next, when the obtained value regarding the height of the position becomes a predetermined value, a particle termination process for annihilating the particle is performed (steps S840 and S870).

  If the calculated value regarding the height of the position is not a predetermined value, drawing processing using particles is performed (steps S840 and S850).

  When processing the next frame, the processing of steps S810 to S860 is repeated again (step S860).

(5) Reduction of processing of FOG effect For example, when the FOG effect is produced as in the case of realistically expressing the state in which an object such as splashing is blended into the background according to the distance from the virtual camera, the depth cueing process is performed. I do. For example, when depth cueing processing is performed on a polygon object, the vertex color and the background color are combined for each vertex according to the depth value of the vertex, and the vertex color is changed according to the depth value. .

  In the present embodiment, a particle object is assigned to a large number of particles generated from one particle generation point, such as splashing, and is generated as a set of these particle objects (particle set object).

  Therefore, in order to produce the FOG effect against the splash, a depth cueing process is required for each vertex of each particle object constituting the particle aggregate object, so that the processing load is remarkably increased.

  Therefore, in the present embodiment, the following processing is performed in order to produce the FOG effect with a small processing load.

  FIG. 29 is a diagram for explaining processing reduction of the FOG effect.

  Reference numeral 610 denotes a first particle set object for expressing splashes, and is configured as a set of particle objects by assigning particle objects to particles generated from the first particle generation point. Here, 612 and 614 are the first and second particles belonging to the first particle aggregate object.

  Reference numeral 620 denotes a second particle aggregate object for expressing splashes. The particle object is assigned to particles generated from the second particle generation point and is configured as a set of these particle objects. Here, 622 and 624 are the third and fourth particles belonging to the second particle aggregate object.

  Here, in the present embodiment, a reference color for expressing splash is set in the first particle aggregate object and the second particle aggregate object. The reference color may be the same color for the first particle aggregate object and the second particle aggregate object, or may be different colors.

  Then, the depth cueing process is performed based on the reference color and the depth value of the particle generation point of each particle aggregate object, and the color obtained by the depth cueing process is set as the base color of the particle aggregate object, from the same particle generation point. Image generation processing is performed by applying a depth cueing effect to each particle belonging to the generated particle set using the base color.

  In other words, image generation processing is applied to the first particles 612 and the second particles 614 belonging to the first particle aggregate object 610 by applying a depth cueing effect using the base color of the first particle aggregate object 610. I do.

  The third particle 622 and the fourth particle 624 belonging to the second particle aggregate object 610 are applied with a depth queuing effect using the base color of the second particle aggregate object 620 to generate an image. I do.

  Accordingly, the processing can be greatly reduced as compared with the case where the depth queuing processing is performed on each particle constituting the first particle aggregate object and the second particle aggregate object.

  Here, for simplicity of explanation, the description has been made with 612, 614, 622, and 624 as particles, but it may be the vertex of the particle object assigned to the particle.

  30A, 30B, and 30C are diagrams for explaining the depth queuing process performed in this embodiment.

  FIG. 30A is a diagram for explaining the depth cueing process for R (red). The vertical axis represents the value of R (red), and the horizontal axis represents the depth value (Z) of the particle generation point. Reference numeral 630 is the R value of the reference color set for the particle aggregate object, and 640 is the R value of the background color. Reference numeral 635 denotes a function curve for obtaining the R value of the base color based on the depth value.

  For example, when the depth value of the particle generation point is Z1, the base color R value is R1, and when the particle generation point depth value is Z2, the base color R value is R2.

  FIG. 30B is a diagram for explaining the depth cueing process for G (green). The vertical axis represents the value of G (green), and the horizontal axis represents the depth value (Z) at the particle generation point. Reference numeral 650 is an R value of the reference color set for the particle aggregate object, and 660 is a G value of the background color. Reference numeral 655 denotes a function curve for obtaining the G value of the base color based on the depth value.

  For example, when the depth value at the particle generation point is Z1, the base color G value is G1, and when the particle generation point depth value is Z2, the base color G value is G2.

  FIG. 30C is a diagram for explaining the depth cueing process for B (blue). The vertical axis is the value of B (blue), and the horizontal axis is the depth value (Z) of the particle generation point. Reference numeral 670 denotes a B value of the reference color set in the particle aggregate object, and 680 denotes a B value of the background color. Reference numeral 675 denotes a function curve for obtaining the B value of the base color based on the depth value.

  For example, when the depth value at the particle generation point is Z1, the base color B value is B1, and when the particle generation point depth value is Z2, the base color B value is B2.

(6) Prevention of paging by polygon division For example, when image generation is performed using hardware with limited memory resources, the capacity of a real storage area of a VRAM (frame buffer) is limited. For this reason, if a large polygon is drawn in a VRAM (frame buffer), paging occurs and the processing time increases.

  Therefore, in this embodiment, when the depth information of the particle object or the distance from the virtual camera is increased, the occurrence of such paging is prevented by increasing the number of polygons constituting the object assigned to the particle.

  FIG. 31 is a flowchart for explaining an example of polygon division according to this embodiment.

  First, the depth information of the processing target particle is acquired (step S910).

  Next, it is determined whether or not to change the number of divisions based on the depth value, and in the case of changing, a process of dividing polygons and sprites constituting the particle object is performed (steps S920 and S930).

  FIG. 32 shows a state in which sprites (plate polygons) constituting the particle object are divided. 710 is a sprite (plate polygon) before division, and 720 is a sprite (plate polygon) after division.

  Whether the number of divisions should be changed may be determined, for example, depending on whether the depth information has reached a predetermined value, or, for example, particle sorting processing is performed based on the depth information and assigned to particles belonging to the predetermined number from the front. It may be determined depending on whether the polygon or sprite belongs to the object.

3. Hardware Configuration Next, an example of a hardware configuration capable of realizing the present embodiment will be described with reference to FIG.

  The main processor 900 operates based on a program stored in the CD 982 (information storage medium), a program transferred via the communication interface 990, or a program stored in the ROM 950 (one of information storage media). Various processes such as processing, image processing, and sound processing are executed.

  The coprocessor 902 assists the processing of the main processor 900, has a product-sum calculator and a divider capable of high-speed parallel calculation, and executes matrix calculation (vector calculation) at high speed. For example, if a physical simulation for moving or moving an object requires processing such as matrix operation, a program operating on the main processor 900 instructs (requests) the processing to the coprocessor 902. )

  The geometry processor 904 performs geometry processing such as coordinate transformation, perspective transformation, light source calculation, and curved surface generation, has a product-sum calculator and a divider capable of high-speed parallel computation, and performs matrix computation (vector computation). Run fast. For example, when processing such as coordinate transformation, perspective transformation, and light source calculation is performed, a program operating on the main processor 900 instructs the geometry processor 904 to perform the processing.

  The data decompression processor 906 performs a decoding process for decompressing the compressed image data and sound data, and a process for accelerating the decoding process of the main processor 900. As a result, a moving image compressed by a given image compression method can be displayed on an opening screen, an intermission screen, an ending screen, a game screen, or the like. Note that the image data and sound data to be decoded are stored in the ROM 950 and the CD 982 or transferred from the outside via the communication interface 990.

  The drawing processor 910 performs drawing (rendering) processing of an object composed of primitive surfaces such as polygons and curved surfaces at high speed. When drawing an object, the main processor 900 uses the function of the DMA controller 970 to pass the object data to the drawing processor 910 and transfer the texture to the texture storage unit 924 if necessary. Then, the rendering processor 910 renders the object in the frame buffer 922 at high speed while performing hidden surface removal using a Z buffer or the like based on the object data and texture. The drawing processor 910 can also perform α blending (translucent processing), depth cueing, mip mapping, fog processing, trilinear filtering, anti-aliasing, shading processing, and the like. When an image for one frame is written in the frame buffer 922, the image is displayed on the display 912.

  The sound processor 930 includes a multi-channel ADPCM sound source and the like, and generates high-quality game sounds such as BGM, sound effects, and sounds. The generated game sound is output from the speaker 932.

  Operation data from the game controller 942, save data from the memory card 944, and personal data are transferred via the serial interface 940.

  The ROM 950 stores system programs and the like. In the case of an arcade game system, the ROM 950 functions as an information storage medium, and various programs are stored in the ROM 950. A hard disk may be used instead of the ROM 950.

  The RAM 960 is used as a work area for various processors.

  The DMA controller 970 controls DMA transfer between the processor and memory (RAM, VRAM, ROM, etc.).

  The CD drive 980 drives a CD 982 (information storage medium) in which programs, image data, sound data, and the like are stored, and enables access to these programs and data.

  The communication interface 990 is an interface for transferring data to and from the outside via a network. In this case, as a network connected to the communication interface 990, a communication line (analog telephone line, ISDN), a high-speed serial bus, or the like can be considered. By using a communication line, data transfer via the Internet becomes possible. Further, by using the high-speed serial bus, data transfer with other game systems becomes possible.

  All of the means of the present invention may be executed by hardware alone, or may be executed only by a program stored in an information storage medium or a program distributed via a communication interface. Alternatively, it may be executed by both hardware and a program.

  When each means of the present invention is executed by both hardware and a program, a program for executing each means of the present invention using hardware is stored in the information storage medium. Become. More specifically, the program instructs each processor 902, 904, 906, 910, 930, etc., which is hardware, and passes data if necessary. Each processor 902, 904, 906, 910, 930, etc. executes each means of the present invention based on the instruction and the passed data.

  FIG. 34A shows an example when the present embodiment is applied to an arcade game system. The player enjoys the game by operating the lever 1102, the button 1104, and the like while viewing the game image displayed on the display 1100. Various processors and various memories are mounted on the built-in system board (circuit board) 1106. Information (program or data) for executing each means of the present invention is stored in a memory 1108 which is an information storage medium on the system board 1106. Hereinafter, this information is referred to as storage information.

  FIG. 34B shows an example in which the present embodiment is applied to a home game system. The player enjoys the game by operating the game controllers 1202 and 1204 while viewing the game image displayed on the display 1200. In this case, the stored information is stored in the CD 1206, which is an information storage medium that is detachable from the main system, or in the memory cards 1208, 1209, and the like.

  FIG. 34C shows a host device 1300 and terminals 1304-1 to 1304-n connected to the host device 1300 via a network 1302 (a small-scale network such as a LAN or a wide area network such as the Internet). An example of applying this embodiment to a system including In this case, the stored information is stored in an information storage medium 1306 such as a magnetic disk device, a magnetic tape device, or a memory that can be controlled by the host device 1300, for example. When the terminals 1304-1 to 1304-n can generate game images and game sounds stand-alone, the host device 1300 receives a game program and the like for generating game images and game sounds from the terminal 1304-. 1 to 1304-n. On the other hand, if it cannot be generated stand-alone, the host device 1300 generates a game image and a game sound, which is transmitted to the terminals 1304-1 to 1304-n and output at the terminal.

  In the case of the configuration shown in FIG. 34C, each unit of the present invention may be executed in a distributed manner between the host device (server) and the terminal. The storage information for executing each means of the present invention may be distributed and stored in the information storage medium of the host device (server) and the information storage medium of the terminal.

  The terminal connected to the network may be a home game system or an arcade game system. When connecting the arcade game system to a network, a portable information storage device capable of exchanging information with the arcade game system and exchanging information with the home game system. It is desirable to use (memory card, portable game device).

  The present invention is not limited to that described in the above embodiment, and various modifications can be made.

  For example, in the invention according to the dependent claims of the present invention, a part of the constituent features of the dependent claims can be omitted. Moreover, the principal part of the invention according to one independent claim of the present invention can be made dependent on another independent claim.

  In addition, the display object that can be expressed by the method of the present invention is not limited to splashing, and can display various display objects that irradiate light while deforming into an indefinite shape, such as fireworks, explosions, lightning, and shining amoeba. .

  Further, the particle control method is not limited to the method described in the present embodiment.

  Further, in the present embodiment, the case where the object is composed of polygons is mainly described, but the case where the object is composed of other forms of primitive surfaces such as a free-form surface is also included in the scope of the present invention.

  The present invention can also be applied to various games (such as fighting games, shooting games, robot fighting games, sports games, competitive games, role playing games, music playing games, dance games, etc.).

  The present invention is also applicable to various game systems (image generation systems) such as a commercial game system, a home game system, a large attraction system in which a large number of players participate, a simulator, a multimedia terminal, and a system board for generating game images. Applicable.

100 processor 110 game processor 120 image generator 130 drawing order determination processor 132 particle padding processor 134 particle load reduction processor 140 drawing unit 150 sound generator 160 operating unit 170 storage unit 172 main memory 174 frame buffer 180 information storage Medium 190 Display unit 192 Sound output unit 194 Portable information storage device 196 Communication unit

Claims (33)

An image generation system,
A means for changing at least one of the number of particle generation points, the number of particles, and the lifetime of particles based on information on a processing load at the time of image generation;
Means for generating an image that is visible from a given viewpoint in the object space using particles;
An image generation system comprising: In claim 1,
The number of particles is the number of particles existing on one screen or the number of particles generated from a given generation point. In any one of Claims 1 thru | or 2.
An image generation system that reduces processing load by preferentially shortening the lifetime of particles that are away from the virtual camera based on particle depth information. In any one of Claims 1 thru | or 3,
An image generation system which reduces processing load by preferentially excluding a set of particles generated from a particle generation point away from a virtual camera based on depth information of a particle generation point, and excluding the image generation target. In any one of Claims 1 thru | or 4,
An image generation system that reduces processing load by reducing the number of particles that are generated preferentially from a particle generation point remote from a virtual camera based on depth information of the particle generation point. In any one of Claims 1 thru | or 5,
An image generation system that reduces processing load by lowering the precision of an object in preference to an object assigned to a particle far from a virtual camera based on particle depth information. In any one of Claims 1 thru | or 6.
An image generation system that reduces processing load by lowering the precision of an object in preference to an object assigned to a particle generated from a particle generation point remote from the virtual camera based on depth information of the particle generation point. An image generation system,
Means for excluding the particle or the object assigned to the particle from the target of image generation when the transparency given to the particle or the object assigned to the particle is smaller than a predetermined value;
Means for generating an image that is visible from a given viewpoint in the object space using particles;
An image generation system comprising: An image generation system,
Means for performing the annihilation process of the particle or the object assigned to the particle when the height of the particle reaches a predetermined value;
Means for generating an image that is visible from a given viewpoint in the object space using particles;
An image generation system comprising: In claim 9,
The annihilation process includes a case where a particle or an object assigned to the particle annihilates after a predetermined time has elapsed. An image generation system,
Based on the depth information of the particle, it is determined whether there is an object that blocks the field of vision in front of it, and when there is an object that blocks the field of view, the means to exclude the particle or the object assigned to the particle from the target of image generation,
Means for generating an image that is visible from a given viewpoint in the object space using particles;
An image generation system comprising: An image generation system,
Means for performing depth cueing processing based on depth information of the particle generation point with respect to a reference color set for the particle set object represented by the particle set generated from the same particle generation point;
The color obtained by the depth cueing process is used as the base color of the particle set object, and the depth cueing effect is applied to each particle belonging to the particle set generated from the same particle generation point using the base color. Means for performing image generation processing;
An image generation system comprising: An image generation system,
Means for controlling the number of divisions of the primitive constituting the particle object based on at least one of the depth information of the particle object, the positional relationship with the virtual camera, and the ratio of the drawing area in the screen of the primitive constituting the particle object;
Means for generating an image that is visible from a given viewpoint in the object space using particles;
An image generation system comprising: In claim 13,
An image generation system characterized by increasing the number of divisions of primitives constituting a particle object when the depth information of the particle object or the distance from the virtual camera increases. In claim 13,
An image generation system characterized by increasing the number of divisions of primitives constituting particles when the ratio of the drawing area to the screen of primitives constituting the particle object increases. In any one of Claims 13 thru | or 15,
An image generation system characterized in that the number of divisions is increased by subdividing primitives assigned to particles. A computer usable program,
A means for changing at least one of the number of particle generation points, the number of particles, and the lifetime of particles based on information on a processing load at the time of image generation;
Means for generating an image that is visible from a given viewpoint in the object space using particles;
A program characterized by causing a computer to realize. In claim 17,
The number of particles is the number of particles existing on one screen or the number of particles generated from a given generation point. In any of claims 17 to 18,
A program characterized by reducing processing load by shortening the lifetime in preference to particles far from the virtual camera based on particle depth information. In any of claims 17 to 19,
A program that reduces processing load by preferentially excluding a set of particles generated from a particle generation point away from a virtual camera based on depth information of a particle generation point, and excluding it from image generation. In any one of claims 17 to 20,
A program that reduces processing load by reducing the number of particles that are generated preferentially from particle generation points far from the virtual camera based on depth information of particle generation points. A device according to any one of claims 17 to 21.
A program characterized by reducing processing load by lowering the precision of an object in preference to an object assigned to a particle away from a virtual camera based on particle depth information. In any of claims 17 to 22,
A program that reduces processing load by lowering the precision of an object in preference to an object assigned to a particle generated from a particle generation point remote from the virtual camera based on depth information of the particle generation point. A computer usable program,
Means for excluding the particle or the object assigned to the particle from the target of image generation when the transparency given to the particle or the object assigned to the particle is smaller than a predetermined value;
Means for generating an image that is visible from a given viewpoint in the object space using particles;
A program characterized by causing a computer to realize. A computer usable program,
Means for performing the annihilation process of the particle or the object assigned to the particle when the height of the particle reaches a predetermined value;
Means for generating an image that is visible from a given viewpoint in the object space using particles;
A program characterized by causing a computer to realize. In claim 25,
The annihilation process includes a case where a particle or an object assigned to the particle annihilates after a predetermined time has elapsed. A computer usable program,
Based on the depth information of the particle, it is determined whether there is an object that blocks the field of vision in front of it, and when there is an object that blocks the field of view, the means to exclude the particle or the object assigned to the particle from the target of image generation,
Means for generating an image that is visible from a given viewpoint in the object space using particles;
A program characterized by causing a computer to realize. A computer usable program,
Means for performing depth cueing processing based on depth information of the particle generation point with respect to a reference color set for the particle set object represented by the particle set generated from the same particle generation point;
The color obtained by the depth cueing process is used as the base color of the particle set object, and the depth cueing effect is applied to each particle belonging to the particle set generated from the same particle generation point using the base color. Means for performing image generation processing;
A program characterized by causing a computer to realize. A computer usable program,
Means for controlling the number of divisions of the primitive constituting the particle object based on at least one of the depth information of the particle object, the positional relationship with the virtual camera, and the ratio of the drawing area in the screen of the primitive constituting the particle object;
Means for generating an image that is visible from a given viewpoint in the object space using particles;
A program characterized by causing a computer to realize. In claim 29,
A program for increasing the number of divisions of primitives constituting a particle object when the depth information of the particle object or the distance from the virtual camera increases. In claim 29,
A program characterized by increasing the number of divisions of primitives constituting particles when the ratio of the drawing area to the screen of primitives constituting the particle object increases. Any one of claims 29 to 31
A program characterized by increasing the number of divisions by subdividing primitives assigned to particles.   An information storage medium usable by a computer, comprising the program according to any one of claims 17 to 32.