JP4680670B2 - Program, information storage medium, and image generation system - Google Patents

Description

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

  Conventionally, an image generation system (game system) that generates an image that can be seen from a virtual camera (a given viewpoint) in an object space that is a virtual three-dimensional space is known. Popular. Taking an image generation system capable of enjoying a role-playing game (RPG) as an example, a player operates a player character (player object), which is his or her own character, to move it on a map in the object space, and to create an enemy character. Enjoy the game by playing against (enemy objects), interacting with other characters, and visiting various towns.

  In such an image generation system, a post-filter method (post-effect method) is known in which an image drawn once (original image) is further processed to create an image having an atmosphere different from that of the original image. It has been. For example, a technique for blurring an original image using a blur filter, a technique for performing edge enhancement using a color difference filter, and the like are known. In addition, there is a fluctuation filter that distorts the original image with the passage of time to express the heat and fluctuations (ripples) of the water surface.

However, the post-filter method is a two-dimensional image processing method, and many of them apply image effects regardless of the change of the object in the object space of the object represented in the original image or the change of the virtual camera. It is to be added. For this reason, when performing a filtering process that distorts the original image over time, the distortion pattern interferes with the movement of the virtual camera, resulting in a poor-looking image after filtering. There was a problem.
Japanese Patent No. 3401204

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a program, an information storage medium, and a program that can create a high-quality video image that has been subjected to filter processing.

  (1) The present invention is an image generation system for generating an image, and a virtual camera control unit that controls a virtual camera based on given control information, and an image viewed from the virtual camera in an object space When it is determined that at least one of the position, direction, and angle of view of the virtual camera has changed based on the rendering unit that performs filtering on the rendered original image and the control information of the virtual camera, And a parameter setting unit that changes a filter strength parameter of the filter processing. The present invention also relates to a program that causes a computer to function as each of the above-described units. The present invention also relates to an information storage medium that can be read by a computer and stores (records) a program that causes the computer to function as each of the above-described units.

  The computer refers to a physical device (system) having basic components such as a processor (processing unit: CPU or GPU), a memory (storage unit), an input device, and an output device. The same applies to the following.

  According to the present invention, the filter strength parameter is changed when it is determined that at least one of the position, direction, and angle of view of the virtual camera has changed, so that the degree of influence of the filtering process on the original image is appropriately adjusted. can do. For this reason, according to the present invention, it is possible to prevent the image after filtering from being unnatural and poor in appearance, and a high-quality video can be created.

  (2) In the image generation system, the program, and the information storage medium of the present invention, the filter process is a pixel replacement process, and the parameter setting unit includes at least one of the position, direction, and angle of view of the virtual camera. The filter strength parameter may be changed so that the pixel replacement distance in the pixel replacement process is reduced when it is determined that one has changed. In this way, when at least one of the position, direction, and angle of view of the virtual camera changes, the pixel arrangement is gradually replaced, so that it is possible to prevent the appearance of the image from being deteriorated.

  (3) In the image generation system, the program, and the information storage medium of the present invention, the filtering process is a pixel replacement process in which a pixel replacement distance is determined based on a periodic function, and the parameter setting unit includes the parameter setting unit, When it is determined that at least one of the position, direction, and angle of view of the virtual camera has changed, the filter strength parameter may be changed so that the amplitude component of the periodic function becomes small. In this way, the fluctuation amount of the pixel replacement distance within one cycle in the pixel replacement process is reduced. That is, since the state of changing the pixel array changes gradually, it is possible to prevent the appearance of the image from deteriorating.

  (4) In the image generation system, the program, and the information storage medium of the present invention, the filter process is a pixel replacement process in which a pixel replacement distance is determined based on a periodic function, and the parameter setting unit includes the parameter setting unit, When it is determined that at least one of the position, direction, and angle of view of the virtual camera has changed, the filter strength parameter may be changed so that the frequency component of the periodic function is increased. In this way, the pixel replacement period in the pixel replacement process becomes longer. That is, since the replacement of the pixel array per unit time becomes gradual, it is possible to prevent the appearance of the image from being deteriorated.

  (5) In the image generation system, the program, and the information storage medium of the present invention, the control information includes movement distance information of the gazing point of the virtual camera, and the parameter setting unit moves the gazing point of the virtual camera. The filter strength parameter may be changed when it is determined that at least one of the position, the direction, and the angle of view of the virtual camera has changed based on the distance information. In this way, when at least one of the position, direction, and angle of view of the virtual camera changes with the movement of the gazing point of the virtual camera, the degree of influence of the filtering process on the original image is made appropriate. The filter strength parameter can be changed.

  (6) In the image generation system, the program, and the information storage medium of the present invention, the parameter setting unit sets the filter strength parameter when the moving distance of the gazing point of the virtual camera is larger than a given threshold value. You may make it perform the process which approaches from a 1st level to the 2nd level lower than this 1st level. By providing the threshold moving amount in this way, it is possible to prevent the filter strength parameter from fluctuating frequently only by slightly moving the gazing point of the virtual camera.

(7) In the image generation system, the program, and the information storage medium of the present invention, the parameter setting unit is configured so that the moving distance of the gazing point of the virtual camera falls below the threshold after the threshold is exceeded. When it has changed, the filter strength parameter may be returned from the second level to the first level. In this way, when the movement of the gazing point of the virtual camera decreases, the effect of the filtering process is reflected in the original image, and it is possible to prevent the image from appearing unnatural (8). In the image generation system, program, and information storage medium of the present invention, a gazing point of the virtual camera is set for a moving object, and the parameter setting unit moves the moving object in the object space. When the gazing point of the virtual camera moves, the filter strength parameter may be changed according to the moving distance. In this way, the filter strength parameter may be changed only when the mobile object to be noticed moves in the object space, so that the processing becomes simple.

  (9) In the image generation system, the program, and the information storage medium of the present invention, the drawing unit sets the α value set in the α plane of the original image in which the filtering target object is drawn with an α value different from other objects. May be used as mask information to perform the filtering process on the original image. In this way, the processing content can be simplified when locally filtering the original image.

  Hereinafter, this embodiment will be described. In addition, this embodiment demonstrated below does not unduly limit the content of this invention described in the claim. In addition, all the configurations described in the present embodiment are not necessarily essential configuration requirements of the present invention.

1. Configuration FIG. 1 shows an example of a functional block diagram of an image generation system (game system) of the present embodiment. Note that the image generation system of the present embodiment may have a configuration in which some of the components (each unit) in FIG. 1 are omitted.

  The operation unit 160 is for a player to input operation data of a player object (an example of a moving object, a player character operated by the player), and functions thereof are a lever, a button, a steering, a microphone, and a touch panel display. Alternatively, it can be realized by a housing or the like. The storage unit 170 serves as a work area for the processing unit 100, the communication unit 196, and the like, and its function can be realized by a RAM (VRAM) or the like.

  The information storage medium 180 (computer-readable medium) stores programs, data, and the like, and functions as an optical disk (CD, DVD), magneto-optical disk (MO), magnetic disk, hard disk, and magnetic tape. Alternatively, it can be realized by a memory (ROM). The processing unit 100 performs various processes of the present embodiment based on a program (data) stored in the information storage medium 180. That is, the information storage medium 180 stores a program for causing a computer to function as each unit of the present embodiment (a program for causing a computer to execute processing of each unit).

  The display unit 190 outputs an image generated according to the present embodiment, and its function can be realized by a CRT, LCD, touch panel display, HMD (head mounted display), or the like. The sound output unit 192 outputs the sound generated by the present embodiment, and its function can be realized by a speaker, headphones, or the like.

  The portable information storage device 194 stores player personal data, game save data, and the like. Examples of the portable information storage device 194 include a memory card and a portable game device. The communication unit 196 performs various controls for communicating with the outside (for example, a host device or other image generation system), and functions thereof are hardware such as various processors or communication ASICs, programs, and the like. It can be realized by.

  Note that a program (data) for causing a computer to function as each unit of this embodiment is distributed from the information storage medium of the host device (server) to the information storage medium 180 (storage unit 170) via the network and communication unit 196. May be. Use of the information storage medium of such a host device (server) can also be included in the scope of the present invention.

  The processing unit 100 (processor) performs processing such as game processing, image generation processing, or sound generation processing based on operation data and programs from the operation unit 160. Here, as the game process, a process for starting a game when a game start condition is satisfied, a process for advancing the game, a process for placing an object such as a character or a map, a process for displaying an object, and a game result are calculated. There is a process or a process of ending a game when a game end condition is satisfied. The processing unit 100 performs various processes using the main storage unit 171 in the storage unit 170 as a work area. The functions of the processing unit 100 can be realized by hardware such as various processors (CPU, DSP, etc.), ASIC (gate array, etc.), and programs.

  The processing unit 100 includes an object space setting unit 110, a movement / motion processing unit 112, a virtual camera control unit 114, a parameter setting unit 116, a drawing unit 120, and a sound generation unit 130. Note that some of these may be omitted.

  The object space setting unit 110 is an object composed of various objects (polygons, free-form surfaces, subdivision surfaces, etc.) representing display objects such as characters, buildings, stadiums, cars, trees, pillars, walls, and maps (terrain). ) Is set in the object space. In other words, the position and rotation angle of the object in the world coordinate system (synonymous with direction and direction) are determined, and the rotation angle (rotation angle around the X, Y, and Z axes) is determined at that position (X, Y, Z). Arrange objects.

  The movement / motion processing unit 112 performs a movement / motion calculation (movement / motion simulation) of an object (such as a character, a car, or an airplane). That is, based on operation data input by the player through the operation unit 160, a program (movement / motion algorithm), various data (motion data), or the like, the object is moved in the object space, or the object is moved (motion, animation). ) Is performed. Specifically, object movement information (position, rotation angle, speed, or acceleration) and motion information (position or rotation angle of each part that constitutes the object) are sequentially transmitted every frame (1/60 seconds). Perform the required simulation process. A frame is a unit of time for performing object movement / motion processing (simulation processing) and image generation processing.

  The virtual camera control unit 114 performs a virtual camera (viewpoint) control process for generating an image viewed from a given (arbitrary) viewpoint in the object space. Specifically, processing for controlling the position (X, Y, Z) or rotation angle (rotation angle about the X, Y, Z axis) of the virtual camera (processing for controlling the viewpoint position, the line-of-sight direction or the angle of view) I do.

  For example, when an object (eg, character, ball, car) is photographed from behind using a virtual camera, the position or rotation angle of the virtual camera (the direction of the virtual camera is set so that the virtual camera follows changes in the position or rotation of the object. ) To control. In this case, the virtual camera can be controlled based on information such as the position, rotation angle, or speed of the object obtained by the movement / motion processing unit 112. Alternatively, the virtual camera may be controlled to rotate at a predetermined rotation angle or to move along a predetermined movement path. In this case, the virtual camera is controlled based on the virtual camera data for specifying the position (movement path) or rotation angle of the virtual camera. When there are a plurality of virtual cameras (viewpoints), the above control process is performed for each virtual camera.

  The virtual camera control unit 114 controls the position (viewpoint position), the direction (gaze direction), the angle of view, and the like based on given control information. Various information such as virtual camera position, direction, angle of view change information, gazing point movement information (movement distance, movement direction), object movement information and rotation information, or operation information of the operation unit 160 are stored. Control information can be arbitrarily determined. For example, when the movement information of the gazing point is used as the control information of the virtual camera, when the position of the gazing point is changed in the object space, the movement distance and movement direction, in other words, the world coordinates (X, The viewpoint position (position), line-of-sight direction (direction), angle of view, etc. of the virtual camera can be controlled in accordance with changes in Y, Z). Note that the movement information of the gazing point in a broad sense includes not only the change information of the position coordinates of the gazing point in the world coordinate system, but also the position coordinates of the gazing point in the camera coordinate system (view point coordinate system) and the screen coordinate system. Also includes change information. In addition, the gazing point of the virtual camera can be set in association with the object. For example, in a system in which a moving object can be moved or operated in the object space based on operation information of the operation unit 160. An arbitrary representative point (for example, center coordinates) of the moving object can be set as the gazing point. In this case, the point of interest moves following the movement or movement of the moving object, and as a result, the position, direction, angle of view, etc. of the virtual camera are controlled so as to follow the movement of the moving object. Will be.

  The parameter setting unit 116 performs a process of setting a filter strength parameter that determines the degree of influence of the filter process. In particular, based on the control information of the virtual camera, at least one of the position, direction, and angle of view of the virtual camera has changed. If it is determined, a process for changing the filter strength parameter of the filter process is performed. For example, the filter strength parameter can be changed when it is determined that at least one of the position, direction, and angle of view of the virtual camera has changed based on the moving distance information of the gazing point of the virtual camera. When a gazing point is set for a moving object, when the moving object moves in the object space and the gazing point of the virtual camera moves, a filter strength parameter is set according to the moving distance. May be changed.

  Here, when performing a filter process including a pixel replacement process as an example of the filter process, the filter strength parameter can be changed so that the pixel replacement distance in the pixel replacement process is reduced. For example, when the pixel replacement process is a process in which the pixel replacement distance is determined based on the periodic function, the parameter changing process for decreasing the amplitude component parameter of the periodic function or increasing the frequency component parameter may be performed. it can. The pixel replacement process is a process of replacing the color information of the Kth pixel with the color information of the Lth pixel according to a given rule, and the pixel replacement distance is the difference between the Kth pixel and the Lth pixel. It is the displacement (distance) between them. In the pixel replacement process, there may be pixels in which pixel replacement does not occur, and the color information of a certain pixel may be replaced as the color information of a plurality of pixels.

  Further, the filter strength parameter changing process can control whether or not the filter strength parameter is permitted based on the relationship between the moving distance of the gazing point of the virtual camera and a preset threshold value. In this way, it can be prevented that the filter strength parameter is frequently changed to deteriorate the appearance of the image. Specifically, when the moving distance of the gazing point of the virtual camera is greater than a given threshold, the process of continuously bringing the filter strength parameter from the first level to the second level lower than the first level It can be performed. In this case, it is preferable to change the filter strength parameter so as to gradually approach the second level from the first level. In addition, when the moving distance of the gazing point of the virtual camera once exceeds the threshold value and then changes to fall below the threshold value, processing for returning the filter strength parameter from the second level to the first level is performed. Can do. Also in this case, it is preferable to continuously change the filter strength parameter from the second level toward the first level.

  The drawing unit 120 performs drawing processing based on the results of various processing (game processing) performed by the processing unit 100, thereby generating an image and outputting the image to the display unit 190. In the case of generating a so-called three-dimensional game image, first, geometric processing such as coordinate transformation (world coordinate transformation, camera coordinate transformation), clipping processing, or perspective transformation is performed, and drawing data ( Primitive vertex position coordinates, texture coordinates, color data, normal vector, α value, etc.) are created. Based on the drawing data (object data), the model object (one or a plurality of primitives) after perspective transformation (after the geometry processing) is converted into a pixel unit such as a drawing buffer 174 (frame buffer or intermediate buffer (work buffer)). The image information is stored in a buffer (VRAM). Thereby, an image that can be seen from the virtual camera (given viewpoint) in the object space is generated. In addition, when there are a plurality of virtual cameras (viewpoints), the drawing process can be performed so that an image seen from each virtual camera can be displayed as a divided image on one screen.

  The drawing unit 120 performs geometry processing, texture mapping, hidden surface removal processing, α blending, and the like as drawing processing.

  In the geometry processing, processing such as coordinate transformation, clipping processing, perspective transformation, or light source calculation is performed on the object. Then, object data (positional coordinates of object vertices, texture coordinates, color data, normal vector, α value, etc.) after geometry processing (after perspective transformation) is stored in the main storage unit 172.

  Texture mapping is a process for mapping a texture (texel value) stored in the texture storage unit 176 to an object. Specifically, the texture (surface properties such as color and α value) is read from the texture storage unit 176 using texture coordinates or the like set (given) to the vertex of the object. Then, a texture that is a two-dimensional image is mapped to an object. In this case, bilinear interpolation or the like is performed as processing for associating pixels with texels or texel interpolation.

  In the present embodiment, text mapping using a color look-up table (CLUT) for index color / texture mapping stored in the LUT storage unit 175 can also be performed as texture mapping. In this case, an index texture in which a number (color) determined based on the relative position of each pixel of the original image or the relative position of each pixel of the divided block obtained by dividing the original image is set as an index number (index color) is used. While referring to a color lookup table that associates index numbers with image information (R component, G component, B component, A component (α component)), virtual objects (display screen size polygons, divided block size polygons) ) Texture mapping. When performing pixel replacement processing, prepare an index texture to replace the index number assigned to each texel of the index texture corresponding to the original image or the divided block of the original image, and use the color lookup table for the index texture. A pixel replacement image (filter image) can be generated by texture mapping to a virtual object while referring to the image.

  As the hidden surface removal processing, hidden surface removal processing may be performed by a Z buffer method (depth comparison method, Z test) using a Z buffer 178 (depth buffer) in which a Z value (depth information) of a drawing pixel is stored. it can. That is, when the drawing pixel corresponding to the primitive of the object is drawn, the Z value stored in the Z buffer 174 is referred to. Then, the Z value of the referenced Z buffer 174 is compared with the Z value at the drawing pixel of the primitive, and the Z value at the drawing pixel is the front side when viewed from the virtual camera (for example, a small Z value). If it is, the drawing process of the drawing pixel is performed and the Z value of the Z buffer 174 is updated to a new Z value.

  As the α blending, a translucent synthesis process (usually α blending, addition α blending, subtraction α blending, or the like) based on the α value (A value) is performed. For example, in the case of normal α blending, the following processes (1) to (3) are performed.

R _Q = (1−α) × R ₁ + α × R ₂ (1)
G _Q = (1−α) × G ₁ + α × G ₂ (2)
B _Q = (1−α) × B ₁ + α × B ₂ (3)
In addition, in the case of addition α blending, the following expressions (4) to (6) are performed. In the case of simple addition, α = 1 and the following formulas (4) to (6) are performed.

R _Q = R ₁ + α × R ₂ (4)
G _Q = G ₁ + α × G ₂ (5)
B _Q = B ₁ + α × B ₂ (6)
In the case of subtractive α blending, the processing of the following equations (7) to (9) is performed. In the case of simple subtraction, α = 1 and the following formulas (7) to (9) are processed.

R _Q = R ₁ −α × R ₂ (7)
G _Q = G ₁ −α × G ₂ (8)
B _Q = B ₁ −α × B ₂ (9)
Here, R ₁ , G ₁ , B ₁ are RGB components of an image (original image) already drawn in the drawing buffer 172, and R ₂ , G ₂ , B ₂ should be drawn in the drawing buffer 172. This is the RGB component of the image. R _Q , G _Q , and B _Q are RGB components of an image obtained by α blending. The α value is information that can be stored in association with each pixel (texel, dot), for example, plus alpha information other than color information. The α value can be used as mask information, translucency (equivalent to transparency and opacity), bump information, and the like.

  In the present embodiment, the drawing unit 120 performs filter processing on the original image in which the image viewed from the virtual camera in the object space is drawn. Although it does not specifically limit as a filter process, The post filter process (post effect process) performed in the unit of a screen or the division | segmentation block unit which divided | segmented the screen into plurality can be performed.

  For example, as the post-filter process, a pixel replacement process in which a pixel replacement distance is determined based on a periodic function can be performed. That is, in the pixel replacement process employed in the present embodiment, the pixel arrangement state of the original image is periodically changed according to the time parameter. At this time, α blending is performed in which the color information of the pixel of the original image and the color information of the replacement pixel are blended based on the α value given according to the Z value of each pixel stored in the Z buffer 174 in the filter processing. Thus, the degree of influence of the color information of the replacement pixel on the color information of the pixel of the original image may be varied according to the depth with respect to the virtual camera. In this way, it is possible to express fluctuations due to the heat.

  The drawing unit 120 generates an original image by drawing the filtering target object with an α value different from that of other objects. Then, filter processing is performed on the original image using the α value set in the α plane of the original image as mask information. Specifically, a filter image corresponding to the original image is generated, and only the drawing area of the filter processing target object drawn with a given α value in the filter image is obtained using the α test technique. Draw a semi-transparent image. Thereby, it is possible to generate an image in which the original image is partially filtered.

  The sound generation unit 130 performs sound processing based on the results of various processes performed by the processing unit 100, generates game sounds such as BGM, sound effects, or sounds, and outputs the game sounds to the sound output unit 192.

  Note that the image generation system of the present embodiment may be a system dedicated to the single player mode in which only one player can play, or may be a system having a multiplayer mode in which a plurality of players can play. 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 by distributed processing using a plurality of terminals (game machine, mobile phone).

2. Next, the method of this embodiment will be described with reference to the drawings. In the following description, the case where the method of the present embodiment is employed with respect to the fluctuation filter processing used when expressing ripples, heat, etc. will be mainly described, but the method of the present embodiment can be applied only to such fluctuation filter processing. It can be applied to various filter processes.

2.1 Fluctuation Filter Method by Pixel Replacement Processing In the present embodiment, fluctuation filter processing is realized by performing pixel replacement processing in which the pixel replacement distance fluctuates periodically using an index color / texture mapping method. Yes.

  Specifically, as shown by A1 in FIG. 2, a filter image (filter filter) generated by dividing the original image drawn in the drawing buffer into a plurality of divided blocks and performing pixel replacement processing in units of the divided blocks. A filtering process is performed to synthesize (semi-transparent drawing) the image of the processed object) with the original image.

  At this time, each divided block has a size of, for example, 16 × 16 pixels, and can be handled as a color lookup table in which these 256 pixels are indexed based on their relative positions, as shown by A2 in FIG. . In addition to the color lookup table (CLUT), as shown at A3 in FIG. 2, a shift table in which the position of each pixel in the divided block is shifted can be prepared, and the shift table can be handled as an index texture. In the shift table, the index number determined based on the relative position of the pixel of the divided block is handled as the coordinate value of the pixel in the divided block, and the index number of the pixel shifted by the pixel replacement distance ΔY is set for each pixel.

  Then, as indicated by A4 in FIG. 2, an index texture set based on the shift table is texture-mapped with respect to the polygon (virtual object) having the divided block size while referring to the color lookup table. Then, as shown at A5 in FIG. 2, a polygon having a divided block size obtained by texture mapping the index texture is drawn at a corresponding position in the original image. By doing in this way, the process which replaces the pixel of an original image is realizable. These processes can be performed on all the divided blocks to generate a filter image corresponding to the original image. Finally, as shown by A6 in FIG. 2, a filter process for applying a post-effect to the original image can be performed by synthesizing the filter image with the original image.

2.2 Filter Strength Parameter Setting Method In this embodiment, when it is determined that at least one of the viewpoint position, line-of-sight direction, and angle of view of the virtual camera has changed, that is, the virtual camera is moved, rotated, zoomed, or When panning or the like, a method of changing the setting of the filter strength parameter of the filter processing is adopted.

  Here, the filter processing of the present embodiment includes pixel replacement processing, and the pixel replacement distance ΔY in the pixel replacement processing is set based on a periodic function as shown in FIG. That is, the shift table set in the index texture is rewritten according to the periodically changing pixel replacement distance ΔY. A plurality of index textures in which the pixel replacement distance ΔY is periodically changed may be prepared in advance. The periodic function is represented by the following formula (A).

ΔY = Asin (ωt + f (x, y)) (A)
As shown in FIG. 3, A is an amplitude component parameter. ω is a frequency component parameter. f (x, y) is an initial phase parameter determined based on the position of the pixel in the divided block. Among these parameters, parameters that are largely related to the strength of the filter processing are the amplitude component parameter A and the frequency component parameter ω. When the amplitude component parameter A is large, the pixel replacement distance ΔY increases and the fluctuation increases. Also, if the frequency component parameter ω is small, the pixel replacement period 2π / ω is shortened, so that the fluctuation speed is increased and the fluctuation per unit time is increased.

  In the present embodiment, as shown in FIG. 4, the gazing point VP of the virtual camera VC is set for the moving object OB that moves in the object space, and when the moving object OB moves, the virtual camera VC The point of interest VP also moves in the object space. The visual line direction of the virtual camera VC is controlled so as to face the gazing point VP. For this reason, when the moving object OB moves and the position of the gazing point VP (three-dimensional coordinates in the world coordinate system) is changed, the scene seen from the virtual camera VC is different.

  By the way, since the filtering process for the original image employed in the present embodiment is a two-dimensional pixel processing process, it is irrelevant to changes in the viewpoint position, line-of-sight direction, angle of view, etc. of the virtual camera. For this reason, if the filtering process is such that its effect varies depending on the time parameter, the variation in image information due to the movement of the virtual camera and the variation in image information due to the effect of the filtering process cause interference, and some sort of The inconvenience of seeing something like the alias of can occur.

  Therefore, in the present embodiment, the filter strength parameter that determines the strength of the filtering process, that is, the degree of influence of the filtering process on the original image, is changed according to the moving distance L of the gazing point VP of the virtual camera VC. The effect is controlled so as to weaken.

  For example, when performing fluctuation filter processing involving pixel replacement processing on the original image, by reducing the amplitude component parameter A of the periodic function shown in FIG. 3, the pixel replacement distance ΔY can be kept short and fluctuation can be reduced. can do. Further, since the change in fluctuation per unit time is reduced by increasing the frequency component parameter ω, the effect of the filter processing can be weakened. Needless to say, it is effective to reduce the amplitude component parameter A and increase the frequency component parameter ω.

  Also, changing the filter strength parameter in this way means changing the appearance of the generated image. For this reason, if the filter strength parameter is frequently changed, there is a risk that the image may be difficult to see. For this reason, in this embodiment, as shown in FIG. 5, when it is determined that the moving distance L of the gazing point VP of the virtual camera VC exceeds a given threshold value Lth, the amplitude component parameter A is set to the first value. The setting is changed from the amplitude level A1 to the second amplitude level A2 lower than the first amplitude level A1. If the movement distance L of the gazing point VP once exceeds the threshold value Lth and then changes below the threshold value Lth, the amplitude parameter A is changed from the second amplitude level A2 to the first amplitude level A1. To return. The change from the first amplitude level A1 to the second amplitude level A2 and the change from the second amplitude level A2 to the first amplitude level A1 are continuously brought close to the target level. This prevents a sudden change in the appearance of the image. The time t2 until the amplitude parameter A is returned from the second amplitude level A2 to the first amplitude level A1 is shorter than the time t1 until the amplitude parameter A is changed from the first amplitude level A1 to the second amplitude level A2. ing. This is because when the fluctuation filter process is constantly performed on the original image, it is preferable to quickly return to the original state.

  As described above, according to the filter strength parameter setting method of the present embodiment, it is possible to appropriately adjust the degree of influence of the filter processing on the original image. For this reason, according to this method, it is possible to prevent the image after filtering from being unnatural and poor in appearance, and it is possible to create a high-quality video. In particular, the method of the present embodiment is suitable when the effect of the filter process changes with time.

2.3 Partial Filter Method Using α Value In this embodiment, in order to perform fluctuation filter processing only on a specific region of the original image, partial filter processing is performed on the original image using the α plane of the original image as mask information. The method to do is adopted.

  Specifically, as shown in FIG. 6, the filtering target object OB1 (α = α1) is drawn with an α value different from those of the other objects OB2 (α = α2) and OB3 (α = α3). Is generated. At this time, the filter image is synthesized only in the region of α ≧ α1 by the α test (semi-transparent drawing), thereby generating an image subjected to the filter processing only in the drawing region of the filter processing target object OB1. Can do. That is, with the partial filter method of the present embodiment, mask information can be drawn on the α plane of the original image simply by drawing the filtering target object OB1 that has been subjected to geometry processing.

  As a method for drawing the α value set in the α plane of the original image so as to be mask information, a method of setting the α component of the vertex color of the vertex of the filter processing target object OB1 to α ≧ α1, filter processing A method in which α ≧ α1 is set in the α plane of the texture mapped to the target object OB1, or the α component of the vertex color of the filtering target object OB1 and the α plane of the texture of the filtering target object OB1 are set. For example, there is a method of setting a value α obtained by multiplying the α value so that α ≧ α1. When mask information is set for the α component of the vertex color of the filtering target object OB1, the object data is stored in the object data storage unit 176. When mask information is set for the α plane of the texture, the texture mapped to the filtering target object OB1 is stored in the texture storage unit 173.

  Note that when creating a filter image in which pixel replacement has been performed in the work buffer, it is preferable to copy the entire original image to the work buffer. In contrast to this, a method of performing partial copying in which only the filtering target object OB1 is drawn in the work buffer is conceivable. However, in this case, color information other than the filtering target object OB1 is lost, and that If the pixels are replaced in a state, an unnatural color protrusion appears in the filter image. For this reason, as shown in FIG. 6, by copying the entire original image to the work buffer and performing a pixel replacement process on the copy image (work image) to generate a filter image, the filter image is unnatural. It is possible to avoid the inconvenience that a protruding color of a large color appears.

3. Processing of this embodiment Next, a detailed processing example of this embodiment will be described with reference to the flowchart of FIG.

  First, an original image is generated by drawing a scene viewed from the virtual camera in a frame buffer so that the α value of a region where ripples occur is α1 (for example, 128) or more and the α value of a region where ripples do not occur is less than α1. (Step S10).

  Next, on the basis of change information such as the position, direction, and angle of view of the virtual camera, whether the wave should be strengthened (whether the wavefront motion will increase) or the wave should be weakened (whether the wavefront motion will be small) Determine (step S11). For example, if the moving distance of the gazing point of the virtual camera exceeds a threshold value, it is determined that the wave should be weakened. In addition, for example, when the moving distance of the point of sight of the virtual camera changes from a state where it exceeds the threshold value to fall below the threshold value, it is determined that the wave should be strengthened.

  Next, a filter strength parameter setting process is performed. Specifically, the wave strength level (first level) when the wavefront motion is large and the wave strength level (second level) when the wavefront motion is small and ripples are set in advance. If the current wave intensity level is determined to be different from the target wave intensity level by comparing the current wave intensity level with the target value, Is performed so that the intensity value (amplitude component parameter or frequency component parameter of the periodic function) approaches the target value (first level or second level) (step S12).

  Next, based on the wave intensity level set in step S12, table data (shift table) for shifting the position coordinates of each point of the pixel is created (step S13). This table data is handled as an index texture in the index color / texture mapping.

  Next, a work buffer (reduction buffer) having a size half that of the frame buffer (display screen) is prepared, and the entire screen (original image) is reduced and copied to the work buffer (step S14).

  Next, the screen (work image) reduced and copied to the work buffer is divided into blocks each having a size of 16 × 16 (pixels), and each divided block is divided into 256 colors indexed by relative positions in the block. It is regarded as a lookup table (CLUT) and is set as a color lookup table for index color / texture mapping (step S15).

  Next, the table data for shifting the pixel position coordinates is regarded as an index texture of 256 colors, and the index texture is mapped to the position corresponding to each divided block while referring to the color lookup table set in step S15. A polygon (virtual object) is drawn (step S16). As a result, a filter image is created in the work buffer.

  Next, the work buffer for storing the image (filter image) subjected to the pixel replacement process is enlarged to the size of the frame buffer and written to the frame buffer (step S17). At this time, the α test is used to determine the state of the most significant bit of the α value bit string, and the pixels of the image obtained by enlarging the image stored in the work buffer only to pixels whose α value is α1 (for example, 128) or more are half Combine with the original image of the frame buffer by transparent drawing.

4). Hardware Configuration FIG. 8 shows an example of a hardware configuration capable of realizing this embodiment. The main processor 900 operates based on a program stored in a DVD 982 (information storage medium, which may be a CD), a program downloaded via the communication interface 990, a program stored in the ROM 950, or the like. Perform processing, sound processing, etc. The coprocessor 902 assists the processing of the main processor 900, and executes matrix operation (vector operation) at high speed. For example, when a matrix calculation process is required for a physical simulation for moving or moving an object, a program operating on the main processor 900 instructs (requests) the process to the coprocessor 902.

  The geometry processor 904 performs geometry processing such as coordinate conversion, perspective conversion, light source calculation, and curved surface generation based on an instruction from a program operating on the main processor 900, and executes matrix calculation at high speed. The data decompression processor 906 performs decoding processing of the compressed image data and sound data and accelerates the decoding processing of the main processor 900. Thereby, a moving image compressed by the MPEG method or the like can be displayed on the opening screen or the game screen.

  The drawing processor 910 executes drawing (rendering) processing of an object composed of primitive surfaces such as polygons and curved surfaces. When drawing an object, the main processor 900 uses the DMA controller 970 to pass the drawing data (vertex data and other parameters) to the drawing processor 910 and, if necessary, the texture to the texture storage unit 924. Forward. Then, the drawing processor 910 draws the object in the frame buffer 922 while performing hidden surface removal using a Z buffer or the like based on the drawing data and texture. The drawing processor 910 also performs α blending (translucent processing), depth cueing, mip mapping, fog processing, bilinear filtering, 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, generates game sounds such as BGM, sound effects, and sounds, and outputs them through the speaker 932. Data from the game controller 942 and the memory card 944 is input 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 a work area for various processors. The DMA controller 970 controls DMA transfer between the processor and the memory. The DVD drive 980 (may be a CD drive) accesses a DVD 982 (may be a CD) in which programs, image data, sound data, and the like are stored. The communication interface 990 performs data transfer with the outside via a network (communication line, high-speed serial bus).

  The processing of each unit (each unit) in this embodiment may be realized entirely by hardware, or may be realized by a program stored in an information storage medium or a program distributed via a communication interface. Also good. Alternatively, it may be realized by both hardware and a program.

  When the processing of each part of this embodiment is realized by both hardware and a program, a program for causing the hardware (computer) to function as each part of this embodiment is stored in the information storage medium. More specifically, the program instructs the processors 902, 904, 906, 910, and 930, which are hardware, and passes data if necessary. Each processor 902, 904, 906, 910, 930 realizes the processing of each unit of the present invention based on the instruction and the passed data.

  The present invention is not limited to that described in the above embodiment, and various modifications can be made. For example, terms cited as broad or synonymous terms in the description in the specification or drawings can be replaced with broad or synonymous terms in other descriptions in the specification or drawings. Further, the fluctuation filter method, the filter strength parameter setting method, the partial filter method, and the like are not limited to those described in the present embodiment, and techniques equivalent to these are 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.). Further, the present invention is applied to various image generation systems such as a business game system, a home game system, a large attraction system in which a large number of players participate, a simulator, a multimedia terminal, a system board for generating a game image, and a mobile phone. it can.

The functional block diagram of the image generation system of this embodiment. Explanatory drawing of the method of this embodiment. Explanatory drawing of the method of this embodiment. Explanatory drawing of the method of this embodiment. Explanatory drawing of the method of this embodiment. Explanatory drawing of the method of this embodiment. The flowchart which shows the specific process example of this embodiment. Hardware configuration example.

Explanation of symbols

100 processing unit,
110 Object space setting unit, 112 Movement / motion processing unit,
114 virtual camera control unit, 116 parameter setting unit,
120 drawing units, 122 filter processing units, 130 sound generation units,
160 operation unit, 170 storage unit,
171 main storage unit, 172 drawing buffer, 173 texture storage unit,
174 Z buffer, 175 LUT storage unit, 176 Object data storage unit,
180 information storage medium, 190 display unit, 192 sound output unit,
194 Portable information storage device, 196 communication unit

Claims (12)

A program for generating an image,
A virtual camera control unit that controls the virtual camera based on given control information;
For each pixel of the original image in which the image viewed from the virtual camera in the object space is drawn, a distance value from the pixel to the other pixel for replacing the pixel with another pixel is determined based on a periodic function, A drawing unit that performs a filtering process to replace a pixel with the other pixel at the distance value;
As a parameter setting unit that reduces the amplitude component of the periodic function when it is determined that at least one of the position, direction, and angle of view of the virtual camera has changed based on the control information of the virtual camera,
A program characterized by causing a computer to function. In claim 1 ,
The parameter setting unit
A program for increasing the frequency component of the periodic function when it is determined that at least one of the position, direction, and angle of view of the virtual camera has changed. In claim 1 or 2 ,
The control information includes movement distance information of the gazing point of the virtual camera,
The parameter setting unit
A program that changes the amplitude component when it is determined that at least one of the position, direction, and angle of view of the virtual camera has changed based on movement distance information of the gazing point of the virtual camera. . In claim 3 ,
The parameter setting unit
When the moving distance of the gazing point of the virtual camera is greater than a given threshold value, the amplitude component is processed from a first level to a second level lower than the first level. Program to do. In claim 4 ,
The parameter setting unit
A process of returning the amplitude component from the second level to the first level when the moving distance of the gazing point of the virtual camera changes below the threshold after exceeding the threshold; A program characterized by being performed. In any one of Claims 3-5 ,
A gazing point of the virtual camera is set for the moving object,
The parameter setting unit
When the moving object moves in the object space and the gazing point of the virtual camera moves, the amplitude component is changed according to the moving distance. A program for generating an image,
A virtual camera control unit that controls the virtual camera based on given control information;
For each pixel of the original image in which the image viewed from the virtual camera in the object space is drawn, a distance value from the pixel to the other pixel for replacing the pixel with another pixel is determined based on a periodic function, A drawing unit that performs a filtering process to replace a pixel with the other pixel at the distance value;
As a parameter setting unit that increases the frequency component of the periodic function when it is determined that at least one of the position, direction, and angle of view of the virtual camera has changed based on the control information of the virtual camera,
A program characterized by causing a computer to function. A program for generating an image,
A virtual camera control unit that controls the virtual camera based on given control information;
A drawing unit that performs a filtering process on an original image obtained by drawing an image viewed from the virtual camera in the object space;
Based on the control information of the virtual camera, when it is determined that at least one of the position, direction, and angle of view of the virtual camera has changed, as a parameter setting unit that changes the filter strength parameter of the filtering process,
Make the computer work,
The control information includes movement distance information of the gazing point of the virtual camera,
The parameter setting unit
When it is determined that at least one of the position, direction, and angle of view of the virtual camera has changed, the filter strength parameter is changed based on movement distance information of the gazing point of the virtual camera. program. An information storage medium readable by a computer, wherein the program according to any one of claims 1 to 8 is stored. An image generation system for generating an image,
A virtual camera control unit that controls the virtual camera based on given control information;
For each pixel of the original image in which the image viewed from the virtual camera in the object space is drawn, a distance value from the pixel to the other pixel for replacing the pixel with another pixel is determined based on a periodic function, A drawing unit that performs a filtering process to replace a pixel with the other pixel at the distance value;
A parameter setting unit that reduces the amplitude component of the periodic function when it is determined that at least one of the position, direction, and angle of view of the virtual camera has changed based on the control information of the virtual camera;
An image generation system comprising: An image generation system for generating an image,
A virtual camera control unit that controls the virtual camera based on given control information;
For each pixel of the original image in which the image viewed from the virtual camera in the object space is drawn, a distance value from the pixel to the other pixel for replacing the pixel with another pixel is determined based on a periodic function, A drawing unit that performs a filtering process to replace a pixel with the other pixel at the distance value;
A parameter setting unit that increases the frequency component of the periodic function when it is determined that at least one of the position, direction, and angle of view of the virtual camera has changed based on the control information of the virtual camera;
An image generation system comprising: An image generation system for generating an image,
A virtual camera control unit that controls the virtual camera based on given control information;
A drawing unit that performs a filtering process on an original image obtained by drawing an image viewed from the virtual camera in the object space;
A parameter setting unit that changes a filter strength parameter of the filter process when it is determined that at least one of the position, direction, and angle of view of the virtual camera has changed based on the control information of the virtual camera. ,
The control information includes movement distance information of the gazing point of the virtual camera,
The parameter setting unit
When it is determined that at least one of the position, direction, and angle of view of the virtual camera has changed, the filter strength parameter is changed based on movement distance information of the gazing point of the virtual camera. Image generation system.

Images