JP2008310377A - Image generation system, program and information storage medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image generation system, a program and an information storage medium for performing the appropriate plotting of a semi-transparent object corresponding to various circumstances. <P>SOLUTION: This image generation system is composed to decide whether or not the value of the transparency information of a pixel corresponding to an object is within a predetermined reference range, and to, when deciding that the value of the transparency information is within the reference range, plot the color information of the pixel based on the transparency information without plotting the depth information of the pixel, and to, when deciding that the value of the transparency information is not within the reference range, plot the depth information of the pixel, and to plot the color information of the pixel based on the transparency information. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  Conventionally, there is known an image generation system that generates an image that can be viewed from a virtual camera (a given viewpoint) in an object space (virtual three-dimensional space) in which an object is set, and can experience so-called virtual reality. Popular as a thing.

In such an image generation system, when an object is drawn by a Z buffer method that refers to depth information, an α value (transparency information) is a predetermined value as a technique for correctly drawing an object including a translucent portion. There is known a method of determining whether or not the condition is satisfied and switching the drawing mode (see, for example, Patent Document 1).
JP-A-11-102179

  However, the above-described image generation system has a problem in that since the above conditions are pre-installed in hardware, the degree of freedom of conditions that can be set is small, and it is not possible to switch between drawing modes corresponding to various situations.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an image generation system, a program, and a program capable of drawing an appropriate translucent object corresponding to various situations, and An object is to provide an information storage medium.

(1) The present invention is a program for generating an image visible from a virtual camera in an object space,
An object space setting section for setting an object in the object space;
A determination unit that determines whether or not a value of transparency information of a pixel corresponding to the object is in a given reference range;
When it is determined that the value of the transparency information is within the reference range, the pixel color information is drawn based on the transparency information without drawing the depth information of the pixel,
When it is determined that the value of the transparency information is not within the reference range, a drawing unit that draws the depth information of the pixel and draws the color information of the pixel based on the transparency information;
And making the computer function.

  The present invention also relates to an image generation system including the above-described units. The present invention is also a computer-readable information storage medium, and relates to an information storage medium storing a program that causes a computer to function as each of the above-described units.

  According to the present invention, it is determined whether or not the value of transparency information of a pixel is within a given reference range, the mode for drawing depth information and color information, and the color information is drawn without drawing the depth information. By performing the process of switching between modes, it is possible to draw an appropriate translucent object.

(2) In the program and information storage medium according to the present invention,
The reference range is a range including a value with the highest transparency and a range not including a value with the lowest transparency.

  According to the present invention, an appropriate drawing process can be performed even when an object located behind the object after drawing the semi-transparent object is further drawn.

(3) In the program and information storage medium according to the present invention,
A storage unit for storing the reference range corresponding to the object;
Make your computer work,
The determination unit
It is determined whether or not the value of the transparency information is within the reference range stored in the storage unit.

  In the present invention, the reference information corresponding to an object includes reference information stored in association with each object when there are a plurality of objects.

  In the present invention, determining whether the value of transparency information is within the reference range stored in the storage unit means that the value of the transparency information corresponding to the object is stored in association with the object. It includes the case where it is determined whether or not.

  According to the present invention, it is possible to set an optimum reference range for each object, and it is possible to draw an appropriate translucent object.

(4) In the program and information storage medium according to the present invention,
A changing unit for changing the reference range stored in the storage unit;
And making the computer function.

  According to the present invention, it is possible to set an appropriate reference range according to the situation at the time of drawing, and to draw an appropriate translucent object.

(5) In the program and information storage medium according to the present invention,
The changing unit is
The reference range stored in the storage unit is changed based on the position of the virtual camera in the object space.

  According to the present invention, it is possible to set an appropriate reference range according to the position of the virtual camera, and to draw an appropriate translucent object.

(6) In the program and information storage medium according to the present invention,
The changing unit is
The reference range stored in the storage unit is changed based on the position of the object in the object space.

  According to the present invention, it is possible to set an appropriate reference range according to the position of the object, and to draw an appropriate translucent object.

  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 vehicle 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 the present 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 172 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 reference range changing 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. In particular, in the present embodiment, the object data storage unit 176 of the storage unit 170 stores object data of objects (moving object, background object) in the object space, and processing for arranging these objects in the object space I do.

  Particularly in the present embodiment, the object data storage unit 176 stores a reference range corresponding to each object. Further, the reference range may be stored without being associated with the object. The object data storage unit 176 may store a reference range corresponding to each virtual camera. In the present embodiment, if the highest transparency value is 0 and the lowest transparency value is 1 as the reference range, an arbitrary range from 0 to 1 (for example, a range from 0 to 0.2) is set and stored. Is done.

  The movement / motion processing unit 112 performs a movement / motion calculation (movement / motion simulation) of an object (character, car, train, airplane, etc.). 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). ) Process. 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 calculated object movement information and motion information are stored in the object data storage unit 176.

  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, a process for controlling and calculating the position (X, Y, Z) or rotation angle (rotation angle around the X, Y, Z axes) of the virtual camera (controls the viewpoint position, the line-of-sight direction or the angle of view) Process). The calculated movement information (position, rotation angle) of the virtual camera is stored in the object data storage unit 176.

  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 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. When generating a so-called three-dimensional game image, first, object data (model data) including vertex data (vertex position coordinates, texture coordinates, color data, normal vector, α value, etc.) of each vertex of the object (model) ) Is input, and vertex processing (shading by a vertex shader) is performed based on the vertex data included in the input object data. When performing the vertex processing, vertex generation processing (tessellation, curved surface division, polygon division) for re-dividing the polygon may be performed as necessary. In the vertex processing, according to the vertex processing program (vertex shader program, first shader program), vertex movement processing, coordinate conversion (world coordinate conversion, camera coordinate conversion), clipping processing, perspective processing, and other geometric processing are performed. On the basis of the processing result, the vertex data given to the vertex group constituting the object is changed (updated or adjusted). Then, rasterization (scan conversion) is performed based on the vertex data after the vertex processing, and the surface of the polygon (primitive) is associated with the pixel. Subsequent to rasterization, pixel processing (shading or fragment processing by a pixel shader) for drawing pixels (fragments forming a display screen) constituting an image is performed. In pixel processing, according to a pixel processing program (pixel shader program, second shader program), various processes such as texture reading (texture mapping), color data setting / change, translucent composition, anti-aliasing, etc. are performed, and an image is processed. Determines the final drawing color of the constituent pixels and outputs the drawing color (color information) of the perspective-transformed object to the drawing buffer 174 (buffer that can store image information in units of pixels; frame buffer, VRAM, rendering target) (draw. That is, in pixel processing, per-pixel processing for setting or changing image information (color, normal, luminance, α value, etc.) in units of pixels is performed. Thereby, an image that can be seen from the virtual camera (given viewpoint) in the object space is generated. Note that when there are a plurality of virtual cameras (viewpoints), an image can be generated so that an image seen from each virtual camera can be displayed as a divided image on one screen.

  The vertex processing and pixel processing are realized by hardware that enables polygon (primitive) drawing processing to be programmed by a shader program written in a shading language, so-called programmable shaders (vertex shaders and pixel shaders). Programmable shaders can be programmed with vertex-level processing and pixel-level processing, so that the degree of freedom of drawing processing is high, and expressive power is greatly improved compared to conventional hardware-based fixed drawing processing. Can do.

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

  In the geometry processing, processing such as coordinate conversion, clipping processing, perspective projection conversion, or light source calculation is performed on the object. Then, object data (positional coordinates of object vertices, texture coordinates, color data (luminance data), normal vector, α value, etc.) after geometry processing (after perspective projection conversion) is stored in the object data storage unit 176. Is done.

  Texture mapping is a process for mapping a texture (texel value) stored in the texture storage unit 178 of the storage unit 170 to an object. Specifically, the texture (surface properties such as color (RGB) and α value) is read from the texture storage unit 178 of the storage unit 170 using the texture coordinates set (given) at the vertex of the object. Then, a texture that is a two-dimensional image is mapped to an object. In this case, processing for associating pixels with texels, bilinear interpolation or the like is performed as texel interpolation.

  As the hidden surface removal processing, hidden surface removal processing by a Z buffer method (depth comparison method, Z test) using a Z buffer 179 (depth buffer) in which Z values (depth information and depth values) of drawing pixels are stored. It can be carried out. That is, when drawing pixels corresponding to the primitive of the object are drawn, the Z value stored in the Z buffer 179 is referred to. Then, the Z value of the referenced Z buffer 179 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 179 is updated to a new Z value.

α blending (α synthesis) is a translucent synthesis process (usually α blending, addition α blending, subtraction α blending, or the like) based on an α value (A value, transparency information). 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)

Here, R ₁ , G ₁ , B ₁ are RGB components of an image (original image) already drawn in the drawing buffer 174, and R ₂ , G ₂ , B ₂ should be drawn in the drawing buffer 174. 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, transparency information (equivalent to translucency information and opacity information), bump information, and the like.

  Further, in the present embodiment, the drawing unit 120 includes a determination unit 122.

  The determination unit 122 determines whether the value of the transparency information of the pixel corresponding to the object is within a given reference range. Specifically, it is determined whether or not the value (α value) of the transparency information of the drawing pixel is within the reference range stored in the object data storage unit 176.

  Further, the determination unit 122 may determine whether or not the value of the transparency information of the pixel corresponding to the object is within the reference range corresponding to the object stored in the object data storage unit 176.

  The determination unit 122 may determine whether the value of the pixel transparency information is within a reference range stored in association with the current virtual camera.

  When the determination unit 122 determines that the value of the transparency information is within the reference range, the drawing unit 120 draws the pixel information based on the transparency information without drawing the depth information (Z value) of the drawing pixel. Is drawn in the drawing buffer 174, and when the determination unit 122 determines that the value of the transparency information is not within the reference range, the pixel depth information is drawn in the Z buffer 179 (Z buffer 179). The Z value of the pixel is updated to the Z value of the pixel), and the color information of the pixel is drawn in the drawing buffer 174 based on the transparency information.

  The reference range changing unit (changing unit) 116 changes (updates) the reference range stored in the object data storage unit 176.

  The reference range changing unit 116 also stores the reference stored in the object data storage unit 176 based on the position of the virtual camera calculated by the virtual camera control unit 114 (virtual camera movement information stored in the object data storage unit 176). The range may be changed.

  The reference range changing unit 116 also stores the reference range stored in the object data storage unit 176 based on the position of the object calculated by the movement / motion processing unit 112 (object movement information stored in the object data storage unit 176). May be changed.

  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. 2. Method according to this embodiment FIG. 2 is a diagram for explaining a processing example according to this embodiment.

  In the example shown in FIG. 2, the image 210 is already drawn in the drawing buffer 174, and the region 222 (polygon) in the image 220 is drawn thereon, and further the region 242 (polygon) in the image 240 is drawn thereon. Processing to do.

  Here, the α value (transparency information) of the region 224 in the region 222 is in the range of 0.0 to 0.2 (the closer to the value 0.0, the more transparent, the closer to the value 1.0, the more opaque). The α value of the region 226 in the region 222 is a value in the range of 0.2 to 1.0, and the α value of the regions 212 and 242 is 1.0.

  Further, the Z value (depth information) of the area 212 is 1.0 (the closer to the value 0.0, the closer to the value, the closer to the value 1.0, the deeper the position), and the Z value of the area 242 is 0.5 and the Z value of region 222 is 0.0. That is, in the object space, the respective regions are located in the order of the region 212, the region 242, and the region 222 from the back as viewed from the virtual camera. In this example, a range of 0.0 to 0.2 (0.2 or less) is set as the reference range of the α value.

  The image 230 is an image obtained when the area 222 is drawn on the image 210 drawn in the drawing buffer 174. Here, since the Z value of the region 222 is smaller than the Z value of the region 212 in the image 210, the color of the region 222 is drawn on the image 210 in a portion overlapping the region 212. However, since the α value of the region 224 in the region 222 is small (high transparency), the color of the region 212 (close color) is drawn on the image 210 as the color of the region 224 as a result of the semi-transparent composition processing based on the α value. ing. Further, since the α value of the area 224 is within the reference range, the Z value of the area 224 is not drawn on the image 210, and only the Z value of the area 226 is drawn on the image 210. That is, the Z value of the region 232 in the image 230 is 0.0, and the Z value of the region 234 (region other than the region 232) is 1.0.

  The image 250 is an image obtained when the region 242 is drawn on the image 230 drawn in the drawing buffer 174. Here, since the Z value of the region 242 is smaller than the Z value of the region 234 in the image 230 and larger than the Z value of the region 232, the color of the region 242 is drawn on the image 230 in a portion overlapping the region 234. The color of the area 242 is not drawn in a portion overlapping the area 232.

  As described above, in the present embodiment, when drawing a polygon (object) including a translucent area, it is determined whether or not the α value of the area is in the reference range. Drawing is performed in the first drawing mode for drawing the information and the Z value, and if it is within the reference range, drawing is performed in the second drawing mode for drawing the color information without drawing the Z value.

  FIG. 3 is a processing example for comparison with the processing example of the present embodiment.

  The image 330 is an image obtained when the area 222 in the image 220 is drawn with respect to the image 210 drawn in the drawing buffer 174 only in the first drawing mode (a mode in which color information and a Z value are drawn). . Here, the Z value of the region 224 in the region 222 is drawn on the image 210 in the same manner as the Z value of the region 226. That is, the Z value of the area 332 in the image 230 is 0.0, and the Z value of the area other than the area 332 is 1.0.

  The image 350 is an image obtained when the region 242 in the image 240 is drawn with respect to the image 330 drawn in the drawing buffer 174. Here, since the Z value of the area 242 is larger than the Z value of the area 332 in the image 330, the color of the area 242 is not drawn on the image 330 in a portion overlapping the area 332. Therefore, in the image 350, the color of the region 242 is not drawn in the region 352, and the color of the region 212 that should be deeper than the region 242 remains, and is visually compared with the image 250 illustrated in FIG. 2. The image becomes unnatural.

  Thus, after drawing an object including a translucent area (area 222 in the image 220) and then drawing an object (area 242 in the image 240) located behind the virtual camera as viewed from the virtual camera, Although this may result in an unnatural image, according to the present embodiment, even in such a case, the processing load such as drawing after performing the process of sorting the objects in order from the object located at the back Appropriate drawing processing can be performed without applying.

  Next, a case where post-effect processing using the Z value (depth information) of the original image is performed on the image (original image) obtained by the processing of the present embodiment will be described. Here, a case where depth-of-field processing is performed on an image 230 (original image) shown in FIG. 2 obtained by drawing an object including a translucent region (region 222 in the image 220) will be described.

  When performing the depth of field process, first, the blurred image is generated by performing the blurring process on the original image. Next, a range for combining the blurred image is determined based on the Z value of the original image, and a process for combining the blurred image with the determined range of the original image is performed. At this time, a range in which the Z value is large (located in the back) is determined as a range in which the blurred image is synthesized.

  In the image 230 shown in FIG. 2, since the Z value of the region 232 is small (value 0.0) and the Z value of the region 234 is large (value 1.0), the region 234 (region 232) is used as a range for synthesizing the blurred image. Other areas) are determined. Therefore, when depth-of-field processing is performed on the image 230 shown in FIG. 2, the blurred image is combined with the region 234 (region other than the region 232) of the image 230, and is positioned closer to the front. An image is generated in which the region 232 is clearly visible and the region 234 located in the back is blurred.

  On the other hand, in the image 330 shown in FIG. 3 obtained by drawing the object including the translucent area (the area 222 in the image 220) only in the first drawing mode (the mode for drawing the color information and the Z value). Since the Z value of the region 332 is small (value 0.0) and the Z value of the region other than the region 332 is large (value 1.0), the region other than the region 332 is determined as a range in which the blurred image is synthesized. Therefore, when depth-of-field processing is performed on the image 330 shown in FIG. 3, the blurred image is synthesized in an area other than the area 332 of the image 330, so that the area 332 can be clearly seen and other than the area 332. An image in which the area is blurred is generated. Accordingly, only the portion that is not included in the region 332 of the portion of the image 330 in which the color of the region 212 (the region that is located behind the region 222) is drawn appears to be blurred, and the portion that is included in the region 332 is clearly visible. A visible image is generated, resulting in an unnatural image compared to the case where the depth of field processing is performed on the image 250 shown in FIG.

  As described above, according to the present embodiment, the post-effect process using the Z value of the original image is performed on the original image on which the object including the translucent area (the area 222 in the image 220) is drawn. Appropriate drawing processing can be performed.

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 object to be drawn is selected, and it is determined whether or not the object is a translucent object (step S10). Specifically, information indicating whether or not the object is a semi-transparent object is stored in the storage unit in association with each object, and the determination is performed with reference to the information.

  If it is determined in step S10 that the object to be drawn is a translucent object, one pixel among the pixels corresponding to the object is selected, and the Z value of the pixel and the Z value stored in the Z buffer are selected. To determine whether or not the Z value of the pixel is the Z value on the near side (step S12).

  If it is determined in step S12 that the Z value of the pixel is the near side Z value, whether the α value of the pixel is in the reference range with reference to the reference range stored in the storage unit It is determined whether or not (step S14). At this time, the reference range associated with the object being drawn may be referred to, or the reference range associated with the virtual camera used for drawing may be referred to. Further, the above determination may be made with reference to the reference range changed based on the position of the object, the position of the virtual camera, or the like.

  If it is determined in step S14 that the α value of the pixel is within the reference range, the process proceeds to step S18 without performing the process in step S16. If it is determined in step S14 that the α value of the pixel is not in the reference range, the Z value of the pixel is drawn in the Z buffer (the Z value of the Z buffer is updated to the value of the pixel) (step S16).

  Next, α blending processing is performed based on the α value of the pixel, and the obtained color information is drawn in the drawing buffer (step S18). Here, the color information and the α value of the pixel may be drawn in the drawing buffer.

  Next, it is determined whether or not processing has been performed for all pixels corresponding to the object being drawn (step S20), and if processing has not been performed for all pixels, the processing returns to step S12 and corresponds to the object. The next pixel to be selected is selected, and the processing from step S12 is repeated until the processing is completed for all the pixels corresponding to the object.

  If it is determined in step S20 that processing has been performed for all pixels, it is determined whether processing has been performed for all objects to be rendered (step S22), and processing has not been performed for all objects. Returns to step S10, selects the next object to be drawn, and repeats the processing from step S12 onward until the processing is completed for all objects.

  If it is determined in step S10 that the selected object is not a translucent object, one of the pixels corresponding to the object is selected, and the Z value of the pixel and the Z value stored in the Z buffer are obtained. In comparison, it is determined whether or not the Z value of the pixel is the Z value on the near side (step S24).

  If it is determined in step S24 that the Z value of the pixel is the near Z value, α blending processing is performed based on the α value of the pixel, and the obtained color information is drawn in the drawing buffer. The Z value of the pixel is drawn in the Z buffer (the Z value of the Z buffer is updated to the value of the pixel).

  Next, it is determined whether or not processing has been performed for all the pixels corresponding to the object being drawn (step S28). If processing has not been performed for all the pixels, the processing returns to step S24 and corresponds to the object. The next pixel to be selected is selected, and the processes in and after step S24 are repeated until the processing is completed for all the pixels. If it is determined that all pixels have been processed, the process proceeds to step S22.

  The present invention is not limited to the one 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 method of expressing the contact trace is not limited to that described in the present embodiment, and a method equivalent to these is also included in the scope of the present invention.

  The present invention can be applied to various games (racing game, fighting game, shooting game, robot battle game, sports game, competition game, role playing game, music playing game, dance game, 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. The flowchart which shows the process example of the game device of this embodiment.

Explanation of symbols

10 game device 100 processing unit 110 object space setting unit 112 movement / motion processing unit 114 virtual camera control unit 116 reference range changing unit 120 drawing unit 122 determination unit 140 sound generation unit 160 operation unit 170 storage unit 180 information storage medium 190 display unit 192 Sound output unit 194 Portable information storage device 196 Communication unit

Claims (8)

A program for generating an image visible from a virtual camera in an object space,
An object space setting section for setting an object in the object space;
A determination unit that determines whether or not a value of transparency information of a pixel corresponding to the object is in a given reference range;
When it is determined that the value of the transparency information is within the reference range, the pixel color information is drawn based on the transparency information without drawing the depth information of the pixel,
When it is determined that the value of the transparency information is not within the reference range, a drawing unit that draws the depth information of the pixel and draws the color information of the pixel based on the transparency information;
A program that causes a computer to function. In claim 1,
The program according to claim 1, wherein the reference range is a range including a value having the highest transparency and not including a value having the lowest transparency. In claim 1 or 2,
A storage unit for storing the reference range corresponding to the object;
Make your computer work,
The determination unit
A program for determining whether or not a value of the transparency information is within the reference range stored in the storage unit. In claim 3,
A changing unit for changing the reference range stored in the storage unit;
A program that causes a computer to function. In claim 4,
The changing unit is
A program for changing the reference range stored in the storage unit based on a position of a virtual camera in an object space. In claim 4,
The changing unit is
A program for changing the reference range stored in the storage unit based on a position of the object in an object space.   A computer-readable information storage medium, wherein the program according to any one of claims 1 to 6 is recorded. An image generation system for generating an image visible from a virtual camera in an object space,
An object space setting section for setting an object in the object space;
A determination unit that determines whether or not a value of transparency information of a pixel corresponding to the object is in a given reference range;
When it is determined that the value of the transparency information is within the reference range, the pixel color information is drawn based on the transparency information without drawing the depth information of the pixel,
When it is determined that the value of the transparency information is not within the reference range, a drawing unit that draws the depth information of the pixel and draws the color information of the pixel based on the transparency information;
An image generation system comprising: