JP4824514B2 - 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 that generates an image viewed from a virtual camera (a given viewpoint) in an object space (virtual three-dimensional space) in which moving objects such as cars, characters, and fighters are arranged and set ( Game system) is known, and is popular as a so-called virtual reality experience. Taking an image generation system capable of enjoying a racing game as an example, a player operates the own vehicle using an operation unit such as a game controller, and enjoys the game by competing with other vehicles operated by other players. .

  In such a racing game, it is desirable to be able to realistically express the surrounding light source and the background light reflected on the car window. Further, if the window can be seen and the state of a seat, a driver, and the like inside the car can be seen, the virtual reality of the player can be further improved.

However, the conventional image generation system has a problem that it is difficult to achieve both the light source reflection on the window and the reflection of light from the background and the transmission expression through which the inside of the vehicle can be seen.
JP 2001-325605 A

  The present invention has been made in view of the problems as described above, and an object of the present invention is to provide a program, an information storage medium, and an image generation system that can achieve both realistic reflection expression and transparent expression of a translucent object. It is to provide.

  The present invention is an image generation system for generating an image, which performs a lighting process on a translucent object and obtains a light reflection color of the translucent object, and the obtained reflection color of the translucent object An α value acquisition unit for obtaining an α value whose value changes according to the strength of the color, the color of the semi-transparent object, and the destination color that is the color of the drawing destination of the semi-transparent object. The present invention relates to an image generation system including an α blending unit that blends based on a value. The present invention also relates to a program that causes an image generation system to function as each of the above-described units, or a computer-readable information storage medium that stores the program.

  According to the present invention, the reflection color of the translucent object is obtained, and the α value whose value changes according to the intensity of the reflection color is obtained. Then, the color of the translucent object and the destination color are blended based on the obtained α value. In this way, the α value used for blending the color of the semi-transparent object and the destination color is different between the region (pixel) where the reflected color is strong and the region (pixel) where the reflected color is weak. This makes it possible to achieve both a realistic reflection expression and a transparent expression of a translucent object.

  In the image generation system, the program, and the information storage medium according to the present invention, the lighting processing unit obtains a specular color that is a reflected color by specular light based on an illumination model, and based on the obtained specular color, The reflection color of the semi-transparent object may be obtained, and the α value acquisition unit may obtain an α value whose value changes according to the intensity of the reflection color obtained from the specular color.

  In this way, the α value differs between the strong specular color area and the weak specular color area, and a realistic reflection expression of specular light can be realized.

  In the image generation system, the program, and the information storage medium according to the present invention, the lighting processing unit includes the translucent object based on a light source vector, a virtual camera line-of-sight vector, and a normal vector of the translucent object. The specular color may be obtained.

  In this way, the specular color changes according to the relationship between the light source vector, the line-of-sight vector, and the normal vector, whereby the α value also changes dynamically, and the realism of the image can be improved.

  The image generation system, the program, and the information storage medium according to the present invention further include a texture mapping unit that maps an environment texture representing the environment around the translucent object to the translucent object (a computer as the texture mapping unit) The lighting processing unit obtains the reflection color of the translucent object from the mapping color obtained by the environment mapping, and the α value acquisition unit obtains the reflection obtained by the mapping color of the environment mapping. You may make it obtain | require alpha value from which the value changes according to the strength of a color.

  In this way, the α value differs between a strong mapping area and a weak mapping color area that artificially express the specular color, and a reflection expression that effectively uses environment mapping can be realized.

  In the image generation system, the program, and the information storage medium according to the present invention, the α value acquisition unit calculates an α value that increases the blending rate of the color of the semitransparent object as the reflection color of the translucent object increases. In other words, the α blending unit may perform an α blending process in which the blending rate of the color of the semitransparent object with respect to the destination color increases as the reflection color of the translucent object increases.

  In this way, α blending is performed in which the blending rate of the color of the semi-transparent object is high in the region where the reflection color is strong, and the blending rate of the color of the semi-transparent object is low in the region where the reflection color is weak. Blending processing is performed, and α blending processing according to the strength of the reflected color can be realized.

  In the image generation system, the program, and the information storage medium according to the present invention, the α value acquisition unit is configured such that when the intensity parameter of the reflection color of the translucent object is SP and the material parameters are P1 and P2, α The α value may be obtained by an arithmetic expression of = P1 + P2 × SP.

  In this way, it is possible to control the default transparency of the translucent object by controlling the material parameter P1, for example.

  Further, in the image generation system, the program, and the information storage medium according to the present invention, the α value acquisition unit is based on the material parameters P1 and P2 set to different values according to the material of the translucent object. A value may be obtained.

  In this way, by changing the settings of the material parameters P1 and P2, it becomes possible to express translucent objects of various materials, and various image expressions are possible.

  The image generation system, the program, and the information storage medium according to the present invention further include a texture mapping unit that maps an environment texture representing the environment around the translucent object to the translucent object (a computer as the texture mapping unit) The mapping color of the translucent object is set in the color channel of the environment texture, and the α value of the environment texture has an α value whose value changes according to the strength of the mapping color. The α value acquisition unit may be set so as to obtain an α value whose value changes according to the intensity of the reflection color of the translucent object, which is the mapping color, by the environment mapping.

  In this way, since the α value can be acquired by effectively using environment mapping, the processing load can be reduced.

  In the image generation system, the program, and the information storage medium according to the present invention, the α blending unit includes at least the color of the translucent object determined based on the specular color, the diffuse color, and the ambient color, and the destination color. Alternatively, blending may be performed based on the obtained α value.

  The present invention is also an image generation system for generating an image, comprising: an object space setting unit that sets a plurality of objects including a moving body in an object space; and an operation for moving the moving body in the object space. A moving body calculation unit to perform, a virtual camera control unit to perform a virtual camera control process for generating an image that can be seen from a given viewpoint in the object space, and a reflected color by specular light based on an illumination model A lighting processing unit that obtains a specular color and obtains the reflection color of the window object of the moving object based on the obtained specular color, and the value changes according to the obtained intensity of the reflection color of the window object. An α value acquisition unit for obtaining an α value, a color of the window object, and an internal color of the moving body seen through the window object The present invention relates to an image generation system including an α blending unit that blends based on the obtained α value. The present invention also relates to a program that causes an image generation system to function as each of the above-described units, or a computer-readable information storage medium that stores the program.

  According to the present invention, the specular color that is the reflection color of the window object of the moving object that moves in the object space is obtained from the illumination model, and the α value whose value changes according to the intensity of the reflection color is obtained. Then, the color of the window object and the internal color of the moving object are blended based on the obtained α value. In this way, it is possible to achieve both a realistic reflection expression and a transparent expression of the window object of the moving object. In addition, as the moving body moves, the appearance of light changes in real time, and a realistic image that has never existed can be generated.

  The present invention is also an image generation system for generating an image, comprising: an object space setting unit that sets a plurality of objects including a moving body in an object space; and an operation for moving the moving body in the object space. A moving body computing unit that performs, a virtual camera control unit that performs a virtual camera control process for generating an image that can be viewed from a given viewpoint in the object space, and an environment texture that represents an environment around the moving body. A texture mapping unit that performs environment mapping on a moving object, a lighting processing unit that obtains a light reflection color of the window object of the moving object based on the mapping color obtained by the environment mapping, and the obtained reflection of the window object An α value acquisition unit for obtaining an α value whose value changes according to the strength of the color, the color of the window object, The present invention relates to an image generation system including an α blending unit that blends the internal color of the moving object that can be seen through the windowing object based on the obtained α value. The present invention also relates to a program that causes an image generation system to function as each of the above-described units, or a computer-readable information storage medium that stores the program.

  According to the present invention, the mapping color, which is the reflection color of the window object of the moving object moving in the object space, is obtained by environment mapping, and the α value whose value changes according to the strength of the reflection color is obtained. Then, the color of the window object and the internal color of the moving object are blended based on the obtained α value. In this way, it is possible to achieve both a realistic reflection expression and a transparent expression of the window object of the moving object. In addition, as the moving body moves, the appearance of light changes in real time, and a realistic image that has never existed can be generated.

  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 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, and the function can be realized by a direction key, operation buttons, analog stick, lever, steering, accelerator, brake, microphone, touch panel display, 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 (DRAM, VRAM) or the like. The storage unit 170 can be configured by a volatile memory that loses data when the power is turned off, but is a storage device that is faster than the auxiliary storage device 194. Then, the game program and game data necessary for executing the game program are held in the storage unit 170.

  An information storage medium 180 (a computer-readable medium) stores programs, data, and the like, and functions thereof by an optical disk (CD, DVD), HDD (hard disk drive), memory (ROM, etc.), and the like. realizable. 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, in the information storage medium 180, a program for causing a computer (an apparatus including an operation unit, a processing unit, a storage unit, and an output unit) to function as each unit of the present embodiment (a program for causing the computer to execute processing of each unit). Is memorized.

  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 auxiliary storage device 194 (auxiliary memory, secondary memory) is a large-capacity storage device that is used to supplement the capacity of the storage unit 170, and may be a memory card such as an SD memory card or a multimedia card, an HDD, or the like. realizable. The auxiliary storage device 194 is detachable, but may be built-in. The auxiliary storage device 194 is used for storing save data such as game results, personal image data and music data of the player (user).

  The communication unit 196 communicates with the outside (for example, another image generation system, a server, or a host device) via a wired or wireless network, and functions as a communication ASIC, a communication processor, or the like. It can be realized by hardware and communication firmware.

  Note that a program (data) for causing a computer to function as each unit of the present embodiment is obtained from an information storage medium of a server (host device) via an information storage medium 180 (or storage unit 170, auxiliary storage) via a network and communication unit 196. May be distributed to the device 194). Use of an information storage medium by such a server (host device) can also be included in the scope of the present invention.

  The processing unit 100 (processor) performs game processing, image generation processing, sound generation processing, and the like based on operation data from the operation unit 160, a program, and the like. The processing unit 100 performs various processes using the storage unit 170 (main storage unit 172) as a work area. The functions of the processing unit 100 can be realized by hardware such as various processors (CPU, GPU, etc.), ASIC (gate array, etc.), and programs.

  The processing unit 100 includes a game calculation unit 108, an object space setting unit 110, a moving body calculation unit 112, a virtual camera control unit 114, an image generation unit 120, and a sound generation unit 130. Note that some of these may be omitted.

  The game calculation unit 108 performs game calculation processing. Here, the game calculation includes 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 moving object or a map, a process for displaying an object, and calculating a game result. Or a process for ending the game when a game end condition is satisfied.

  The object space setting unit 110 displays various display objects such as model objects (moving bodies such as cars, fighters, people, robots, missiles, and bullets), maps (terrain), buildings, courses (roads), trees, and walls. Processing for setting an object (an object composed of a primitive surface such as a polygon, a free-form surface, or a subdivision surface) in the object space is performed. 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. Specifically, model data such as a moving object (car, fighter, character) is stored in the model data storage unit 176 of the storage unit 170. Then, the object space setting unit 110 performs an object setting (arrangement) process in the object space using the model data.

  The moving object calculation unit 112 performs an operation for moving the moving object (moving object). Also, calculations for operating the moving body are performed. That is, based on operation data input by the player through the operation unit 160, a program (movement / motion algorithm), various data (motion data), etc., a moving body (object, model object) is moved in the object space, Performs processing to move the moving body (motion, animation). Specifically, a simulation process for sequentially obtaining movement information (position, rotation angle, speed, or acceleration) and motion information (part object position or rotation angle) of a moving body for each frame (1/60 second). I do. A frame is a unit of time for performing a moving / movement process (simulation process) and an image generation process of a moving object.

  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 a moving body such as a car, character, or fighter is photographed from behind using a virtual camera, the position or rotation angle of the virtual camera (virtual camera is set so that the virtual camera follows changes in the position or rotation of the moving body. The direction). In this case, the virtual camera can be controlled based on information such as the position, rotation angle, or speed of the moving object obtained by the moving object computing 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.

  Note that the mobile body of the present embodiment may be a mobile body operated by the player, or a mobile body operated (controlled) by another player or computer. Further, the image generated according to the present embodiment may be a normal game image whose image is changed by the game play of the player, or may be a replay image, an opening image, or an ending image displayed outside the game. Good.

  The image generation unit 120 performs drawing processing based on the results of various processes (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, model data including vertex data (vertex position coordinates, texture coordinates, color data, normal vector, α value, etc.) of each vertex of the model (object) is first input. Based on the vertex data included in the input model data, vertex processing (shading by a vertex shader) is performed. 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 vertex processing (vertex shader processing), vertex movement processing, coordinate transformation (world coordinate transformation, camera coordinate transformation), clipping processing, perspective transformation, etc. according to a vertex processing program (vertex shader program, first shader program) Geometry processing is performed, and based on the processing result, the vertex data given to the vertex group constituting the object is changed (updated, 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 (pixel shader processing), according to the pixel processing program (pixel shader program, second shader program), various processes such as texture reading (texture mapping), color data setting / changing, translucent composition, anti-aliasing, etc. The final drawing color of the pixels constituting the image is determined, and the drawing color of the perspective-converted model is output to the drawing buffer 174 (buffer that can store image information in units of pixels; VRAM, rendering target) (drawing) ) 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.

  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 image generation unit 120 includes a lighting processing unit 122, a texture mapping unit 124, an α value acquisition unit 126, and an α blending unit 128. Note that some of these may be omitted.

  The lighting processing unit 122 performs lighting processing (shading processing) based on an illumination model or the like. Specifically, this lighting processing includes light source information (light source vector, light source color, brightness, light source type, etc.), line-of-sight vector of virtual camera (viewpoint), normal vector of object (translucent object), object material ( Color, material) and the like. Illumination models include the Lumbard diffuse lighting model that considers only ambient light and diffuse light, the phone lighting model that considers specular light in addition to ambient light and diffuse light, and the Bling phone lighting model. is there.

  The texture mapping unit 124 performs processing for mapping a texture to an object (polygon). Here, the texture mapping process is a process of mapping a texture (texel value) stored in the texture storage unit 178 to an object. Specifically, the texture (surface properties such as color and α value) is read from the texture storage unit 178 using the texture coordinates set (given) to the vertices and pixels of the object (primitive surface). Then, a texture that is a two-dimensional image or pattern is mapped to the object. In this case, processing for associating pixels and texels, bilinear interpolation (texel interpolation), and the like are performed.

  The α value acquisition unit (α value calculation unit) 126 performs a process of acquiring (calculating) an α value for α blending. Here, 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 translucency (equivalent to transparency and opacity) information, mask information, or bump information.

  The α blending unit 128 performs α blending processing (color synthesis processing, translucent synthesis processing) based on the α value. Here, α blending processing includes normal α blending, addition α blending, subtraction α blending, and the like. For example, in the case of normal α blending, the following processing is performed.

R _Q = (1−α) × R _D + α × R _S
G _Q = (1−α) × G _D + α × G _S
B _Q = (1−α) × B _D + α × B _S
On the other hand, in the case of addition α blending, the following processing is performed.

R _Q = R _D + α × R _S
G _Q = G _D + α × G _S
B _Q = B _D + α × B _S
In the case of subtractive α blending, the following processing is performed.

R _Q = R _D −α × R _{S
G Q = G D -α × G} S
B _Q = B _D -α × B _S
Here, R _D , G _D , and B _D are color components (destination colors) of an image (original image) already drawn in the drawing buffer 174 (frame buffer, color buffer), and R _S , G _S , B _S are color components (source colors) of the image to be drawn in the drawing buffer 174. R _Q , G _Q , and B _Q are color components (final colors) of the image obtained by the α blending process.

  In this embodiment, the lighting processing unit 122 performs lighting processing of a semi-transparent object such as a window object, and obtains a light reflection color (specular color or pseudo-specular color) of the semi-transparent object. Specifically, the lighting processing unit 122 obtains a specular color based on the illumination model, and obtains a reflection color of the translucent object based on the obtained specular color. Alternatively, the texture mapping unit 124 maps the environment texture representing the environment (surrounding image) around the translucent object to the translucent object. Then, the lighting processing unit 122 obtains the reflection color of the translucent object based on the mapping color obtained by the environment mapping.

  Then, the α value acquisition unit 126 changes its value according to the strength (brightness, intensity, power) of the obtained reflection color (for example, reflection color excluding diffuse color and ambient color) of the translucent object. Find the alpha value to be Specifically, the intensity of the reflection color of the semi-transparent object is obtained, and the α value at which the blending rate of the color of the semi-transparent object (source color) increases as the reflection color becomes stronger. Alternatively, an α value whose value changes according to the strength (brightness) of the mapping color is set in the α channel (α plane) of the environmental texture stored in the texture storage unit 178. Then, the α value acquisition unit 126 may acquire an α value whose value changes according to the strength of the reflection color of the translucent object that is the mapping color by the environment mapping by the environment mapping unit 124.

  Then, the α blending unit 128 determines the color of the semi-transparent object (source color) and the destination color (color drawn in the drawing buffer 174) that is the drawing destination color of the semi-transparent object based on the α value. Blend. Specifically, the color of the translucent object obtained based on at least the specular color, the diffuse color, and the ambient color and the destination color are blended based on the α value obtained by the α value acquisition unit 126. .

  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 of Present Embodiment 2.1 Window Representation In FIG. 2A, a mobile object MOB representing a car is provided with a translucent object WOB representing a car windshield window. In the following, a case where the moving body is a car and the translucent object is a window object will be described as an example. However, the present embodiment is not limited to this. For example, the moving body is not limited to a car, and may be a fighter, a train, a robot, or the like. The translucent object is not limited to a window object, and may be a water surface object, for example.

  In FIG. 2A, in order to improve the player's virtual reality, it is desirable that the light source LS and the background light reflection on the window can be realistically expressed. In addition, it is desirable to be able to realize a transparent expression in which the window can be seen and the inside of the moving body MOB can be seen.

  However, the conventional image generation systems have a problem that it is difficult to achieve both the expression of the reflection of the light source and the background light in the window and the transmission expression inside the moving object through the window.

  For example, in FIG. 2B, the source color CS is the color of the translucent object WOB representing the window (object color, reflection color, material color), and the destination color CD is the color of the drawing destination of the translucent object WOB ( Drawing buffer color).

  The reflection expression of the light source and background light on the window is obtained, for example, based on an illumination model (model arithmetic expression, light source information, normal information, virtual camera information), and the reflected color of light of the translucent object WOB is obtained. This can be realized by obtaining the color CS of the window object WOB based on the obtained reflection color.

  On the other hand, the transparent expression inside the moving object through the window can be realized by blending the color CS of the translucent object WOB and the CD which is the color of the sheet or driver inside the moving object based on the α value.

  In this case, for example, in order to express a transparent window with high transparency, the α value that is the blending rate of the color CS of the translucent object WOB may be reduced. Thus, if the α value is reduced and the transmittance of the window is increased, the interior can be clearly seen through the window of the car, and the realism of the image can be increased.

  However, if the α value is decreased, the blending rate of the color CS of the translucent object WOB is decreased. Accordingly, not only the color as the window material, but also the blending rate of the reflected color due to the reflection of the light source and the environment is reduced, and the reflected image of the light source and the environment becomes thin and becomes inconspicuous. As a result, it is not possible to express a realistic image in which the light source and environment are reflected strongly on the transparent window glass, and the virtual reality of the player is insufficiently improved.

2.2 Control of α value by intensity of reflected color In order to solve such a problem, in the present embodiment, a method of controlling the α value according to the intensity (brightness) of the reflected color of the translucent object WOB. Is adopted.

  For example, in FIGS. 3A and 3B, the lighting processing of the translucent object WOB is performed, and the reflection color of the WOB light (for example, the reflection color excluding the diffuse color and the ambient color) is obtained. Then, the α value is changed according to the obtained intensity of the reflected color.

  For example, when the reflection color of the translucent object WOB is weak as shown in FIG. 3A (when intensity and specular power are small), the α value corresponding to the blending rate of the color CS with respect to the color CD is reduced. On the other hand, when the reflection color of the translucent object WOB is strong as shown in FIG. 3B (when intensity and specular power are large), the α value is increased. In this way, it is possible to realize an α blending process in which the blending rate of the color CS of the translucent object WOB with respect to the color CD increases as the reflection color (specular color) of the translucent object WOB increases. As a result, it is possible to realize an expression in which a light source and an environment are reflected in a realistically reflected window.

  That is, in FIG. 3A, since the reflected color of light at the pixel PXA is weak, the α value at PXA is small. Accordingly, the blending rate of the color CS is also reduced, and the color CS of the translucent object WOB is lightened in the pixel PXA, so that the lower color CD can be seen well. Therefore, in the pixel PXA, the inside of the moving body can be clearly seen through the transparent window.

  On the other hand, in FIG. 3B, since the reflected color of light at the pixel PXB is strong, the α value at PXB is large. Accordingly, the blending rate of the color CS is also increased, and the color CS of the translucent object WOB is darker than the lower color CD of the pixel PXB. Therefore, in this pixel PXB, the reflection of the light source and the environment can be clearly seen.

  For example, FIGS. 4 and 5 show examples of images generated by this embodiment. FIG. 4 is an example of an image when the reflected color of light from a car window is weak and the reflection of a light source or environment is weak. In FIG. 4, an image is generated in which there is no reflection on the window and the state of the seat inside the vehicle and the driver can be clearly seen through the transparent window.

  On the other hand, FIG. 5 is an example of an image when the reflected color of light from a car window is strong and the reflection of a light source or environment is strong. In FIG. 5, an image in which the light source and the environment are reflected strongly in the window is generated, and a real image close to the real world has been successfully generated.

  According to the present embodiment, for example, when a car that is a moving body moves, the positional relationship between the car, the virtual camera, the light source, and the surrounding environment changes, and the intensity of the reflected color of light with respect to the window changes, Correspondingly, the light source and the reflection of the environment on the window also change in real time. For example, when the positional relationship among the car, virtual camera, light source, and environment is the first positional relationship, an image as shown in FIG. 4 is generated, and when the positional relationship is the second positional relationship, FIG. An image as shown is generated. Accordingly, the reflected image of the window changes in real time due to the change in the positional relationship, so that an unprecedented realistic image can be generated.

2.3 Lighting Processing by Lighting Model Next, a specific example of how to obtain the reflected color by lighting processing will be described. As a mathematical model for simulating an illumination phenomenon in the real world, various illumination models are used in this type of image generation system. FIGS. 6A and 6B show examples of illumination models when the light source is parallel light.

  FIG. 6A is a diagram for explaining the lighting model of the phone, and this lighting model is represented by the following equation (1).

I = _Ksp * (L * R) ⁿ * _Isp + _Kdf * (N * L) * _Idf + _Kam * _Iam (1)
Here, K _sp , K _df , and K _am are reflectances (object colors) for specular light, diffuse light, and ambient light, respectively, and I _sp , I _df , and I _am are specular light and diffuse light, respectively. It is the brightness (intensity, light source color) of light and ambient light. N is a normal vector of an object (moving object, window object), L is a vector of a light source (parallel light source) LS, R is a reflection vector, and R = −E + 2 (N · E) N Can do. n is a specular reflection index (highlight characteristic coefficient).

  In this Phong illumination model, the intensity of specular light is expressed as the power of the inner product of the light vector L and the reflection vector R. Therefore, the specular light becomes stronger as the direction of the light vector L and the reflection vector R becomes closer. When the specular reflection index n is as small as 10 or less, for example, the specular reflection highlight spreads over a wide range, and when the specular reflection index P is as large as about 100, the highlight becomes a small point.

  FIG. 6B is a diagram for explaining an illumination model of Brin Fong, and this illumination model is expressed by the following equation (2).

I = _Ksp * (N * H) ⁿ * _Isp + _Kdf * (N * L) * _Idf + _Kam * _Iam (2)
Here, H is a half vector and can be expressed as H = (E + L) / | E + L |.

  In the Brin von lighting model, the intensity of specular light is expressed by the power of the inner product of the normal vector N and the half vector H. Accordingly, the specular light becomes stronger as the direction of the normal vector N and the half vector H becomes closer.

  In the present embodiment, a specular color, which is a reflected color by specular light, is obtained based on the illumination model as shown in the above formulas (1) and (2), and the reflection of the translucent object is based on the obtained specular color. Find the color. Then, an α value whose value changes according to the intensity of the reflected color obtained from the specular color is obtained.

For example, in the phone lighting model of the above equation (1), the specular color is obtained as C _sp = K _sp × (L · R) ⁿ × I _sp . Further, in the Brin von illumination model of the above formula (2), the specular color is obtained as C _sp = K _sp × (N · H) ⁿ × I _sp . That is, the specular color _Csp is obtained based on the light source vector L, the line-of-sight vector E of the virtual camera VC, and the normal vector N of the translucent object (moving body).

Then, based on the specular color _{C sp} obtained, reflection color strength parameter SP = F in (specular color) _{(C sp)} is determined on the basis of the strength parameter SP, alpha value alpha = G (SP) Is required. Note that F represents a predetermined function with C _sp as an argument, and G represents a predetermined function with SP as an argument.

  Thus, if the specular color is obtained based on the illumination model and the α value is obtained based on the specular color, the α value can be changed according to the strength of the specular color. Therefore, for example, an expression in which the α value is small in a region where specular reflection of specular light is weak, while an α value is large in a region where specular reflection of specular light is strong is possible. As a result, a realistic image representation of the specular light reflected on the transparent window glass becomes possible.

  The illumination model used in this embodiment is not limited to the above formulas (1) and (2). For example, an illumination model that is mathematically substantially equivalent to the above equations (1) and (2) may be used, or brightness correction or the like may be performed on the illumination models of the above equations (1) and (2). Alternatively, an illumination model represented by an expression different from the above expressions (1) and (2) may be used.

2.4 Lighting Processing by Environment Mapping In FIG. 7A, environment mapping is used to express the reflection of background light on the mobile MOB. Specifically, an environment mapping is performed on an image of a cube object COB (environment mapping object in a broad sense) with respect to a moving body MOB that moves in an object space as an environment texture. FIG. 8 shows an example of an environment texture when cube environment mapping is used.

  For example, in FIG. 7A, the virtual camera VC moves following the moving body MOB, and an image of the moving body MOB is displayed in an image seen from the virtual camera VC. At this time, a background image when the surroundings are looked around by the virtual camera VC is drawn inside the cube object COB, and this background image is mapped to the moving body MOB as an environmental texture. In this way, the environment texture representing the surrounding environment can be mapped to the window (semi-transparent object) of the moving object MOB, and the reflection of background light on the window can be realized. Then, the reflection color of the window is obtained from the mapping color obtained by such environment mapping, and the α value is changed according to the obtained intensity of the reflection color.

  In this way, the reflection of background light on the window changes in real time in accordance with the positional relationship between the moving object MOB, the virtual camera VC, and the like. That is, when there is a positional relationship with less reflection, an image as shown in FIG. 4 is generated, and when there is a positional relationship with more reflection, an image as shown in FIG. 5 is generated. In addition, realistic reflection expression can be realized.

  For example, in the method using the illumination model shown in FIGS. 6A and 6B, only reflection due to specular reflection of a parallel light source can be expressed. On the other hand, in the method using the environment mapping in FIG. 7A, it is possible to express the reflection of light in the surrounding complicated background. That is, as shown in FIG. 5, it is possible to realize a realistic expression in which a bright portion of the background is reflected on a transparent window glass through which the interior of the vehicle can be seen.

  The environment mapping in FIG. 7A can be realized by the following method. That is, in FIG. 7A, a normal vector N is set for each point (vertex, pixel, surface) of the moving object MOB. In this case, for example, the light reflection vector R is obtained based on the line-of-sight vector and the normal vector N of the virtual camera VC. Then, the environment texture is fetched using the reflection vector R. Specifically, based on, for example, the X and Y coordinates (or the X and Y coordinates after coordinate conversion) of the reflection vector R, texture coordinates U and V for environment mapping are obtained by a predetermined arithmetic expression. Based on the obtained texture coordinates U and V, an image (environmental texture) of the cube object COB is sampled and mapped to the moving object MOB. In this way, it is possible to map a reflected image that changes realistically according to the positional relationship between the mobile object MOB and the virtual camera VC to the mobile object MOB.

  Although FIG. 7A shows an example of cube environment mapping, the environment mapping according to the present embodiment is not limited to such cube environment mapping, and includes sphere environment mapping, paraboloid environment mapping, cylinder environment mapping, and the like. There may be. In addition, as shown in FIG. 7B, the expression of specular reflection by specular light is realized by reflection mapping using a reflection map texture that becomes brighter as it approaches the center of the circle and becomes darker as it moves away from the center of the circle. Also good.

2.5 Calculation of α Value Next, a specific calculation method of the α value will be described. For example, in FIGS. 9A and 9B, when the intensity parameter (brightness parameter) of the reflection color of the translucent object WOB is SP and the material parameters are P1 and P2, these parameters SP, The α value is obtained by an arithmetic expression using P1 and P2. For example, the intensity parameter of the reflected color can be obtained by an arithmetic expression such as the following expression.

_{SP = F (C sp) =} K 1 × R sp + K 2 × G sp + K 3 × B sp (3)
Here, as K ₁ , K ₂ , and K ₃ , coefficients that convert RGB components into Y components in RGB-YUV conversion can be used. For example, K ₁ = 0.299, K ₂ = 0.587, K is a ₃ = 0.114. Thereby, the intensity (brightness and luminance) of the reflected color can be extracted.

  Further, the α value can be obtained by an arithmetic expression such as the following expression.

α = G (SP) = P1 + P2 × SP (4)
Here, the material parameter P1 is a parameter representing the default transparency of the translucent object WOB, and the material parameter P2 is a conversion coefficient parameter of reflected color intensity-α value.

  In this embodiment, the α value is obtained based on the material parameters P1 and P2 set to different values depending on the material (type and material) of the translucent object WOB.

  For example, in FIG. 9A, the material parameter P1 is set to a small value, and thereby, transparent glass with high transparency can be expressed. On the other hand, in FIG. 9B, the material parameter P1 is set to a large value, and thereby, a cloudy glass (smoke glass) with low transparency can be expressed. For example, when P1 = 0 is set, α = 0 is set in the portion where the reflected color is not reflected, and the lower color CD can be completely seen through. On the other hand, when P1 is increased, α = P1 even in a portion where the reflected color is not reflected, so that the lower color CD can be seen through the translucent portion. In addition, the larger the material parameter P2 is set, the greater the difference between the transparency in the portion where the reflection color is strong and the transparency in the portion where the reflection color is weak.

  Thus, if the α value is obtained by the above equation (4), the semi-transparent object WOB of various materials can be expressed by controlling the material parameters P1 and P2, and various processing loads can be achieved with a small processing load. Image representation can be realized. Further, for example, if the material parameters P1 and P2 are changed in real time in accordance with the result of the game processing, animation expression can be realized, and various image expressions can be realized.

  The α value acquisition method is not limited to the method using the above equations (3) and (4). For example, the intensity of reflected light may be obtained by an arithmetic expression different from the above expression (3) (for example, an expression having a different coefficient, order, or function), or an arithmetic expression different from the above expression (4) (for example, an order). Alternatively, the α value may be obtained by an equation having a different order or function form. It is also possible to directly obtain the α value based on the normal vector, the line-of-sight vector, the light source vector, etc. without obtaining the intensity of the reflected light.

Alternatively, the α value may be acquired by effectively using environment mapping. For example, in FIG. 10, the mapping color _{Cmp of the} translucent object is set in the color channel (color plane, color texel) of the environmental texture. On the other hand, an α value whose value changes according to the strength (brightness) of the mapping color C _mp is set in the α channel (α plane, α texel) of the environment texture. That is, an α value is set such that the higher the mapping color C _mp is, the higher the blending rate of the color of the translucent object is.

In this way, it is possible to acquire an α value whose value changes according to the intensity of the reflection color of the translucent object, which is the mapping color _Cmp , using environment mapping. That is, when the reflection color is obtained by environment mapping as shown in FIG. 7A, the α value can also be fetched at the time of fetching the mapping color _Cmp that becomes the reflection color. Accordingly, calculations such as the above formulas (3) and (4) are not required, and the α value can be acquired by effectively using environment mapping, so that the processing load can be reduced.

2.6 Calculation of α Value According to Specular Color Strength In FIG. 11, the α value is calculated according to the intensity of the specular color excluding the diffuse color and the ambient color among the reflected colors.

Specifically, the specular color C _sp ′ based on the illumination model is obtained by the method described in FIGS. 6 (A) and 6 (B). Further, the mapping color _Cmp of the environment mapping is obtained as a pseudo specular color by the method described with reference to FIG. The 'by _{C mp,} specular color _C sp _{= C sp} used to calculate α value' _{C sp} seek _{+ C mp.}

Further, the diffuse color C _df and the ambient color C _am are obtained using an illumination model (for example, a Lumbard diffuse illumination model). For example, the diffuse color C _df and the ambient color C _am can be obtained by the following illumination model.

I = K _df × (N · L) × I _df + K _am × I _am (5)
Then, the color CS (source color) of the translucent object can be obtained from the specular color C _sp , diffuse color C _df , and ambient color C _am obtained as described above, as shown in the following equation.

CS = C _sp + C _df + C _am (6)
Color CS of such translucent object is determined based on at least specular color _{C sp} and diffuse color _{C df} and ambient color _{C am.}

  The final color CQ can be obtained by the following equation by α blending the source color CS and the diffuse color CD based on the α value.

CQ = (1-α) × CD + α × CS (7)
At this time, the α value is obtained from the specular color C _sp = C _sp ′ + C _mp as indicated by A1 in FIG. Specifically, the intensity parameter SP = F (C _sp ) of the specular color C _sp (reflection color in a broad sense) is obtained, and the α value α = G (SP) is obtained from the intensity parameter SP.

In this way 11 obtains the specular color C _sp excluding diffuse color C _df and ambient color C _am of the reflected light, and changing the α value according to the strength of the specular color C _sp. In this way, a more realistic reflection expression for a semi-transparent object can be realized. That is, when the diffuse color C _df and the ambient color C _am are used for obtaining the α value, the color of the material affects the α value. For example, in the case of a white translucent object, the α value becomes large even in an area where the reflection of light is not strong, and it becomes difficult to express realistic reflection. In contrast, by changing the α value according to the strength of the specular color C _sp, in reflection is strong region of the light becomes large α value, in reflection of the light is weak region does not become α value is larger Therefore, a more realistic reflection expression on the translucent object can be realized. Therefore, in order to improve the real degree of the image, a technique of changing the α value according to the strength of the specular color C _sp as shown in FIG. 11 is desirable.

2.7 Detailed Processing Example Next, a detailed processing example of the present embodiment will be described with reference to the flowcharts of FIGS.

  First, an object space setting process for arranging and setting a plurality of objects including a moving object in the object space is performed (step S1). Next, a moving body calculation process for moving a moving body such as a car in the object space is performed (step S2). Specifically, based on operation data from the operation unit 160, a program, and the like, a change in the position of the moving body, a change in direction, and a change in operation for each frame are calculated in real time.

  Next, vertex shader processing by the vertex shader program is performed (step S3). Vertex coordinates, line-of-sight vectors, light source vectors, normal vectors, and the like obtained by this vertex shader processing are stored in an output register and passed to pixel shader processing.

  Next, pixel shader processing by the pixel shader program is started (step S4). By this pixel shader process, the processes of steps S5 to S12 are performed.

Specifically, first, as described with reference to FIGS. 6A and 6B, the specular color C _sp ′ is obtained based on the light source vector L, the line-of-sight vector E, and the normal vector N (step S5). ). Further, as described with reference to FIG. 7A, environment mapping is performed and the mapping color _Cmp is fetched (step S6). Then, the specular color C _sp = C _sp '+ C _mp is obtained (step S7).

Then determine the specular color _C strength parameter of _{sp SP = F (C sp)} = K 1 × R sp + K 2 × G sp + K 3 × B sp ( step S8). Then, α = G (SP) = P1 + P2 × SP is obtained based on the material parameters P1 and P2 and the strength parameter SP (step S9).

Next, the diffuse color C _df and the ambient color C _am are obtained based on the illumination model (step S10). Then, based on the specular color C _sp , the diffuse color C _df , and the ambient color C _am , the color CS = C _sp + C _df + C _am of the translucent object is obtained (step S11). Then, the color CS and the destination color CD are blended based on the α value obtained in step S9 to obtain a final color CQ = (1−α) × CD + α × CS (step S12).

FIG. 13 is a flowchart of processing for realizing the method of FIG. In steps S21 to S25, processing similar to that in steps S1 to S5 in FIG. 12 is performed. Next, environment mapping is performed to fetch not only the mapping color C _mp but also the α value (step S26). This α value is an α value that changes in accordance with the strength of the mapping color _Cmp .

Next, the specular color C _sp = C _sp ′ + C _mp is obtained (step S27). In FIG. 13, steps S8 and S9 in FIG. 12 are omitted. In steps S28 to S30, processing similar to that in steps S10 to S12 in FIG. 12 is performed. In this case, in step S30, α blending processing is performed based on the α value fetched by the environment mapping in step S26.

3. Hardware Configuration FIG. 14A shows a hardware configuration example that can realize the present embodiment.

  The CPU 900 (main processor) is a multi-core processor including a plurality of CPU cores 1, CPU cores 2, and CPU cores 3. The CPU 900 includes a cache memory (not shown). Each of the CPU cores 1, 2, and 3 is provided with a vector calculator and the like. Each of the CPU cores 1, 2, and 3 can execute, for example, two H / W thread processes in parallel without performing a context switch, and a multi-thread function is supported by hardware. A total of three CPU cores 1, 2, and 3 can execute six H / W thread processes in parallel.

  The GPU 910 (drawing processor) performs vertex processing and pixel processing to realize drawing (rendering) processing. Specifically, according to the shader program, the vertex data is created / changed and the drawing color of the pixel (fragment) is determined. When an image for one frame is written into the VRAM 920 (frame buffer), the image is displayed on a display such as a TV via a video output. The main memory 930 functions as a work memory for the CPU 900 and the GPU 910. Further, in the GPU 910, a plurality of vertex threads and a plurality of pixel threads are executed in parallel, and a multi-thread function of drawing processing is supported by hardware. The GPU 910 is also provided with a hardware tessellator. The GPU 910 is a unified shader type in which the vertex shader and the pixel shader are not distinguished in terms of hardware.

  The bridge circuit 940 (south bridge) is a circuit that controls the flow of information inside the system, and includes a controller such as a USB controller (serial interface), a network (Ethernet (registered trademark)) communication controller, an IDE controller, or a DMA controller. Built in. The bridge circuit 940 implements an interface function among the game controller 942, the memory card 944, the HDD 946, and the DVD drive 948.

  Note that the hardware configuration capable of realizing this embodiment is not limited to FIG. 14A, and may be, for example, a configuration as shown in FIG.

  In FIG. 14B, the CPU 902 includes a processor element PP and eight processor elements PE1 to PE8. The processor element PP is a general-purpose processor core, and the processor elements PE1 to PE8 are processor cores having a relatively simple configuration. The architectures of the processor element PP and the processor elements PE1 to PE8 are different, and the processor elements PE1 to PE8 are SIMD type processor cores that can simultaneously perform the same processing on a plurality of data with one instruction. Thereby, multimedia processing such as streaming processing can be executed efficiently. The processor element PP can execute two H / W thread processes in parallel, and each of the processor elements PE1 to PE8 can execute one H / W thread process. Therefore, the CPU 902 can execute a total of 10 H / W thread processes in parallel.

  In FIG. 14B, the GPU 912 and the CPU 902 are closely linked, and the GPU 912 can directly perform the rendering process on the main memory 930 on the CPU 902 side. Further, for example, the CPU 902 can perform geometry processing to transfer vertex data, or easily return data from the GPU 912 to the CPU 902. It is also easy for the CPU 902 to perform rendering pre-processing and post-processing, and the CPU 902 can execute tessellation (plane division) and dot fill. For example, the CPU 902 can perform a process with a high level of abstraction, and the GPU 912 can perform a detailed process with a low level of abstraction.

  When the processing of each unit of the present embodiment is realized by hardware and a program, a program for causing the hardware (computer) to function as each unit of the present embodiment is stored in the information storage medium. More specifically, the program instructs a processor (CPU, GPU), which is hardware, to pass data if necessary. And a processor implement | achieves the process of each part of this invention based on the instruction | indication and the passed data.

  Although the present embodiment has been described in detail as described above, it will be easily understood by those skilled in the art that many modifications can be made without departing from the novel matters and effects of the present invention. Accordingly, all such modifications are intended to be included in the scope of the present invention. For example, a term (cube object, specular color, etc.) written together with a different term (environment mapping object, reflection color, etc.) in a broader or synonymous manner at least once in the specification or drawing is used anywhere in the specification or drawing. Can also be replaced by the different terms.

  Also, the lighting process, the environment mapping process, the α value acquisition process, and the α blending process are not limited to those described in this embodiment, and techniques equivalent to these are also included in the scope of the present invention. The present invention can be applied to various games. 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 game images, and a mobile phone. it can.

The example of the block diagram of the image generation system of this embodiment. FIG. 2A and FIG. 2B are explanatory diagrams of light reflection expression on a car window. 3A and 3B are explanatory diagrams of a method for controlling the α value based on the intensity of the reflected color. The example of the image produced | generated by this embodiment. The example of the image produced | generated by this embodiment. 6A and 6B are explanatory diagrams of a specular illumination model. 7A and 7B are explanatory diagrams of environment mapping and reflection mapping. Example of environmental texture. 9A and 9B are explanatory diagrams of an α value calculation method. Explanatory drawing of the method of using alpha value set to alpha channel of environmental texture. Explanatory drawing of the method of changing (alpha) value according to the intensity of a specular color. The flowchart explaining the detailed process of this embodiment. The flowchart explaining the detailed process of this embodiment. FIG. 14A and FIG. 14B are hardware configuration examples.

Explanation of symbols

100 processing unit, 108 game calculation unit, 110 object space setting unit,
112 moving body calculation unit, 114 virtual camera control unit, 120 image generation unit,
122 lighting processing unit, 124 texture mapping unit, 126 α value acquisition unit,
128 α blending unit, 130 sound generation unit, 160 operation unit, 170 storage unit,
172 Main storage unit, 174 drawing buffer, 176 model data storage unit,
178 texture storage unit, 180 information storage medium, 190 display unit, 192 sound output unit,
194 Auxiliary storage device, 196 communication unit

Claims (15)

A lighting processing unit that performs lighting processing of the translucent object and obtains a light reflection color of the translucent object;
An α value obtaining unit for obtaining an α value whose value changes according to the intensity of the reflected color of the obtained translucent object;
As an α blending unit that blends the color of the semi-transparent object and the destination color that is the drawing destination color of the semi-transparent object based on the obtained α value,
Make the computer work ,
The α value acquisition unit
A program for obtaining an α value by an arithmetic expression of α = P1 + P2 × SP, where SP is a reflection color intensity parameter of the translucent object and P1 and P2 are material parameters . In claim 1 ,
The α value acquisition unit
A program for obtaining an α value based on the material parameters P1 and P2 set to different values depending on the material of the translucent object. A lighting processing unit that performs lighting processing of the translucent object and obtains a light reflection color of the translucent object;
An α value obtaining unit for obtaining an α value whose value changes according to the intensity of the reflected color of the obtained translucent object;
As an α blending unit that blends the color of the semi-transparent object and the destination color that is the drawing destination color of the semi-transparent object based on the obtained α value,
Make the computer work ,
The lighting processing unit
A specular color of the translucent object is obtained based on a light source vector, a line-of-sight vector of a virtual camera, and a normal vector of the translucent object, and a reflection color of the translucent object based on the obtained specular color Seeking
The α value acquisition unit
A program for obtaining an α value whose value changes in accordance with the intensity of the reflected color obtained from the specular color . A lighting processing unit that performs lighting processing of the translucent object and obtains a light reflection color of the translucent object;
An α value obtaining unit for obtaining an α value whose value changes according to the intensity of the reflected color of the obtained translucent object;
A texture mapping unit that performs environment mapping of the environment texture representing the environment around the translucent object to the translucent object;
As an α blending unit that blends the color of the semi-transparent object and the destination color that is the drawing destination color of the semi-transparent object based on the obtained α value,
Make the computer work ,
The lighting processing unit
Based on the mapping color obtained by the environment mapping, the reflection color of the translucent object is obtained,
The α value acquisition unit
A program for obtaining an α value whose value changes according to the intensity of the reflected color obtained from the mapping color of the environment mapping . In claim 4,
The lighting processing unit
The mapping color obtained in environment mapping, based on the specular color of the translucent object sought et the basis of the illumination model, obtains the reflection color of the translucent object,
The α value acquisition unit
A program for obtaining an α value whose value changes in accordance with the intensity of the reflection color obtained based on the mapping color of the environment mapping and the specular color based on the illumination model . In any of claims 3 to 5 ,
The α value acquisition unit
Obtaining an α value at which the blending rate of the color of the translucent object becomes higher as the reflection color of the translucent object becomes stronger,
The α blending part is
A program for performing an α blending process in which the blending rate of the color of the semi-transparent object with respect to the destination color increases as the reflection color of the semi-transparent object increases. In any one of Claims 3 thru | or 6 .
The α value acquisition unit
A program for obtaining an α value by an arithmetic expression of α = P1 + P2 × SP, where SP is a reflection color intensity parameter of the translucent object and P1 and P2 are material parameters. In claim 7 ,
The α value acquisition unit
A program for obtaining an α value based on the material parameters P1 and P2 set to different values depending on the material of the translucent object. A lighting processing unit that performs lighting processing of the translucent object and obtains a light reflection color of the translucent object;
An α value obtaining unit for obtaining an α value whose value changes according to the intensity of the reflected color of the obtained translucent object;
A texture mapping unit that performs environment mapping of the environment texture representing the environment around the translucent object to the translucent object;
As an α blending unit that blends the color of the semi-transparent object and the destination color that is the drawing destination color of the semi-transparent object based on the obtained α value,
Make the computer work,
A mapping color of the translucent object is set in the color channel of the environment texture, and an α value whose value changes according to the strength of the mapping color is set in the α channel of the environment texture,
The α value acquisition unit
A program for obtaining an α value whose value changes according to the intensity of reflection color of the translucent object, which is the mapping color, by the environment mapping . In any one of Claims 1 thru | or 9 ,
The α blending part is
A program characterized by blending at least a color of a semi-transparent object obtained based on a specular color, a diffuse color, and an ambient color, and a destination color based on the obtained α value. A computer-readable information storage medium, wherein the program according to any one of claims 1 to 10 is stored. An image generation system for generating an image,
A lighting processing unit that performs lighting processing of the translucent object and obtains a light reflection color of the translucent object;
An α value obtaining unit for obtaining an α value whose value changes according to the intensity of the reflected color of the obtained translucent object;
An α blending unit that blends the color of the semi-transparent object and the destination color that is the drawing destination color of the semi-transparent object based on the obtained α value;
The α value acquisition unit
An image generation system characterized in that an α value is obtained by an arithmetic expression of α = P1 + P2 × SP where SP is a reflection color intensity parameter of the translucent object and P1 and P2 are material parameters . An image generation system for generating an image,
A lighting processing unit that performs lighting processing of the translucent object and obtains a light reflection color of the translucent object;
An α value obtaining unit for obtaining an α value whose value changes according to the intensity of the reflected color of the obtained translucent object;
The color of the translucent object, said destination color and the color of drawing destination of the semi-transparent object, see contains an α blending unit for blending based on the α value determined,
The lighting processing unit
A specular color of the translucent object is obtained based on a light source vector, a virtual camera line-of-sight vector, and a normal vector of the translucent object, and based on the obtained specular color, the reflection color of the translucent object Seeking
The α value acquisition unit
An image generation system characterized in that an α value whose value changes in accordance with the intensity of a reflected color obtained from the specular color is obtained . An image generation system for generating an image,
A lighting processing unit that performs lighting processing of the translucent object and obtains a light reflection color of the translucent object;
An α value obtaining unit for obtaining an α value whose value changes according to the intensity of the reflected color of the obtained translucent object;
A texture mapping unit that performs environment mapping of the environment texture representing the environment around the translucent object to the translucent object;
The color of the translucent object, said destination color and the color of drawing destination of the semi-transparent object, see contains an α blending unit for blending based on the α value determined,
The lighting processing unit
Based on the mapping color obtained by the environment mapping, the reflection color of the translucent object is obtained,
The α value acquisition unit
An image generation system characterized in that an α value whose value changes according to the intensity of a reflected color obtained from the mapping color of the environment mapping is obtained . An image generation system for generating an image,
A lighting processing unit that performs lighting processing of the translucent object and obtains a light reflection color of the translucent object;
An α value obtaining unit for obtaining an α value whose value changes according to the intensity of the reflected color of the obtained translucent object;
A texture mapping unit that performs environment mapping of the environment texture representing the environment around the translucent object to the translucent object;
The color of the translucent object, said destination color and the color of drawing destination of the semi-transparent object, see contains an α blending unit for blending based on the α value determined,
A mapping color of the translucent object is set in the color channel of the environment texture, and an α value whose value changes according to the strength of the mapping color is set in the α channel of the environment texture,
The α value acquisition unit
An image generation system characterized in that an α value whose value changes according to the intensity of the reflected color of the translucent object, which is the mapping color, is obtained by the environment mapping .