JP4462948B2 - Program, information storage medium, and image generation apparatus - Google Patents

Description

  According to the present invention, an object space projection conversion process based on a given viewpoint is performed, and color information including transparency information is determined for each pixel to generate an image of the object space reflecting the transparency information of each object. In addition, the present invention relates to a program or the like for performing a light source effect process for coloring the generated image based on color information of the light source.

As a technique for expressing a blurred portion (halation) generated around a high-luminance light source such as a solar light source, the ratio of the light source object area in the rendered image to the reference area of the light source object is calculated, and the halation is based on the calculated ratio There is known a technique for changing translucent information or color information at the time of drawing. According to this, the expression of the halation generated around the light source object can be changed depending on how the light source object is seen (see Patent Document 1).
Japanese Patent Laid-Open No. 2003-6673

  However, for example, when the light source effect by sunlight such as halation described above is drawn on an image of an object space including a semi-transparent object such as a cloud, the technique disclosed in Patent Document 1 uses the thickness of the cloud. It was not possible to change the expression of the light source effect according to (transparency). Therefore, an object of the present invention is to provide a program or the like for expressing a light source effect corresponding to the transparency of an object space image including a translucent object.

According to a first aspect of the present invention for solving the above problems, the transparency of each object is determined by causing a computer to perform projection conversion processing of an object space based on a given viewpoint and determining color information including transparency information for each pixel. A program for generating an image of the object space reflecting information and performing a light source effect process for coloring the generated image based on color information of a light source,
Area setting means (for example, a light source effect drawing unit 232 shown in FIG. 2) for setting an irradiation source determination area in the generated image based on the position of the light source;
A coloring information setting means (for example, a light source effect drawing unit 232 shown in FIG. 2) for setting color information at the time of coloring in the light source effect processing based on transparency information of the irradiation source determination region;
As a program for causing the computer to function.

Further, the tenth invention performs projection conversion processing of the object space based on a given viewpoint, and determines color information including transparency information for each pixel, thereby reflecting the transparency information of each object. An image generation apparatus for performing light source effect processing for generating an image and coloring the generated image based on color information of a light source,
Area setting means for setting an irradiation source determination area in the generated image based on the position of the light source;
Coloring information setting means for setting color information at the time of coloring in the light source effect processing based on transparency information of the irradiation source determination region;
It is characterized by having.

  According to the first or tenth aspect of the present invention, when performing the light source effect processing for coloring based on the color information of the light source, the light source effect is based on the transparency information of the irradiation source determination area set based on the position of the light source. Color information at the time of coloring in the process can be set.

The second invention is the program of the first invention,
The area setting unit is configured to cause the computer to function so as to set, as the irradiation source determination area, a range including the entire light source in the generated image when the light source is subjected to projection conversion processing without performing hidden surface removal processing. It is a program.

  According to the second aspect of the invention, the range including the entire light source in the generated image when the light source is subjected to the projection conversion process without performing the hidden surface removal process is set as the irradiation source determination area, and based on the irradiation source determination area Color information at the time of coloring in the light source effect process can be set.

The third invention is the program of the first or second invention,
The coloring information setting unit includes a determination unit that determines a portion of the irradiation source determination region other than a portion where an object that does not satisfy a predetermined transparency condition is drawn as a determination portion, and is determined by the determination unit. A program for causing the computer to function so as to set color information at the time of coloring based on transparency information of the determined portion.

  According to the third aspect of the present invention, the irradiation source determination region is determined as a determination portion other than the portion where the object that does not satisfy the predetermined transparency condition is drawn, and based on the transparency information of the determination portion, Color information at the time of coloring in the light source effect process can be set.

In a fourth aspect of the invention, the computer is caused to draw an object that does not satisfy the transparency condition by a Z buffer method for drawing by referring to and updating a depth value (Z value) viewed from the viewpoint, and an object that satisfies the transparency condition is drawn. The program according to claim 3, wherein the image of the object space is generated by drawing with the Z buffer method while performing the reference without updating the Z value.
The determination means determines a portion of the irradiation source determination region where an object that does not satisfy the transparency condition is drawn based on the Z value, and sets a portion other than the determined portion as a determination portion. Is a program for causing the computer to function.

  According to the fourth invention, a portion other than a portion in which an object that does not satisfy the transparency condition in the irradiation source determination region determined based on the Z value is drawn is determined as a determination portion, and the determination portion Based on the transparency information, color information at the time of coloring in the light source effect process can be set.

The fifth invention is the program of the third or fourth invention,
The coloring information setting means functions the computer to set color information at the time of coloring based on a value obtained by averaging the transparency information of the determination portion determined by the determination means with the size of the irradiation source determination area. It is a program to make it.

  According to the fifth aspect, it is possible to set color information during coloring in the light source effect processing based on a value obtained by averaging the transparency information of the determination portion described above with the size of the irradiation source determination region.

A sixth invention is a program according to any one of the third to fifth inventions,
The transparency condition is translucent.

  According to the sixth aspect of the invention, it is possible to set color information during coloring in the light source effect processing based on the transparency information of the portion where the semi-transparent object is drawn in the irradiation source determination region.

A seventh invention is a program according to any one of the third to fifth inventions,
The transparency condition is a program which is a value on a transparent side when transparency is divided into a value on an opaque side and a value on a transparent side.

  According to the seventh aspect of the present invention, based on the transparency information of the portion in which the transparency value is set as the transparency information in the irradiation source determination area when the transparency is divided into the opaque value and the transparent value. Thus, color information at the time of coloring in the light source effect process can be set.

The eighth invention is a program of the first to seventh inventions,
The coloring information setting means causes the computer to function to set transparency information among color information at the time of coloring in the light source effect processing.
It is a program for causing the computer to function as means for coloring the generated image and performing the light source effect processing by translucent synthesis processing based on transparency information set by the coloring information setting means.

  According to the eighth aspect, the transparency information at the time of coloring in the light source effect process is set based on the transparency information of the irradiation source determination region in the generated image, and is generated by the translucent synthesis process based on the set transparency information. It is possible to perform light source effect processing by coloring an image.

  A ninth invention is a computer-readable information storage medium storing the program of any one of the first to eighth inventions.

  According to the ninth aspect of the invention, an information storage medium that achieves the same effects as any of the first to eighth aspects of the invention is realized by causing a computer to read out a program from the information storage medium and perform arithmetic processing. be able to.

  According to the present invention, when performing light source effect processing for coloring based on color information of the light source, the color at the time of coloring in the light source effect processing is based on the transparency information of the irradiation source determination area set based on the position of the light source. Information can be set.

  Hereinafter, an image generation apparatus to which the present invention is applied will be described in detail with reference to the drawings.

[First Embodiment]
First, for the first embodiment, a light source effect by sunlight of the sun (light source) arranged at infinity in the image of the object space is drawn on the image after projection conversion (original image) drawn in the frame buffer ( A case where light source effect processing is performed) will be described as an example. When the original image is drawn in the frame buffer, drawing is performed from an opaque object (opaque object), and finally a semitransparent object (semitransparent object) is drawn. In the first embodiment, when the image generation apparatus draws a translucent object, the α value (transparency information; 0 ≦ α ≦ 1.0, α = 0 is transparent, α = 1.0 means opaqueness), and drawing is performed when the value is smaller than the α value of the pixel to be drawn.

[principle]
First, the principle of the first embodiment will be described with reference to FIG. FIG. 1A shows an original image drawn in the frame buffer. A cloud object O10, which is a semi-transparent object, is drawn in the frame buffer. The irradiation source determination area E10 is determined based on the position and size of the light source (sun) in the original image. Specifically, a range including the entire light source in the original image when the light source is subjected to projection conversion processing without performing hidden surface erasure processing is determined as the irradiation source determination region. In FIG. 1A, the position and size of the light source are indicated by dotted lines.

  Then, based on the α value of the irradiation source determination area E10 determined as described above, the α value of the color palette (LUT) referred to for color designation when rendering the light source effect is determined. That is, as shown in FIG. 1B, first, the α value of the irradiation source determination area E10 stored in the frame buffer is extracted and sampled, and enlarged or reduced to a size of 16 dots × 16 dots. Subsequently, the α value set for each dot in the irradiation source determination area E10 is reversed by subtracting from 1.

  Next, processing for averaging information (values) of adjacent dots is performed, and the irradiation source determination region E10 is finally reduced to one dot, so that the inverted value in the irradiation source determination region E10 is obtained. Find the average. Then, the obtained value is enlarged to a size of 16 dots × 16 dots and set as an α value of a color palette (LUT) for light source effect drawing. Here, the process of reducing or enlarging the irradiation source determination area to 1 dot is performed by reducing or enlarging the image. That is, since a circuit for performing image reduction / enlargement processing is normally incorporated in an image generation apparatus (for example, as a DSP), an average value can be calculated at a high speed (to one dot) by using this circuit. Image reduction) and development (image enlargement from one dot).

  In this way, by inverting the α value of the irradiation source determination area E10, it is possible to determine that the dot portion with the inverted value = 0 is the portion where the opaque object is drawn. That is, it can be determined that the sun arranged at infinity is hidden in the inverted dot portion of the value = 0. Therefore, the value of the dot portion whose inverted value is other than 0 (that is, the portion where the opaque object is not drawn (an example of the determination portion in the claims)) is the size of the irradiation source determination region E10 ( The α value of the color palette (LUT) for light source effect drawing is set with a value averaged by the number of dots). That is, the degree of incident light (color information for light source effect drawing) is varied depending on the transparency of the portion that does not block sunlight.

[Function configuration]
Next, a functional configuration of the image generation apparatus 10 in the first embodiment will be described. FIG. 2 is a block diagram illustrating an example of a functional configuration of the image generation apparatus 10. As illustrated in FIG. 2, the image generation apparatus 10 includes an input unit 100, a processing unit 200, a display unit 300, a storage unit 400, and a temporary storage unit 500.

  The input unit 100 is for inputting various operations, and an operation signal input from the input unit 100 is output to the processing unit 200.

  The processing unit 200 performs various processes such as control of the entire image generation apparatus 10, instructions to each function unit in the image generation apparatus 10, and image processing based on programs and data stored in the storage unit 400. The function of the processing unit 200 is realized by hardware such as various processors (CPU, DSP, etc.), ASIC (gate array, etc.), and a given program.

  The processing unit 200 includes an object space setting unit 210, a viewpoint setting unit 220, and an image generation unit 230 as main functional units, and generates one image in one frame time (1/60 seconds). Display on the display unit 300. Therefore, high speed is required for image generation.

  The object space setting unit 210 performs processing for arranging an object such as a light source or a cloud object in the object space, and outputs the processing result to the image generation unit 230.

  The viewpoint setting unit 220 performs processing for determining the viewpoint and line-of-sight direction of the virtual camera that can move in the horizontal direction and the vertical direction in the object space, and outputs the processing result to the image generation unit 230.

  The image generation unit 230 generates an image based on the calculation results of the object space setting unit 210 and the viewpoint setting unit 220 according to the image generation program 402, and outputs an image signal of the generated image to the display unit 300. The image generation unit 230 includes a light source effect drawing unit 232 that executes processing related to light source effect drawing.

  The light source effect drawing unit 232 is a functional unit that executes the first light source effect drawing process according to the first light source effect drawing program 402a, and is based on the position and size of the light source (sun) in the original image drawn in the frame buffer 502. Then, an irradiation source determination region is determined, and processing for determining the α value of the color palette (LUT) 504 for light source effect drawing is performed based on the α value of the irradiation source determination region.

  The display unit 300 displays various screens based on the image signal input from the image generation unit 230.

  The storage unit 400 stores various programs and data. In particular, in order to implement the first embodiment, an image generation program 402 having a first light source effect drawing program 402a is stored.

  The temporary storage unit 500 temporarily stores various programs executed by the processing unit 200, data related to the execution of these programs, image data generated by the image generation unit 230, and the like. In order to implement the first embodiment, the temporary storage unit 500 is particularly referred to for a frame buffer 502 in which an image generated by the image generation unit 230 is stored, and for color designation when rendering a light source effect. Color palette (LUT) 504. The function of the temporary storage unit 500 can be realized by a RAM, a VRAM, or the like.

[Process flow]
Next, the flow of processing of the light source effect drawing unit 232 in the first embodiment will be described with reference to FIG. FIG. 3 is a flowchart illustrating an example of the operation of the light source effect drawing unit 232 according to the execution of the first light source effect drawing process. This first light source effect drawing process is realized by the light source effect drawing unit 232 reading out and executing the first light source effect drawing program 402a, and the object space setting unit 210 performs the object light source, cloud object, and other objects. Arrangement processing is performed, the viewpoint setting unit 220 determines the viewpoint and line-of-sight direction of the virtual camera, and the image generation unit 230 projects and converts the object space image viewed from the virtual camera into the viewpoint coordinate system and stores it in the frame buffer 502. Executed after drawing.

  As shown in FIG. 3, the light source effect drawing unit 232 first calculates the position and size in the viewpoint coordinate system by projecting and transforming the light source (sun) (step a10), and calculates the position and size of the calculated light source. Based on this, an irradiation source determination area is determined (step a20).

  Next, the light source effect drawing unit 232 extracts and samples the α value of the irradiation source determination area stored in the frame buffer 502 to enlarge or reduce the size to 16 dots × 16 dots (step a30). The value set for the dot is reversed (step a40). Specifically, a value obtained by subtracting the α value from 1 is used. Subsequently, the light source effect drawing unit 232 performs a process of averaging information of adjacent dots to reduce the irradiation source determination area to 1 dot (step a50), and the obtained value is a size of 16 dots × 16 dots. The image is enlarged (step a60) and set as the α value of the color palette (LUT) 504 (step a70). Then, the light source effect drawing unit 232 colors the original image by the semi-transparent synthesis process based on the α value set in the color palette (LUT) 504, and draws the light source effect (step a80).

  4 and 5 are diagrams illustrating an example of an image generated by the first light source effect drawing process. 4 and 5 show an example of an image in which the light source effect by sunlight is drawn on the original image on which the clouds are drawn. FIG. 5 shows a cloud thicker than the clouds drawn in FIG. That is, an image in which a light source effect by sunlight is drawn on an image in which a value larger than the α value set in the cloud shown in FIG. 4 (a cloud in which a more opaque value is set as transparency) is drawn. An example is shown. As shown in FIGS. 4 and 5, by executing the first light source effect drawing process, the light source effect is drawn with the brightness according to the thickness of the cloud.

[Hardware configuration]
Next, an example of a hardware configuration for realizing the image generation device 10 according to the first embodiment will be described with reference to FIG. In the apparatus shown in FIG. 6, a CPU 1000, a ROM 1002, a RAM 1004, a VRAM 1005, an information storage medium 1006, an image generation IC 1010, a sound generation IC 1008, and I / O ports 1012 and 1014 are connected to each other via a system bus 1016. Yes. A control device 1022 is connected to the I / O port 1012, and a communication device 1024 is connected to the I / O port 1014.

  The CPU 1000 controls the entire apparatus and performs various data processing in accordance with a program stored in the information storage medium 1006, a system program stored in the ROM 1002 (such as initialization information of the apparatus main body), and a signal input by the control apparatus 1022. Do.

The RAM 1004 is a storage unit used as a work area of the CPU 1000, and stores given contents in the information storage medium 1006 and the ROM 1002, the calculation result of the CPU 1000, and the like.
The VRAM 1005 is a storage device that temporarily stores image data to be displayed on the display device 1018, and is a frame buffer (frame shown in FIG. 2) for storing image data for one frame generated by the image generation IC 1010. Equivalent to the buffer 502).
The RAM 1004 and the VRAM 1005 correspond to the temporary storage unit 500 shown in FIG.

  An information storage medium 1006 mainly stores programs, image data, sound data, play data, and the like. As an information storage medium, a memory such as a ROM, a hard disk, a CD-ROM, a DVD, an IC card, a magnetic A disk, an optical disk or the like is used. The information storage medium 1006 corresponds to the storage unit 400 shown in FIG.

  In addition, the image generation IC 1010 and the sound generation IC 1008 provided in this apparatus can appropriately output sound and images.

  The image generation IC 1010 is an integrated circuit that generates pixel information based on information sent from the ROM 1002, the RAM 1004, the information storage medium 1006, and the like according to instructions from the CPU 1000, and the generated display signal is output to the display device 1018. . The display device 1018 is realized by a CRT, LCD, TV, plasma display, projector, or the like, and corresponds to the display unit 300 illustrated in FIG.

  The sound generation IC 1008 is an integrated circuit that generates sound signals according to information stored in the information storage medium 1006 and the ROM 1002 and sound data stored in the RAM 1004 according to instructions from the CPU 1000. Output from the speaker 1020.

  The control device 1022 is a device for the player to input an operation related to the game, and its function is realized by hardware such as a lever, a button, and a housing. The control device 1022 corresponds to the input unit 100 shown in FIG.

  The communication device 1024 exchanges information used inside the device with the outside. The communication device 1024 is connected to other devices via a communication line, and is used to send and receive given information according to a program.

  The above-described processing such as the first light source effect drawing processing includes the information storage medium 1006 that stores the first light source effect program 402a and the like shown in FIG. 2, the CPU 1000 that operates according to these programs, the image generation IC 1010, the sound generation IC 1008, and the like. It is realized by. The CPU 1000 and the image generation IC 1010 correspond to the processing unit 200 shown in FIG. 2, and the CPU 1000 mainly uses the object space setting unit 210 and the viewpoint setting unit 220 shown in FIG. 2, and the image generation IC 1010 shows the image shown in FIG. This corresponds to the generation unit 230.

  Note that the processing performed by the image generation IC 1010, the sound generation IC 1008, and the like may be performed by software using the CPU 1000 or a general-purpose DSP. In this case, the CPU 1000 corresponds to the processing unit 200 shown in FIG.

  As described above, according to the first embodiment, an opaque object is drawn in the irradiation source determination region by extracting and inverting the α value of the irradiation source determination region determined based on the position and size of the light source. It is possible to determine a portion that has not been rendered, and to set the α value of the color palette (LUT) 504 for light source effect rendering based on the transparency information of the portion where the opaque object has not been rendered. Then, the light source effect can be drawn by coloring the original image by the translucent composition processing based on the α value set in the color palette (LUT) 504.

[Second Embodiment]
Next, as in the first embodiment, the second embodiment will be described by taking as an example a case where a light source effect by sunlight is drawn on an original image after projection conversion drawn in a frame buffer.

  In the second embodiment, the image generation apparatus of the present invention cannot be drawn while comparing the α value of the pixel to be drawn with the α value stored in the frame buffer as in the image generation apparatus 10 of the first embodiment (that is, In this embodiment, the present invention is applied to an apparatus that always draws a translucent object by overwriting. In the second embodiment, the image generation apparatus draws a translucent object when, for example, the α value of the pixel to be drawn is 0.5 or more (drawn by overwriting). In the following, the same components as those in the first embodiment, such as the functional configuration and the hardware configuration, are denoted by the same reference numerals and description thereof is omitted.

[principle]
First, the principle of the second embodiment will be described with reference to FIG. FIG. 7A shows an original image drawn in the frame buffer. A cloud object O20, which is a semi-transparent object, is drawn in the frame buffer. As in the first embodiment, the irradiation source determination region E20 is determined based on the position and size of the light source (sun) in this original image. In FIG. 7A, the position and size of the light source are indicated by dotted lines.

  Then, the α value of the color palette (LUT) for light source effect drawing is determined based on the α value of the irradiation source determination region E20 determined as described above. That is, as shown in FIG. 7B, first, the α value of the irradiation source determination area E20 stored in the frame buffer is extracted and sampled, and enlarged or reduced to a size of 16 dots × 16 dots. Here, in FIG. 7B, the α value is set to “0” for the upper left dot and the right adjacent dot. This is because the α value is less than 0.5. This indicates that the dot portion of O20 has not been drawn.

  Next, the value set for each dot at this stage is doubled and then inverted. At this time, if the inversion result becomes a negative value, that is, if the inversion result becomes negative due to the calculation of 1.0-2 × α, the value is corrected to “0”.

  Subsequently, processing for averaging information (values) of adjacent dots is performed, and the irradiation source determination region E20 is finally reduced to one dot, so that the inverted value in the irradiation source determination region E20 is obtained. Find the average. Then, the obtained value is enlarged to a size of 16 dots × 16 dots and set as an α value of a color palette (LUT) for light source effect drawing.

  In this way, by doubling and inverting the α value of the irradiation source determination area E20, the inverted dot portion of the value = 0 is changed to a portion where a translucent object having an α value of 0.5 or more is drawn. Can be determined. Therefore, the value of a dot portion whose inverted value is other than 0 (that is, a portion where a translucent object having an α value of 0.5 or more is not drawn (an example of a determination portion in the claims)) is used. The α value of the color palette (LUT) for rendering the light source effect is set by a value averaged by the size (number of dots) of the irradiation source determination area E20.

[Configuration of storage unit]
FIG. 8 is a diagram illustrating a configuration example of the storage unit 420 according to the second embodiment. The image generation apparatus according to the second embodiment is an apparatus having the same configuration as the configuration of the image generation apparatus 10 shown in FIG. 2 in the first embodiment except that the storage unit 400 is replaced with the storage unit 420 shown in FIG. Realized.

  As shown in FIG. 8, the storage unit 420 stores an image generation program 422 having a second light source effect drawing program 422a, in particular, for realizing the second embodiment. The light source effect drawing unit 232 executes the second light source effect drawing process according to the second light source effect drawing program 422a, and based on the position and size of the light source (sun) in the original image drawn in the frame buffer 502 A determination area is determined, and processing for determining the α value of the color palette (LUT) 504 for light source effect drawing is performed based on the α value of the irradiation source determination area.

[Process flow]
Next, a processing flow of the light source effect rendering unit 232 in the second embodiment will be described with reference to FIG. FIG. 9 is a flowchart illustrating an example of the operation of the light source effect drawing unit 232 according to the execution of the second light source effect drawing process. The second light source effect drawing process is realized by the light source effect drawing unit 232 reading out and executing the second light source effect drawing program 422a, and the object space setting unit 210 performs the same as in the first embodiment. Arrangement processing of objects such as light sources and cloud objects is performed, the viewpoint setting unit 220 determines the viewpoint and line-of-sight direction of the virtual camera, and the image generation unit 230 converts the object space image viewed from the virtual camera into the viewpoint coordinate system. This is executed after the projection conversion and drawing in the frame buffer 502.

  As shown in FIG. 9, the light source effect drawing unit 232 first calculates the position and size in the viewpoint coordinate system by projecting the light source (sun) (step b10), and calculates the position and size of the calculated light source. The irradiation source determination area according to the above is determined (step b20).

  Next, the light source effect drawing unit 232 extracts and samples the α value of the irradiation source determination area stored in the frame buffer 502 and enlarges or reduces it to a size of 16 dots × 16 dots (step b30). Next, the light source effect drawing unit 232 doubles the value set for each dot (step b40) and then inverts (step b50). Specifically, the light source effect rendering unit 232 inverts the value set for each dot by subtracting from 1, and corrects the value to “0” when the inversion result is a negative value. To do.

  Subsequently, the light source effect drawing unit 232 performs processing for averaging information of adjacent dots to reduce the irradiation source determination area to 1 dot (step b60), and sets the obtained value to a size of 16 dots × 16 dots. The image is enlarged (step b70) and set as the α value of the color palette (LUT) 504 (step b80). Then, the light source effect drawing unit 232 colors the original image by the translucent synthesis process based on the α value set in the color palette (LUT) 504, and draws the light source effect (step b90).

  As described above, according to the second embodiment, in the image generation apparatus that cannot draw while comparing the α value of the pixel to be drawn with the α value stored in the frame buffer, the α of the pixel to be drawn For example, when the value is 0.5 or more, drawing is performed, and after extracting the α value of the irradiation source determination region, it is doubled and inverted so that the α value is 0.5 or more in the irradiation source determination region. A portion where a transparent object is not drawn can be determined. Then, the α value of the color palette (LUT) 504 for light source effect drawing is set based on the α value of the portion where the semi-transparent object having the α value of 0.5 or more is not drawn, and this color palette (LUT ) It is possible to render the light source effect by coloring the original image by the translucent composition processing based on the α value set to 504.

[Third Embodiment]
Next, as in the first embodiment, the third embodiment will be described by taking as an example a case where a light source effect by sunlight is drawn on an original image after projection conversion drawn in a frame buffer. In the following, the same components as those in the first embodiment, such as the functional configuration and the hardware configuration, are denoted by the same reference numerals and description thereof is omitted.

  The image generating apparatus according to the third embodiment draws an opaque object by referring to and updating the depth value (Z value) using the Z buffer method, and does not update the Z value for the translucent object. This is a device for drawing while referring to it. Therefore, it has a Z buffer that stores the depth value (Z value) of the generated image for each pixel. However, only the depth value (Z value) of the opaque object is stored in this Z buffer, and the depth value (Z value) of the translucent object is not stored. The image generation apparatus according to the third embodiment refers to the α value stored in the frame buffer when rendering a translucent object. If the value is smaller than the α value of the pixel to be rendered, the RGB value and When the α value is written and larger than the α value of the pixel to be drawn, the device writes and draws only the RGB value without writing the α value.

[principle]
First, the principle of the third embodiment will be described with reference to FIGS. FIG. 10 is a diagram illustrating an example of an original image drawn in the frame buffer. In the frame buffer, a building object O32 that is an opaque object and a cloud object O30 that is a translucent object are drawn.

  The image generation apparatus according to the third embodiment generates a filter image according to the depth value of the irradiation source determination region E30 determined based on the position and size of the light source (sun) in the original image drawn in the frame buffer ( Z test processing) is executed, and the light source effect is drawn in consideration of the Z test processing result. In FIG. 10, the position and size of the light source are indicated by dotted lines.

  Here, the principle of the Z test process will be described with reference to FIG. First, the depth value corresponding to the irradiation source determination region E30 shown in FIG. 10 is extracted from the Z buffer, sampled, and enlarged or reduced to a size of 16 dots × 16 dots. Further, a Z test light source image having a size of 16 dots × 16 dots, each of which is set to “0” as the RGB value, is generated, and the depth value of the light source (for example, “0.01” representing infinity) is generated as the depth value. ) Is set. Then, the depth value of the irradiation source determination region E30 extracted and sampled as described above is compared with the depth value of the generated Z test light source image, and the depth value of the irradiation source determination region E30 is determined as the Z test light source image. When the depth value is equal to or less than the depth value, a filter image in which “1” is set is generated. That is, a filter image in which “0” is set to the dot value of a portion where an opaque object positioned in front of the light source is drawn with respect to the viewpoint is generated.

  In the third embodiment, the α value of the color palette (LUT) for light source effect drawing is based on the α value of the irradiation reduction determination area E30 shown in FIG. 10 determined as described above and the generated filter image. Is determined. FIG. 12 is a diagram for explaining the principle of the third embodiment. As shown in FIG. 12, first, the α value of the irradiation source determination area stored in the frame buffer is extracted and sampled to be enlarged or reduced to a size of 16 dots × 16 dots. Subsequently, the α value set for each dot in the irradiation source determination region E30 is inverted by subtracting from 1, and is multiplied by the value set for each dot of the filter image.

  Next, processing for averaging information (values) of adjacent dots is performed, and the irradiation source determination area E30 is finally reduced to one dot, so that the inverted value in the irradiation source determination area E30 is obtained. Find the average. Then, the obtained value is enlarged to a size of 16 dots × 16 dots and set as an α value of a color palette (LUT) for light source effect drawing.

  As described above, in the third embodiment, the α value of the irradiation source determination region E30 is inverted and multiplied by the value set for each dot of the filter image, so that the dot portion of the obtained value = 0 is opaque. By determining that the object is drawn, it can be determined that the sun placed at infinity is hidden in the obtained dot portion of value = 0. Therefore, the value of the dot portion whose inverted value is other than 0 (that is, the portion where the opaque object is not drawn (an example of the determination portion in the claims)) is the size of the irradiation source determination region E30 ( The α value of the color palette (LUT) for light source effect drawing is set with a value averaged by the number of dots). That is, the degree of incident light (color information for light source effect drawing) is varied depending on the transparency of the portion that does not block sunlight.

[Configuration of storage unit / temporary storage unit]
FIG. 13 is a diagram illustrating a configuration example of the storage unit 440 and the temporary storage unit 540 according to the third embodiment. In the image generation apparatus according to the third embodiment, in the configuration of the image generation apparatus 10 illustrated in FIG. 2 in the first embodiment, the storage unit 400 is replaced with the storage unit 440 illustrated in FIG. The temporary storage unit 540 shown in FIG. 13B is realized by an apparatus having the same configuration as the replaced configuration.

  As shown in FIG. 13A, the storage unit 440 stores an image generation program 422 having a third light source effect drawing program 442a, in particular, for realizing the third embodiment. The light source effect drawing unit 232 executes the third light source effect drawing process according to the third light source effect drawing program 442a, and based on the position and size of the light source (sun) in the original image drawn in the frame buffer 541 Determine the judgment area. Then, the light source effect drawing unit 232 refers to the Z buffer 542, generates a filter image 545 based on the depth value of the irradiation source determination region, and based on the α value of the irradiation source determination region and the filter image 545, Processing for determining the α value of the color palette (LUT) 543 for light source effect drawing is performed.

  Further, as illustrated in FIG. 13B, the temporary storage unit 540 realizes the third embodiment, in particular, a frame buffer 541 in which an image generated by the image generation unit 230 is stored, and a frame buffer 541. Based on the depth value of the light source, the Z buffer 542 that stores the depth value for each pixel of the image, the color palette (LUT) 543 that is referred to for color designation when rendering the light source effect, and the like. A Z test light source image 544 to be generated, and a filter image 545 generated based on the depth value of the irradiation source determination region and the Z test light source image 544 are included.

[Process flow]
Next, a processing flow of the light source effect drawing unit 232 in the third embodiment will be described with reference to FIG. FIG. 14 is a flowchart illustrating an example of the operation of the light source effect drawing unit 232 according to the execution of the third light source effect drawing process. The third light source effect drawing process is realized by the light source effect drawing unit 232 reading and executing the third light source effect drawing program 442a. The object space setting unit 210 performs the light source, cloud object, building object, and the like. The viewpoint setting unit 220 determines the viewpoint and line-of-sight direction of the virtual camera, and the image generation unit 230 projects the object space image viewed from the virtual camera onto the viewpoint coordinate system to generate a frame. It is executed after drawing in the buffer 541.

  As shown in FIG. 14, the light source effect drawing unit 232 first calculates the position and size in the viewpoint coordinate system by projecting and transforming the light source (sun) (step c10), and calculates the position and size of the calculated light source. Based on this, an irradiation source determination area is determined (step c20). Subsequently, the light source effect drawing unit 232 executes Z test processing (step c30).

  FIG. 15 is a flowchart illustrating an example of the operation of the light source effect drawing unit 232 related to the execution of the Z test process. As shown in FIG. 15, the light source effect drawing unit 232 first extracts and samples the depth value of the irradiation source determination area stored in the Z buffer 542 and enlarges or reduces it to a size of 16 dots × 16 dots. (Step d10). Subsequently, the light source effect drawing unit 232 generates a Z test light source image having a size of 16 dots × 16 dots in which the depth value of the light source is set as the depth value, and the depth value of each dot is extracted and extracted in step d10. A filter image 545 in which “1.0” is set is generated when the depth value is not more than the sampled irradiation source determination region (step d20).

  Returning to FIG. 14, the light source effect drawing unit 232 subsequently extracts and samples the α value of the irradiation source determination area stored in the frame buffer 541 and expands or reduces the size to 16 dots × 16 dots ( Step c40), the α value set for each dot is inverted (step c50). Specifically, a value obtained by subtracting the α value from 1 is used.

  Subsequently, the light source effect drawing unit 232 performs filter processing, and multiplies the value set for each dot at this stage by the value set for each dot of the filter image 545 (step c60).

  Then, the light source effect drawing unit 232 performs a process of averaging information of adjacent dots to reduce the irradiation source determination region to 1 dot (step c70), and the obtained value is a size of 16 dots × 16 dots. (Step c80) and set as the α value of the color palette (LUT) 543 (step c90). Then, the light source effect drawing unit 232 colors the original image by the translucent synthesis process based on the α value set in the color palette (LUT) 543, and draws the light source effect (step c100).

  16 to 19 are diagrams illustrating examples of images generated by the third light source effect drawing process. 16 and 17 show an example of an image in which a light source effect by sunlight is drawn on an original image on which clouds and buildings are drawn. FIG. 17 is thinner than the clouds drawn in FIG. A light source effect by sunlight is applied to a cloud (that is, a cloud in which a value (a transparent value) smaller than the α value set in the cloud shown in FIG. 16 is set as transparency) and an image in which a building is drawn. An example of a drawn image is shown. 18 and 19 show an example of images with different viewpoint positions, and FIG. 19 shows an example of an image when the viewpoint position in FIG. 18 is moved to the right in FIG. ing. As shown in FIGS. 16 to 19, by executing the third light source effect drawing process, when a part of the light source is hidden in the opaque object, the light source effect is drawn with brightness in consideration of the degree. The

  As described above, according to the third embodiment, the depth value of the light source and the position of the viewpoint are obtained by inverting the α value of the irradiation source determination region and multiplying it by the value set for each dot of the filter image. And determine the part other than the part where the opaque object is drawn, and based on the alpha value of the part where the opaque object is not drawn, the alpha value of the color palette (LUT) 543 for light source effect drawing is determined. Can be set. Then, the light source effect can be drawn by coloring the original image by the translucent composition processing based on the α value set in the color palette (LUT) 543.

  In the third embodiment, the light source is the sun arranged at infinity, but it is needless to say that the present invention is applicable to light sources arranged at other positions. In the third embodiment, the Z test process is added based on the first embodiment. However, the Z test process may be added to the second embodiment to obtain a similar form. is there.

  The three embodiments of the image generation apparatus to which the present invention is applied have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention. For example, in each of the embodiments described above, the α value of the color palette (LUT) for light source effect drawing is set based on the α value of the portion where the opaque object is not drawn in the irradiation source determination region. The RGB values of the color palette (LUT) may be set respectively. Specifically, the light source effect drawing unit 232 inverts the α value set in the irradiation source determination area and averages the value obtained by reducing it to 1 dot in a color palette (LUT). The RGB value of the color palette (LUT) may be newly set by adding and synthesizing the preset RGB value.

  Further, in each of the above-described embodiments, the value of the irradiation source determination region is averaged by reducing the image of the irradiation source determination region to 1 dot. Good. In addition, although the size of the irradiation source determination region is 16 × 16 dots, the size is not limited to this size, and the irradiation source determination region may have any size. Further, although the light source is the sun, it goes without saying that other light sources may be used.

The figure for demonstrating the principle of 1st Embodiment. FIG. 2 is a block diagram illustrating an example of a functional configuration of the image generation apparatus according to the first embodiment. The flowchart which shows an example of a 1st light source effect drawing process. The figure which shows an example of the image produced | generated by the 1st light source effect drawing process. The figure which shows an example of the image produced | generated by the 1st light source effect drawing process. The figure which shows an example of the hardware constitutions of an image generation apparatus. The figure for demonstrating the principle of 2nd Embodiment. The figure which shows an example of a structure of the memory | storage part of the image generation apparatus in 2nd Embodiment. The flowchart which shows an example of a 2nd light source effect drawing process. The figure which shows an example of an original image. The figure for demonstrating the principle of Z test process. The figure for demonstrating the principle of 3rd Embodiment. The figure which shows an example of the structure (a) of the memory | storage part of the image generation apparatus in 3rd Embodiment, and the structure (b) of a temporary memory part. The flowchart which shows an example of a 3rd light source effect drawing process. The flowchart which shows an example of Z test process. The figure which shows an example of the image produced | generated by the 3rd light source effect drawing process. The figure which shows an example of the image produced | generated by the 3rd light source effect drawing process. The figure which shows an example of the image produced | generated by the 3rd light source effect drawing process. The figure which shows an example of the image produced | generated by the 3rd light source effect drawing process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image generation apparatus 100 Input part 200 Processing part 210 Object space setting part 220 Viewpoint setting part 230 Image generation part 232 Light source effect drawing part 300 Display part 400 Storage part 402 Image generation program 402a Light source effect drawing program 500 Temporary storage part 502 Frame buffer 504 Color Palette (LUT)

Claims (5)

By calculating the color information including the transparency of each dot constituting the image on the computer, the image of the object space (hereinafter referred to as the “original image”) including the object with the light source and transparency set from a given viewpoint is set. A program for generating and further drawing a light source effect for coloring on the original image based on the color information of the light source,
In the original image, an area setting means for setting an irradiation source determination area including a drawing area when only the light source is drawn without performing hidden surface erasure processing,
Transparency determining means for determining transparency when drawing the light source effect using the transparency of each dot in the irradiation source determination region in the original image,
A light source effect processing means for translucently combining the light source effect with the determined transparency on the original image;
A program for causing the computer to function as   The transparency determining means is
  Determination means for determining a portion of the irradiation source determination region where the opaque object is not drawn using the transparency of each dot of the irradiation source determination region;
  Averaging means for averaging the transparency of each dot of the part determined by the determination means by the number of dots of the entire irradiation source determination area;
  And determining the averaged transparency as transparency when rendering the light source effect.
  The program according to claim 1 for causing the computer to function.   2. The program according to claim 1, wherein the computer refers to a depth value (Z value) of each dot constituting an image and causes the original image to be generated by a Z buffer method for updating the Z value for an opaque object. Because
  The transparency determining means is
  Determination means for determining a portion of the irradiation source determination region where an opaque object is not drawn, using the Z value of each dot in the irradiation source determination region;
  Averaging means for averaging the transparency of each dot of the part determined by the determination means by the number of dots of the entire irradiation source determination area;
  And determining the averaged transparency as transparency when rendering the light source effect.
  Program for causing the computer to function. The computer-readable information storage medium which memorize | stored the program as described in any one of Claims 1-3 . By calculating color information including the transparency of each dot constituting the image, an image of the object space (hereinafter referred to as “original image”) including the light source viewed from a given viewpoint and the object with the transparency set is generated. On the original image, an image generation device that further draws a light source effect for coloring based on color information of the light source,
In the original image, an area setting means for setting an irradiation source determination area including a drawing area when only the light source is drawn without performing hidden surface erasure processing;
Transparency determining means for determining the transparency when drawing the light source effect, using the transparency of each dot of the irradiation source determination area in the original image,
A light source effect processing means for translucently combining the light source effect with the determined transparency on the original image;
An image generation apparatus comprising: