Program, information storage medium, and image generation system

1. A computer-readable storage medium encoded with a computer program which, when executed by a computer, causes the computer to function as:

a glare source drawing section which draws a glare source while referring to a Z value of an original image stored in a Z buffer to generate a first glare source image, and draws the glare source without referring to the Z value of the original image stored in the Z buffer to generate a second glare source image;

a glare correction image generation section which performs image calculation processing including AND processing of a first image which is an image obtained by subjecting the first glare source image to first blur processing and a second image which is one of an image obtained by subjecting the second glare source image to second blur processing and the second glare source image to generate a glare correction image; and

a glare expression image generation section which generates a glare expression image in which a corrected glare effect is expressed in the original image based on the original image, the blurred image of the first glare source image, and the glare correction image.

2. The computer-readable storage medium as defined in claim 1 , wherein the glare correction image generation section performs the image calculation processing including NOT processing of the first glare source image to generate the glare correction image.

3. The computer-readable storage medium as defined in claim 2 , wherein the first blur processing and the second blur processing are different types of blur processing.

4. The computer-readable storage medium as defined in claim 3 , wherein the first blur processing is blur processing in which an amount of expansion of a blurred image with respect to a blur target image is larger than an amount of expansion of the second blur processing.

5. The computer-readable storage medium as defined in claim 3 , wherein the first blur processing includes a plurality of blur processing, in which pixel values of a blurred image obtained by the Kth (K is a natural number) blur processing are subjected to conversion processing, and the subsequent (K+1)th blur processing is performed for the blurred image subjected to the conversion processing.

6. The computer-readable storage medium as defined in claim 1 , wherein the first blur processing and the second blur processing are different types of blur processing.

7. The computer-readable storage medium as defined in claim 6 , wherein the first blur processing is blur processing in which an amount of expansion of a blurred image with respect to a blur target image is larger than an amount of expansion of the second blur processing.

8. The computer-readable storage medium as defined in claim 7 , wherein the first blur processing includes a plurality of blur processing, in which pixel values of a blurred image obtained by the Kth (K is a natural number) blur processing are subjected to conversion processing, and the subsequent (K+1)th blur processing is performed for the blurred image subjected to the conversion processing.

9. The computer-readable storage medium as defined in claim 7 , the program causing the computer to function as:

a three-dimensional information storage section which stores three-dimensional information of the glare source; and

an area size determination section which determines an area size of a blur processing area based on the three-dimensional information of the glare source,

wherein the glare correction image generation section performs the blur processing of the glare source image in the blur processing area set by the area size.

10. The computer-readable storage medium as defined in claim 9 ,

wherein the three-dimensional information storage section stores center coordinates and a radius of a spherical glare source as the three-dimensional information; and

wherein the glare source drawing section generates the glare source image by drawing a disk billboard object disposed at a position in front of the center coordinates when viewed from a virtual camera.

11. The computer-readable storage medium as defined in claim 9 ,

wherein the three-dimensional information storage section stores center coordinates, radius, and normal vector indicating surface orientation of a disk-shaped glare source as the three-dimensional information; and

wherein the glare source drawing section generates the glare source image by drawing a disk object which is disposed at the center coordinates and of which surface orientation is set by the normal vector.

12. The computer-readable storage medium as defined in claim 9 ,

wherein the three-dimensional information storage section stores a plurality of vertex coordinates of the glare source as the three-dimensional information; and

wherein the glare source drawing section generates the glare source image by drawing an object formed by vertices at the vertex coordinates.

13. The computer-readable storage medium as defined in claim 9 , wherein the area size determination section determines the size of the blur processing area by generating a bounding box which involves the glare source in a screen coordinate system based on the three-dimensional information of the glare source.

14. The computer-readable storage medium as defined in claim 6 , wherein the first blur processing includes a plurality of blur processing, in which pixel values of a blurred image obtained by the Kth (K is a natural number) blur processing are subjected to conversion processing, and the subsequent (K+1)th blur processing is performed for the blurred image subjected to the conversion processing.

15. The computer-readable storage medium as defined in claim 14 , the program causing the computer to function as:

a three-dimensional information storage section which stores three-dimensional information of the glare source; and

an area size determination section which determines an area size of a blur processing area based on the three-dimensional information of the glare source,

wherein the glare correction image generation section performs the blur processing of the glare source image in the blur processing area set by the area size.

16. The computer-readable storage medium as defined in claim 1 , the program causing the computer to function as:

a three-dimensional information storage section which stores three-dimensional information of the glare source; and

an area size determination section which determines an area size of a blur processing area based on the three-dimensional information of the glare source,

wherein the glare correction image generation section performs the blur processing of the glare source image in the blur processing area set by the area size.

17. The computer-readable storage medium as defined in claim 16 ,

wherein the three-dimensional information storage section stores center coordinates and a radius of a spherical glare source as the three-dimensional information; and

wherein the glare source drawing section generates the glare source image by drawing a disk billboard object disposed at a position in front of the center coordinates when viewed from a virtual camera.

18. The computer-readable storage medium as defined in claim 16 ,

wherein the three-dimensional information storage section stores center coordinates, radius, and normal vector indicating surface orientation of a disk-shaped glare source as the three-dimensional information; and

wherein the glare source drawing section generates the glare source image by drawing a disk object which is disposed at the center coordinates and of which surface orientation is set by the normal vector.

19. The computer-readable storage medium as defined in claim 16 ,

wherein the three-dimensional information storage section stores a plurality of vertex coordinates of the glare source as the three-dimensional information; and

wherein the glare source drawing section generates the glare source image by drawing an object formed by vertices at the vertex coordinates.

20. The computer-readable storage medium as defined in claim 16 , wherein the area size determination section determines the size of the blur processing area by generating a bounding box which involves the glare source in a screen coordinate system based on the three-dimensional information of the glare source.

21. An image generation system which generates an image, the system comprising:

a glare source drawing section which draws a glare source while referring to a Z value of an original image stored in a Z buffer to generate a first glare source image, and draws the glare source without referring to the Z value of the original image stored in the Z buffer to generate a second glare source image;

a glare correction image generation section which performs image calculation processing including AND processing of a first image which is an image obtained by subjecting the first glare source image to first blur processing and a second image which is one of an image obtained by subjecting the second glare source image to second blur processing and the second glare source image to generate a glare correction image; and

a glare expression image generation section which generates a glare expression image in which a corrected glare effect is expressed in the original image based on the original image, the blurred image of the first glare source image, and the glare correction image.