Game system and image creating method

• US 20020155888A1
• Filed: 10/15/2001
• Published: 10/24/2002
• Est. Priority Date: 01/28/2000
• Status: Active Grant

• Current Assignee: Bandai Namco Entertainment Inc. (BANDAI NAMCO Holdings Inc.)
• Original Assignee: Namco Bandai Games Inc. (BANDAI NAMCO Holdings Inc.)
• Inventors: Kitsutaka, Shigeru
• Granted Patent: US 7,566,273 B2
• Time in Patent Office: Days
• US Class Current: 463/30
• CPC Class Codes: A63F 2300/66 for rendering three dimensional images
• CPC Class Codes: A63F 2300/8017 Driving on land or water; Flying
• CPC Class Codes: G06T 15/005 General purpose rendering architectures
• CPC Class Codes: G06T 15/04 Texture mapping
• CPC Class Codes: G06T 15/40 Hidden part removal
• CPC Class Codes: G06T 15/405 using Z-buffer
• CPC Class Codes: G06T 15/503 Blending, e.g. for anti-aliasing
• CPC Class Codes: G06T 2207/10024 Color image
• CPC Class Codes: G06T 5/20 using local operators
• CPC Class Codes: G06T 5/70 Denoising; Smoothing
• CPC Class Codes: G06T 5/92 based on global image properties
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 2340/02 Handling of images in compressed format, e.g. JPEG, MPEG
• CPC Class Codes: G09G 2340/10 Mixing of images, i.e. displayed pixel being the result of an operation, e.g. adding, on the corresponding input pixels
• CPC Class Codes: G09G 5/022 using memory planes
• CPC Class Codes: G09G 5/06 using colour palettes, e.g. look-up tables
• CPC Class Codes: G09G 5/36 characterised by the display of a graphic pattern, e.g. using an all-points-addressable [APA] memory

Abstract

An objective of the present invention is to provide a game system, program and image generating method which can generate a more realistic image with reduced processing load by using an alpha value set depending on a depth value. Z-value for each pixel in an original image is transformed into Z2-value that is formed of bits I to J which are positioned lower than the most significant bit in the Z-value. The alpha value for each pixel is set at a value corresponding to the Z2-value. Representation of the depth of field or fog image is enabled by using the alpha value to generate an image. The Z2-value is clamped to a given value depending on a bit value other than the bits I to J of the Z-value. Bits M to N and K to L (where K≧I≧L>M≧J≧N) in the Z-value are set as index numbers in LUT1 and LUT2 and used to perform texture mapping for transforming the Z-value into Z3- and Z4-values. These Z3- and Z4-values are used to determine the Z2-value.

Claims

1. A game system which generates an image, comprising:

means which transforms a depth value of each pixel of an original image into a second depth value formed of lower bits I to J which are positioned lower than the most significant bit of the depth value;

means which sets an alpha value of each pixel to a value corresponding to the second depth value; and

means which generates an image based on the set alpha value.

2. The game system as defined in claim 1,

wherein the original image is blended with a defocused image of the original image based on the alpha value set for each pixel.

3. The game system as defined in claim 2,

wherein the defocused image of the original image is generated by setting the original image as a texture and shifting texture coordinates of a virtual object when the texture is mapped onto the virtual object by texel interpolation method.

4. The game system as defined in claim 1,

wherein the second depth value is clamped into a given value depending on a bit value other than the bits I to J in the depth value.

5. The game system as defined in claim 1,

wherein the depth value is set as an index number in a lookup table for index color texture-mapping;

and

wherein the depth value is transformed into the second depth value by performing index color texture-mapping on a virtual object by using the lookup table.

6. The game system as defined in claim 1, wherein:

bits M to N in the depth value are set as an index number in a first lookup table for index color texture-mapping;

the depth value is transformed into a third depth value by performing index color texture-mapping on a virtual object by using the first lookup table;

bits K to L (where K≧

I≧

L>

M≧

J≧

N) in the depth value are set as an index number in a second lookup table for index color texture-mapping;

the depth value is transformed into a fourth depth value by performing index color texture-mapping on a virtual object by using the second lookup table; and

the third and fourth depth values are used to determine the second depth value.

8. The game system as defined in claim 5,

wherein the virtual object is a polygon having a size equal to a size of a display screen.

10. The game system as defined in claim 5,

wherein the virtual object is a polygon having a size equal to a size of a block obtained by dividing a display screen into blocks.

7. A game system which generates an image, comprising:

means which sets bits M to N in given image information as an index number in a first lookup table for index color texture-mapping, and uses the first lookup table to perform index color texture-mapping on a virtual object to transform the image information into third image information;

means which sets bits K to L in the image information as an index number in a second lookup table for index color texture-mapping, and uses the second lookup table to perform index color texture-mapping on a virtual object to transform the image information into fourth image information; and

means which determines second image information formed of the bits I to J (where K≧

I≧

L>

M≧

J≧

N) in the image information based on the third and fourth image information.

9. The game system as defined in claim 7,

wherein the virtual object is a polygon having a size equal to a size of a display screen.

11. The game system as defined in claim 7,

wherein the virtual object is a polygon having a size equal to a size of a block obtained by dividing a display screen into blocks.

13. The program as defined in claim 12,

wherein the original image is blended with a defocused image of the original image based on the alpha value set for each pixel.

14. The program as defined in claim 13,

wherein the defocused image of the original image is generated by setting the original image as a texture and shifting texture coordinates of a virtual object when the texture is mapped onto the virtual object by texel interpolation method.

15. The program as defined in claim 12,

wherein the second depth value is clamped into a given value depending on a bit value other than the bits I to J in the depth value.

16. The program as defined in claim 12,

wherein the depth value is set as an index number in a lookup table for index color texture-mapping;

and

wherein the depth value is transformed into the second depth value by performing index color texture-mapping on a virtual object by using the lookup table.

17. The program as defined in claim 12, wherein:

bits M to N in the depth value are set as an index number in a first lookup table for index color texture-mapping;

the depth value is transformed into a third depth value by performing index color texture-mapping on a virtual object by using the first lookup table;

bits K to L (where K≧

I≧

L>

M≧

J≧

N) in the depth value are set as an index number in a second lookup table for index color texture-mapping;

the depth value is transformed into a fourth depth value by performing index color texture-mapping on a virtual object by using the second lookup table; and

the third and fourth depth values are used to determine the second depth value.

19. The program as defined in claim 16,

wherein the virtual object is a polygon having a size equal to a size of a display screen.

20. The program as defined in claim 18,

wherein the virtual object is a polygon having a size equal to a size of a display screen.

21. The game system as defined in claim 16,

wherein the virtual object is a polygon having a size equal to a size of a block obtained by dividing a display screen into blocks.

22. The program as defined in claim 18,

wherein the virtual object is a polygon having a size equal to a size of a block obtained by dividing a display screen into blocks.

24. The method as defined in claim 23,

wherein the original image is blended with a defocused image of the original image based on the alpha value set for each pixel.

25. The method as defined in claim 24,

wherein the defocused image of the original image is generated by setting the original image as a texture and shifting texture coordinates of a virtual object when the texture is mapped onto the virtual object by texel interpolation method.

26. The method as defined in claim 23,

wherein the second depth value is clamped into a given value depending on a bit value other than the bits I to J in the depth value.

27. The method as defined in claim 23,

wherein the depth value is set as an index number in a lookup table for index color texture-mapping;

and

wherein the depth value is transformed into the second depth value by performing index color texture-mapping on a virtual object by using the lookup table.

28. The method as defined in claim 23, wherein:

bits M to N in the depth value are set as an index number in a first lookup table for index color texture-mapping;

the depth value is transformed into a third depth value by performing index color texture-mapping on a virtual object by using the first lookup table;

bits K to L (where K≧

I≧

L>

M≧

J≧

N) in the depth value are set as an index number in a second lookup table for index color texture-mapping;

the depth value is transformed into a fourth depth value by performing index color texture-mapping on a virtual object by using the second lookup table; and

the third and fourth depth values are used to determine the second depth value.

30. The method as defined in claim 27,

wherein the virtual object is a polygon having a size equal to a size of a display screen.

31. The method as defined in claim 29,

wherein the virtual object is a polygon having a size equal to a size of a display screen.

32. The method as defined in claim 27,

wherein the virtual object is a polygon having a size equal to a size of a block obtained by dividing a display screen into blocks.

33. The method as defined in claim 29,

wherein the virtual object is a polygon having a size equal to a size of a block obtained by dividing a display screen into blocks.

12. A computer-usable program embodied on an information storage medium or in a carrier wave, comprising a processing routine for a computer to realize:

means which transforms a depth value of each pixel of an original image into a second depth value formed of lower bits I to J which are positioned lower than the most significant bit of the depth value;

means which sets an alpha value of each pixel to a value corresponding to the second depth value; and

means which generates an image based on the set alpha value.

18. A computer-usable program embodied on an information storage medium or in a carrier wave, comprising a processing routine for a computer to realize:

means which sets bits M to N in given image information as an index number in a first lookup table for index color texture-mapping, and uses the first lookup table to perform index color texture-mapping on a virtual object to transform the image information into third image information;

means which sets bits K to L in the image information as an index number in a second lookup table for index color texture-mapping, and uses the second lookup table to perform index color texture-mapping on a virtual object to transform the image information into fourth image information; and

means which determines second image information formed of the bits I to J (where K≧

I≧

L>

M≧

J≧

N) in the image information based on the third and fourth image information.

23. A method of generating an image, comprising a step of:

transforming a depth value of each pixel of an original image into a second depth value formed of lower bits I to J which are positioned lower than the most significant bit of the depth value;

setting an alpha value of each pixel to a value corresponding to the second depth value; and

generating an image based on the set alpha value.

29. A method of generating an image, comprising a step of:

setting bits M to N in given image information as an index number in a first lookup table for index color texture-mapping;

using the first lookup table to perform index color texture-mapping on a virtual object to transform the image information into third image information;

setting bits K to L in the image information as an index number in a second lookup table for index color texture-mapping;

using the second lookup table to perform index color texture-mapping on a virtual object to transform the image information into fourth image information; and

determining second image information formed of the bits I to J (where K≧

I≧

L>

M≧

J≧

N) in the image information based on the third and fourth image information.