Method and apparatus for mapping texture

• US 5,933,148 A
• Filed: 11/30/1995
• Issued: 08/03/1999
• Est. Priority Date: 12/02/1994
• Status: Expired due to Term

• Current Assignee: Sony Computer Entertainment Incorporated (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Oka, Masaaki, Suzuoki, Masakazu
• Primary Examiner(s): Fetting, Anton
• Application Number:
  US08/565,719
• Time in Patent Office: 1,342 Days
• Field of Search: 395/130, 395/129, 395/118, 395/126, 345/418, 345/423, 345/429, 345/427, 345/430
• US Class Current: 345/427
• CPC Class Codes: G06T 15/04 Texture mapping
• CPC Class Codes: G06T 3/4007 based on interpolation, e.g. bilinear interpolation image demosaicing G06T3/4015; edge-driven or edge-based scaling G06T3/403

Abstract

In a real-time texture mapping system, a more solid and naturally-mapped image is obtained with a minimum of computation volume. The texture-mapping system adds a texture image to an area of a polygon which forms a fundamental unit of three-dimensional image information of an object to be displayed on a screen. A geometry transfer engine (GTE) 61 extracts representing points from the polygonal area. Then, coordinates of the thus extracted representing points are subjected to the perspective transformation. Thereafter, the representing points, after the perspective transformation, are subjected to the linear interpolation in a graphic processing unit (GPU) 62 so that the image is formed.

Claims

1. A method for producing a polygon image, comprising the steps of:

(a) storing a texture pattern in a memory device;

(b) carrying out a perspective transformation upon the vertices of said polygon image;

(c) generating representing points based on said vertices of said polygon image, each of said representing points being included in the area of said polygon image forming a fundamental unit of information in a three dimensional image object to be graphically displayed;

(d) when a plurality of representing points are generated, carrying out a perspective transformation upon said representing points;

(e) generating a display command for one or more polygons respectively; and

(f) specifying a texture pixel read out from said memory device corresponding to the interpolation of said representing points based on said respective display command.

2. The method as set forth in claim 1 further comprising the step of:

mapping said texture pixel on said polygon image.

3. The method as set forth in claim 1, wherein said generating step selects the number of said representing points in response to the size of said polygon image.

4. The method as set forth in claim 1, wherein said generating step selects the positions of said representing points in response to the area of said polygon image.

5. The method as set forth in any of claims 1-4 further comprising the step of performing linear interpolation upon said representing points, whereby distortion is minimized.

6. The method as set forth in claim 1, wherein said specifying step specifies the texture pixel read out from said memory device corresponding to each linearly interpolated point which is transformed.

7. The method as set forth in claim 1 wherein said perspective-transformed vertices and said perspective-transformed representing points define one or more sub-polygons which form said polygon image and said step of generating a display command comprises the step of generating a display command for each sub-polygon.

8. The method as set forth in claim 1 wherein the number of representing points is less than the number of points included in a line between said vertices of said polygon image.

9. The method as set forth in claim 1 further comprising the step of storing image data in said memory device.

10. An apparatus for producing a polygon image, said apparatus comprising:

(a) a memory device for storing a texture pattern;

(b) a first generating device for generating representing points based on said vertices of said polygon image, each of said representing points being included in the area of said polygon image forming a fundamental unit of information in a three dimensional image object to be graphically displayed;

(c) a converting device for carrying out a perspective transformation upon said vertices and for carrying out a perspective transformation upon said representing points when a plurality of representing points are generated;

(d) a second generating device for generating a display command for one or more polygons respectively; and

(e) a specifying device for specifying a texture pixel read out from said memory device corresponding to the interpolation of said representing points based on said display command.

11. The apparatus as set forth in claim 10, and further comprising:

a drawing device for mapping said texture pixel on said polygon image.

12. The apparatus as set forth in claim 10, wherein said first generating device selects the number of said representing points in response to the size of said polygon.

13. The apparatus as set forth in claim 10, wherein said first generating device selects the positions of said representing points in response to the area of said polygon image.

14. The apparatus as set forth in claim 10, wherein said specifying device specifies the texture pixel read out from said memory device corresponding to each linearly interpolated point which is transformed.

15. The apparatus as set forth in any of claims 10-14 wherein said apparatus includes an interpolation device for performing linear interpolation upon said representing points, whereby distortion is minimized.

16. The apparatus as set forth in claim 10 wherein said perspective-transformed vertices and said perspective-transformed representing points define one or more sub-polygons which form said polygon image and said second generating device generates a display command for each sub-polygon.

17. The apparatus as set forth in claim 10 wherein the number of representing points is less than the number of points included in a line between said vertices of said polygon image.

18. The apparatus as set forth in claim 10 wherein said memory device also has an area for storing an image data to be displayed.

19. An apparatus for mapping texture stored in a memory device to a polygonal area, said apparatus comprising:

a representing-point extracting device for extracting representing points from said polygonal area wherein said representing points include non-vertex points, said representing points being extracted based on the vertices of said polygonal area and included in said polygonal area forming a fundamental unit of information in a three dimensional image object to be graphically displayed;

a perspective-transformation device for performing a perspective transformation of the coordinates of said representing points which have been extracted through said representing-point extracting device when a plurality of representing points are extracted; and

a linear-interpolation device for performing a linear interpolation between said representing points which have been subjected to said perspective transformation through said perspective-transformation device;

whereby image information, in which said texture is added to said polygonal area, is obtained as an interpolation output issued from said linear-interpolation device with a minimum of distortion and reduced computation.

20. The apparatus, as set forth in claim 19, wherein the number of said representing points extracted by said representing-point extracting device varies in accordance with the size of said polygonal area.

21. A method for processing image data to form a polygon image, said method comprising the steps of:

storing image data including three-dimensional coordinates of image points;

extracting representative coordinates for representing points in said image data in addition to said three-dimensional coordinates in said image data, said representing points being non-vertex points and extracted based on the vertices of said polygonal area and included in the area of said polygon image forming a fundamental unit of information in a three dimensional image object to be graphically displayed, said representing points for minimizing image distortion normally resulting from coordinate transformation; and

linearly interpolating and transforming said image data and linearly interpolating and transforming said representing points when a plurality of representing points are extracted, to convert said three-dimensional coordinates of image points and said additional representative coordinates to two-dimensional image data with a minimum of distortion requiring minimum computation.

22. A method of processing image data to form a polygon image, said method comprising the steps of:

(a) storing one or more texture data;

(b) extracting representing points from said polygon based on the vertices of said polygon;

c) carrying out a perspective transformation upon said vertices and carrying out a perspective transformation upon said representing points when a plurality of representing points are extracted;

(d) generating an image-forming list for the respective new polygons defined by said vertices and said representing points respectively; and

(e) executing a texture mapping process using one of said texture data based on said image-forming list.