Method and apparatus for deferred video rendering

• US 6,084,591 A
• Filed: 04/29/1997
• Issued: 07/04/2000
• Est. Priority Date: 04/29/1997
• Status: Expired due to Term

• Current Assignee: ATI Technologies ULC (Advanced Micro Devices, Inc.)
• Original Assignee: ATI Technologies Incorporated (Advanced Micro Devices, Inc.)
• Inventors: Aleksic, Milivoje M.
• Primary Examiner(s): Powell, Mark R.
• Assistant Examiner(s): Nguyen, Kimbinh T.
• Application Number:
  US08/840,400
• Time in Patent Office: 1,162 Days
• Field of Search: 345/422, 345/418, 345/423, 345/429, 345/430, 345/433, 345/440
• US Class Current: 345/422
• CPC Class Codes: G06T 15/405 using Z-buffer

Abstract

A method and apparatus for deferred rendering of pixel information is accomplished by receiving at least a portion of an object element list (Eg. triangle descriptor list) which contains object element descriptor information for each object to be displayed on at least a portion of the display. Upon receiving this information, z-components of each object element (Eg. triangle) is compared with the other object elements based on pixel location. As the comparisons are being made, the identity of an object element that is visible at a particular pixel location (Eg. in the foreground with respect to other objects) is stored in a manner that corresponds with the particular pixel location. Once the z-components for all of the object elements have been compared, the object elements identified in the memory have pixel information generated therefor.

Claims

1. A method for deferred video rendering, the method comprising the steps of:

a) receiving at least a portion of an object element list, wherein the object element list includes an object element identifier and corresponding display parameters for a plurality of object elements to be displayed in at least a portion of a display;

b) determining x and y parameters of an object element of the plurality of object elements from the at least a portion of the object element list;

c) comparing a plurality of z components of the object element with a plurality of stored z components based on x and y coordinates of the at least a portion of the display, wherein the stored z components are stored in a first memory, wherein the entries of the first memory are based on the x and y coordinates;

d) overwriting a stored z component of the stored z components with a z component of the plurality of z components when the z component compares favorably with the stored z component;

e) overwriting a stored object element identifier with an object element identifier of the object element when the z component compares favorably with the stored z component, wherein the object element identifier is stored in an entry of a second memory, wherein entries of the second memory are based on the x and y coordinates; and

f) when the plurality of z components of each of the plurality of object elements has been compared, generating pixel information from the object element identifiers stored in the second memory and the at least a portion of the object element list.

2. The method of claim 1 further comprises, prior to step (a), partitioning the display into a set of tiles, wherein the at least a portion of the display is at least one tile of the set of tiles.

3. The method of claim 1 further comprises receiving color parameters, texture coordinates, slopes of the color parameters, and slopes of the texture coordinates as the corresponding display parameters.

4. The method of claim 1 further comprises, within step (c), utilizing pixel location as the x and y coordinates.

5. The method of claim 1 further comprises, within step (f), rendering color information as at least part of the pixel information.

6. The method of claim 1 further comprise, within step (f), rending texture information as at least part of the pixel information.

9. The method of claim 1 further comprises receiving color parameters, texture coordinates, slopes of the color parameters, and slopes of the texture coordinates as the corresponding display parameters.

7. A method for deferred video rendering, the method comprising the steps of:

a) receiving at least a portion of an object element list, wherein the object element list includes an object element identifier and corresponding display parameters for each object element of a plurality of object elements;

b) comparing z components of each of the plurality of object elements based on pixel display location;

c) storing the z components of one of the plurality of object elements in a plurality of memory locations in a first memory based on priority pixel location, wherein the plurality of memory locations in the first memory are based on the pixel display location;

d) storing an object element identifier of the one of the plurality of object elements in a plurality of memory locations in a second memory, wherein the plurality of memory locations in the second memory are based on the pixel display location;

e) rendering the one of the plurality of object elements on a display based on the object element identifier stored in the second memory and the at least a portion of the object element list.

8. The method of claim 7 further comprises, prior to step (a), partitioning the display into a set of tiles, wherein the at least a portion of the display is at least one tile of the set of tiles.

10. A deferred video rendering system comprising:

first memory that stores at least a portion of an object element list, wherein the object element list includes an object element identifier and corresponding display parameters for a plurality of object elements to be displayed in at least a portion of a display;

second memory that stores current z component information of a current object element, wherein memory locations of the second memory correspond with x and y coordinates of the at least a portion of the display;

third memory that stores current object element identifier of the current object element, wherein memory locations of the third memory correspond with the x and y coordinates of the at least a portion of the display;

processing circuit; and

fourth memory that stores programming instructions that, when read by the processing circuit, causes the processing circuit to (a) determine x and y parameters of an object element of the plurality of object elements from the at least a portion of the object element list;

(b) compare z component information of the object element with the z component information of the current object element based on the x and y coordinates;

(c) overwrite the z component information of the current object element in the second memory with the z component information of the object element when the z component information of the object element compares favorably with the z component information of the current object element; and

(d) overwrite an object element identifier of the current object element in the third memory with an object element identifier of the object element when the z component information of the object information compares favorably with the z component information of the current object element.

11. The deferred video rendering system of claim 10 further comprises, the fourth memory storing additional programming instructions that, when read by the processing circuit, causes the processing circuit to generate pixel information from the object element identifier of the current object stored in the third memory and the at least a portion of the object element list when the z component information of each of the plurality of object elements has been compared.

12. A deferred video rendering system comprising:

Z component memory that stores z component information of a current object element and identity of the current object element;

object element descriptor memory that stores display parameters for at least the current object element;

memory manager operably coupled to the Z component memory and the object element descriptor memory, wherein the memory manager coordinates reading and writing operations of the Z component memory and the object element descriptor memory;

a Z rendering processor which, based on programming instructions, determines the z component information of the current object element based on a comparison of z component information; and

a video rendering processor which, based on programming instructions, generates pixel information based on the display parameters of the current object element.

13. The deferred video rending system of claim 12 fuirther comprises the display parameters including color/light parameters and texture parameters.

14. A computing system comprising:

system memory that stores programming instructions and data;

a central processing unit that, from time to time, generates video data when executing the programming instructions; and

a video graphics circuit operably coupled to receive the video data, wherein the video graphics circuit includes;

Z component memory that stores z component information of a current object element and identity of the current object element;

object element descriptor memory that stores display parameters for at least the current object element;

memory manager operably coupled to the Z component memory and the object element descriptor memory, wherein the memory manager coordinates reading and writing operations of the Z component memory and the object element descriptor memory;

a Z rendering processor which, based on programming instructions, determines the z component information of the current object element based on a comparison of z component information; and

a video rendering processor which, based on programming instructions, generates pixel information based on the display parameters of the current object element.

15. The computing system of claim 14 further comprises, within the video graphics circuit, a video setup processor operably coupled to receive the video data, to the Z rendering processor, and to the object element descriptor memory.

16. The computing system of claim 14 further comprises, within the video graphics circuit, a frame buffer operably coupled to store the pixel information.