Texture mapping system and method using a texture cache for minimum capacity and minimum access time

• US 6,111,585 A
• Filed: 05/14/1998
• Issued: 08/29/2000
• Est. Priority Date: 09/19/1997
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Choi, Sang-gil
• Primary Examiner(s): Powell, Mark R
• Assistant Examiner(s): HAVAN, THU THAO
• Application Number:
  US09/078,809
• Time in Patent Office: 838 Days
• Field of Search: 345/430, 345/440, 345/468, 345/115, 345/118, 345/121, 345/127, 345/501, 345/509, 345/425, 345/426, 345/507, 345/513, 345/433, 382/154
• US Class Current: 345/582
• CPC Class Codes: G06T 15/04 Texture mapping

Abstract

A texture mapping system and a texture mapping method are provided for generating pixels displayed on a screen by texture mapping. The texture mapping system includes a texture cache for storing texture image data fetched from a frame buffer memory with respect to one scanline, in which the texture cache comprises a column structure composed of a tag region where an image coordinate value (u, v) of the texture image data is stored, a refill line region where the texture image data corresponding to the image coordinate value of the tag region is stored, and an effective bit region indicating whether data of the refill line region is accessed. The texture cache also has a row structure in which the number of rows is the same as the number texture image patch data with respect to an image of a maximum length covering at least one scanline to be texture mapped, to store texture image patch data to be texture mapped. Accordingly, by the texture mapping system including a texture cache and a data loading method of the texture cache, texture memory capacitance of the graphic process chip is reduced to reduce chip cost. Further, data access speed is reduced due to cache hit to rapidly perform texture-mapping.

Claims

1. A texture mapping system for generating pixels displayed on a screen by texture mapping, comprising a texture cache for storing texture image data fetched from a frame buffer memory with respect to one scanline, said texture cache comprising:

a column structure including a tag region for storing an image coordinate value (u,v) of the texture image data, a refill line region for storing texture image data corresponding to the image coordinate value of the tag region, and an effective bit region for storing data indicating whether data of the refill line region is used for scanline texture mapping; and

a row structure for storing texture image patch data to be texture mapped, wherein said row structure has a number rows which is equal to the number of texture image patch data with respect to an image of a maximum length covering at least one scanline to be texture mapped.

2. The system of claim 1, wherein the row structure has a number of rows which is 1.5 times the number of maximum texture image patch data corresponding to one scanline to be texture mapped.

3. The system of claim 1, wherein in the refill line region, capacity of one line is determined by a data compression method and a number of bits per pixel (bpp) indicating color and transparency of a texel, and texel data around the image coordinate is stored in each line.

4. The system of claim 1, wherein the effective bit region comprises:

a first effective bit region for storing data indicating whether texture image patch data of the refill line region is used for previous scanline texture mapping; and

a second effective bit region for storing data indicating whether texture image patch data of the refill line region is used for the current scanline texture mapping, and shifting the stored data to the first effective bit region after completion of the current scanline texture mapping.

5. A texture mapping method using texture cache for storing texture image data received from a frame buffer memory to be texture mapped with respect to one scanline image, the method comprising the steps of:

(a) shifting data stored in a second effective bit region of the texture cache, which indicates whether texture image patch data stored in a corresponding texture cache line was used for previous scanline texture mapping, to a first effective bit region in the texture cache and resetting the data of the second effective bit region when texture mapping of a new scanline begins;

(b) determining whether a tag region of the texture cache for storing an image coordinate (u,v) of texel data to be texture mapped contains an address which is same as a (u,v) address generated with respect to one image of a current scanline;

(c) reading texture image patch data around the (u,v) address from the frame memory buffer and storing the texture image patch data in the refill line region where the data of the first effective bit region is reset, if it is determined in step (b) that the tag region does not contain an address which is same as the (u,v) address generated with respect to one image of a current scanline;

(d) reading values of the texture image patch data of the corresponding refill line region and setting data of the second effective bit region of the corresponding line, if it is determined in step (b) that the tag region contains an address same as the (u,v) address generated with respect to one image of the current scanline or after step (c) is performed; and

e) completing texture mapping data access of the current scanline if a pixel to be texture mapped is a last pixel of the current scanline, and repeatedly performing step (b) if the pixel to be texture mapped is not the last pixel of the current scanline.

6. A texture mapping system comprising:

a geometry processor for calculating changes of geometric information on an object to be rendered in a polygon unit, and converting the result to be projected on a screen of a monitor;

a frame buffer memory for storing data corresponding to intensity values of each pixel forming an image;

a texture cache comprising a column structure having a tag region for storing an image coordinate value (u, v) of the texture image data, a refill line region for storing texture image data corresponding to the image coordinate value of the tag region, and an effective bit region for storing data indicating whether data of the refill line region is used for scanline texture mapping, and a row structure for storing texture image patch data to be texture mapped, wherein said row structure has a number rows which is equal to the number of texture image patch data with respect to an image of a maximum length covering at least one scanline to be texture mapped; and

a rasterizer for performing rasterization using a signal generated by the geometry processor and the texture image patch data read from the texture cache.