US 6,288,730 B1Granted

Method and apparatus for generating texture

AssigneeApple Computer, Inc.

InventorsJerome F. Duluk, Jr., Richard E. Hessel, Joseph P. Grass, Abbas Rashid, Bo Hong, Abraham Mammen

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Abstract

A deferred graphics pipeline processor comprising a texture unit and a texture memory associated with the texture unit. The texture unit applies texture maps stored in the texture memory, to pixel fragments. The textures are MIP-mapped and comprise a series of texture maps at different levels of detail, each map representing the appearance of the texture at a given distance from an eye point. The texture unit performs tri-linear interpolation from the texture maps to produce a texture value for a given pixel fragment that approximates the correct level of detail. The texture memory has texture data stored and accessed in a manner which reduces memory access conflicts and thus improves throughput of said texture unit.

Claims39

Dependent claims

A graphics pipeline processor comprising:

a texture unit generating texture values;
and
a texture memory associated with and coupled to said texture unit;
said texture unit interpolating a plurality of MIP-mapped texture maps stored in said texture memory at different levels of detail to produce a texture value for a given pixel fragment that approximates the correct level of texture detail each of the levels of detail including an array of texels grouped into texel blocks and applying said interpolated texture value to pixel fragments;
each of the levels of detail including an array of texels grouped into texel blocks, each texture map representing the appearance of the texture at a given distance from an eye point;
a texel prefetch buffer storing prefetched texel blocks previously read from said texture memory;
and
a prefetch tag memory storing tags corresponding to the prefetched texel blocks and used to determine which of the texel blocks are stored in the texel prefetch buffer in order to avoid re-reading a previously read one of the texel blocks from the texture memory;
said tags indicating whether a texel block is stored in the texel prefetch buffer and indicating the location of the texel block in the texel prefetch buffer, the prefetch buffer tag blocks checking a plurality of texture addresses against the stored tags thereby checking for a match, each tag comprising (1) the texture identifier;
(2) the level of detail indicator;
(3) the texture U-coordinate of the stored texel block;
and (4) the texture V-coordinate of the stored texel block;
said texture memory, said texel prefetch buffer, and said prefetch tag memory storing and accessing texture data so that memory access conflicts are reduced and throughput of said texture unit is increased.

10 more elements

A texture device for a graphics rendering pipeline, the pipeline receiving a plurality of graphics primitives and generating a rendered image, at least some of the graphics primitives being rendered with at least one texture map, the texture device comprising:

logic receiving texture coordinates corresponding to a pixel fragment;
bank mapping logic translating each of the texture coordinates to a plurality of texture tile addresses, each of the texture tile addresses comprising:
(1) a texture identifier;
(2) a level of detail indicator;
(3) a texture U-coordinate of the stored texture element (texel) block;
and (4) a texture V-coordinate of the stored texel block;
a texture memory storing the texture maps, each of the texture maps being an array of texels, the texels grouped into texel blocks;
a texel prefetch buffer storing prefetched texel blocks, the prefetched texel blocks being the texel blocks read from the texture memory, the texel prefetch buffer organized into a plurality of banks, the number of the banks within the texel prefetch buffer being an integer multiple of the number of texels in the texel block, the texels in any of the prefetched texel blocks being stored in separate ones of said banks, the banks operating in parallel;
a plurality of prefetch buffer tag blocks storing tags, the tags each corresponding to one stored texel block, the tags indicating whether a texel block is stored in the texel prefetch buffer and indicating the location of the texel block in the texel prefetch buffer, the prefetch buffer tag blocks checking the plurality of texture tile addresses against the stored tags in one clock cycle thereby checking for a match, each tag comprising (1) the texture identifier;
(2) the level of detail indicator;
(3) the texture U-coordinate of the stored texel block;
and (4) the texture V-coordinate of the stored texel block;
and
prefetch buffer control logic reading the stored texel blocks from the texture memory when the checking does not indicate a needed texel block is not in the texel prefetch buffer.

11 more elements

A graphics rendering pipeline generating a rendered image from a plurality of graphics primitives, the pipeline comprising:

a hidden surface removal block determining, for each sample in the rendered image, a set of visible graphics primitives from the plurality of graphics primitives, the determining being done before any pixel coloring is done, wherein one or more of the samples from a single visible graphics primitive and within a pixel are grouped together in a visible fragment;
and
a texture block generating texture values, the texture block comprising:
a texture memory storing texture maps, each texture map comprising a plurality of levels of detail, each of the level of detail being an array of texels, the texels grouped into texel blocks, each texel block being a two-by-two cluster of texels;
logic receiving texture coordinates corresponding to a visible fragment;
a texel prefetch buffer storing prefetched texel blocks, the prefetched texel blocks being the texel blocks read from the texture memory;
and
a prefetch tag memory storing tags corresponding to the prefetched texel blocks, the tags used to determine which of the texel blocks are stored in the texel prefetch buffer in order to avoid re-reading a previously read one of the texel blocks from the texture memory, the tags configured to allow the prefetched texel blocks to be independently prefetched from any texture map and any level of detail, the independence being achieved by the tags being comprised of:
(1) a texture identifier;
(2) a level of detail indicator;
(3) a texture U-coordinate of the stored texel block;
and (4) a texture V-coordinate of the stored texel block.

9 more elements

A texture method for a graphics rendering pipeline, the pipeline receiving a plurality of graphics primitives and generating a rendered image, at least some of the graphics primitives being rendered with at least one texture map, the method comprising the steps:

storing the texture maps in a texture memory, each of the texture maps being an array of texels, the texels grouped into texel blocks;
receiving texture coordinates corresponding to a pixel fragment;
translating each of the texture coordinates to a plurality of texture tile addresses, each of the texture tile addresses comprising:
(1) a texture identifier;
(2) a level of detail indicator;
(3) a texture U-coordinate of the stored texture element (texel) block;
and (4) a texture V-coordinate of the stored texel block;
storing prefetched texel blocks in a texel prefetch buffer, the prefetched texel blocks being the texel blocks read from the texture memory, the texel prefetch buffer organized into a plurality of banks, the number of the banks within the texel prefetch buffer being an integer multiple of the number of texels in the texel block, the texels in any of the prefetched texel blocks being stored in separate ones of said banks, the banks operating in parallel;
storing tags in a plurality of prefetch buffer tag blocks, the tags each corresponding to one stored texel block, the tags indicating whether a texel block is stored in the texel prefetch buffer and indicating the location of the texel block in the texel prefetch buffer, the prefetch buffer tag blocks checking the plurality of texture tile addresses against the stored tags in one clock cycle thereby checking for a match, each tag comprising (1) the texture identifier;
(2) the level of detail indicator;
(3) the texture U-coordinate of the stored texel block;
and (4) the texture V-coordinate of the stored texel block;
and
reading the stored texel blocks from the texture memory when the checking does not indicate a needed texel block is not in the texel prefetch buffer.

11 more elements

In a graphics pipeline processor, a method for generating texture values associated with pixels or pixel fragments, said method comprising:

storing a plurality of texture maps in a texture memory, each of said plurality of texture maps including an array of texels grouped into texel blocks;
reading a texel block from said texture memory;
storing said read texel block in a texel prefetch buffer;
storing tags corresponding to the texel blocks in a prefetch tag memory;
said tags indicating whether a texel block is stored in the texel prefetch buffer and indicating the location of the texel block in the texel prefetch buffer, the prefetch buffer tag blocks checking a plurality of texture addresses against the stored tags thereby checking for a match, each tag comprising:
(1) the texture identifier;
(2) the level of detail indicator;
(3) the texture U-coordinate of the stored texel block;
and (4) the texture V-coordinate of the stored texel block;
querying said tags prior to reading said texture memory to determine which of the texel blocks requested to be read are already stored in the texel prefetch buffer;
retrieving said texel blocks preferentially from said texel prefetch buffer when so stored and from said texture memory when not so stored in order to avoid re-reading a previously read one of the texel blocks from said texture memory;
and
processing said retrieved texel blocks to generate said texture value.

10 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/378,408Filed 20 Aug 1999 · us provisional application
Priority: 20 Aug 1998
Granted: 11 Sep 2001
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

G06T 15/20
Geometric effects: perspective computation
G06T 1/60
General purpose image data processing: memory management
G06T 11/10
Two-dimensional [2D] image generation: texturing; Colouring; Generation of textures or colours
G06T 11/40
Two-dimensional [2D] image generation: filling planar surfaces by adding surface attributes, e.g. adding colours or textures