Recirculating shade tree blender for a graphics system

In a video game system including a processing pipeline that renders and displays images at least in part in response to interactive user inputs and polygon vertex data and texture data stored in an associated memory, a texture processing subsystem for selectively mapping texture data corresponding to one or more different textures and/or texture characteristics to surfaces of said rendered and displayed images, and a texture environment unit for processing input texture and rasterized color data to provide independent mathematical blending operations on said input texture and rasterized color data, a method for processing multiple textures comprising the steps of:

• (a) performing texture mapping during a texture mapping cycle/stage;
• (b) using hardware to perform blending operations on a first set of mapped texture and rasterized color data during a first texture environment unit temporal processing cycle/stage;
• and
• (c) providing an output of said first temporal processing cycle/stage as an input to a subsequent texture environment unit temporal processing cycle/stage that reuses said same hardware to perform additional blending operations,
• wherein the duration of each of said texture environment unit temporal processing cycles/stages is at least twice as short as said texture mapping cycle/stage.

A graphics processing pipeline that renders and displays images at least in part in response to polygon vertex data and texture data, comprising:

• a recirculating texturing arrangement having a single texture address coordinate/data processing unit, a single texture retrieval unit, and a texture lookup data feedback path for recirculating selected retrieved texture lookup data from the texture retrieval unit back to the texture address coordinate/data processing unit;
• and
• a recirculating shade-tree alpha/color blender arrangement having a hardware shader connected to receive an output of the texture retrieval unit and a feedback path from an output of the hardware shader to an input of the shader for recirculating selected blended color or opacity output data, wherein the recirculating arrangement blends selected shader inputs to provide an output that is fed back for use as an input to the shader for a subsequent blending operation,
• wherein said texturing arrangement operates simultaneously with said blender arrangement and said blender arrangement is capable of completing two blending operations for each texture mapping operation said texturing arrangement performs.

In a graphics system, a multitexture processing subsystem comprising:

• a texturing arrangement having a single texture address coordinate/data processing unit, a single texture retrieval unit, and a texture lookup data feedback path for recirculating retrieved indirect texture lookup data from a single texture retrieval unit back to the texture address coordinate/data processing unit;
• and
• a recirculating hardware shader connected to receive an output of the texture retrieval unit, wherein the shader blends selected received outputs to provide a calculated color or opacity output that is selectively fed back for use as an input to the shader for a subsequent blending operation,
• wherein said texturing arrangement operates concurrently with said hardware shader and said hardware shader can complete two blending operations for each texture operation said texturing arrangement performs.