Computing system parallelizing the operation of multiple graphics processing pipelines (GPPLs) and supporting depth-less based image recomposition

Abstract

A computing system capable of parallelizing the operation of multiple graphics processing pipelines (GPPLs), The computing system includes a parallel graphics processing subsystem (PGPS) supporting an object-division mode of parallel operation, including at least four stages, namely, decomposition, distribution, rendering and recomposition. The PGPS includes a z-buffering mechanism, wherein the frame buffer has a color value for each pixel, and the z-depth buffer has the same number of entries as the color frame buffer, and stores a z-value for each pixel in the color frame buffer. The z-buffer is initialized to zero, representing the z-value at the back clipping plane of the 3D scene, and the frame buffer is initialized to the background color. The largest value that can be stored in the z-buffer represents the z value of the front clipping plane.

1 - 180 . (canceled) 
     
     
         181 . A computing system capable of parallelizing the operation of multiple graphics processing pipelines (GPPLs), said computing system comprising:
 memory space for storing one or more graphics-based applications, and a graphics library for generating a stream of graphics commands and data (GCAD) during the execution of the graphics-based applications;   one or more CPUs, in communication with said memory space, for (i) executing said graphics-based applications, (ii) generating said stream of graphics commands and data, and (iii) segmenting said stream of graphics commands into frames for rendering pixel-based images of a 3D scene generated by at least one said graphics-based application, and wherein objects within said 3D scene are generated by processing said frames of graphics commands and data along said stream;   a parallel graphics processing subsystem (PGPS) supporting an object-division mode of parallel operation including at least four stages, namely, decomposition, distribution, rendering and recomposition;   wherein said PGPS includes:   (i) a plurality of graphic processing pipelines (GPPLs), including a primary GPPL, wherein each said GPPL includes a color frame buffer and Z depth buffer; and   (ii) a parallel mode control module (PMCM) for automatically controlling said object-division mode of parallel operation during the run-time of said graphics-based application, during which said GPPLs are driven in a parallelized manner and performing the following graphics processing operations:   (i) decomposing objects in each frame of said stream of graphics commands and data, assigning the objects to particular GPPLs for use in rendering operations;   (ii) distributing objects to said GPPLs;   (iii) rendering a partial complementary-type color image of the 3D scene within each GPPL, and buffering the partial complementary-type color image within the color frame buffer in said GPPL, and   (iv) recompositing a complete color image of the 3D scene, and buffering said complete color image in the color frame buffer of said primary GPPL for display on a display device;   wherein said color frame buffer has a color value for each pixel, and   wherein said z-depth buffer has the same number of entries as said color frame buffer, and stores a z-value for each pixel in the color frame buffer; and   wherein the z-buffer is initialized to zero, representing the z-value at the back clipping plane of the 3D scene;   wherein the frame buffer is initialized to the background color; and   wherein the largest value that can be stored in the z-buffer represents the z value of the front clipping plane.   
     
     
         182 . The computing system of  claim 181 , wherein polygons compositing the 3D scene are scan converted into the frame buffer in an arbitrary order, and wherein during the scan-conversion process, if the polygon being scan converted at point (x,y) is no farther from the viewer than the point whose color and depth are currently in the buffers, then the color and depth values of the new point is used to replace the old color and depth values stored at the point (x,y). 
     
     
         183 . The computing system of  claim 181 , wherein said recompositing said complete color image of the 3D scene, is carried out by merging the partial complementary-type color images within said GPPLs employing a depthless method of image recomposition not involving the comparison of depth values stored in said z depth buffers. 
     
     
         184 . The computing system of  claim 181 , wherein said PGPS further includes:
 (i) a decomposition module for supporting the decomposition stage of parallel operation;   (ii) a distribution module for supporting the distribution stage of parallel operation;   (iii) a recomposition module for supporting the recomposition stage of parallel operation; and   (iv) a rendering module for supporting the rendering stage of parallel operation.   
     
     
         185 . The computing system of  claim 184 , wherein said PMCM and said decomposition module and distribution module resides as a software package in said memory space; and said GPPLs on said external graphics cards are (i) connected to said bridge circuit, (ii) implement said rendering and recomposition modules, and (iii) driven in a parallelized manner under the control of said PMCM. 
     
     
         186 . The computing system of  claim 184 , wherein during operation,
 (i) said decomposition module divides the stream of graphic commands and data (GCAD) according to said object-division mode of parallel operation;   (ii) said distribution module uses said bridge circuit to distribute graphic commands and data (GCAD) to said GPPLs;   (iii) said rendering module generates complementary-type partial color images according to a parallel multi-pass graphics processing method; and   (iv) said recomposition module uses inter-GPPL communication to transfer the pixel data of said complementary-type partial images among said GPPLs, and a depthless image merging process to generate said complete color image of the 3D scene for display on said display device.   
     
     
         187 . The computing system of  claim 184 , wherein each said GPPL is a GPU-based graphics processing pipeline which comprises (i) a video memory structure supporting a frame buffer (FB) including stencil, depth and color buffers, and (ii) a graphics processing unit (GPU) supporting ( 1 ) a geometry subsystem having an input assembler and a vertex shader, (2) a set up engine, and (3) a pixel subsystem including a pixel shader receiving pixel data from the frame buffer and a raster operators operating on pixel data in the frame buffers. 
     
     
         188 . The computing system of  claim 184 , wherein each said GPPL is a GPU-based graphics processing pipeline which comprises (i) a video memory structure supporting a frame buffer (FB) including stencil, depth and color buffers, and (ii) a graphics processing unit (GPU) supporting ( 1 ) a geometry subsystem having an input assembler, a vertex shader and a geometry shader, (2) a rasterizer, and (3) a pixel subsystem including a pixel shader receiving pixel data from the frame buffer and a raster operators operating on pixel data in the frame buffers. 
     
     
         189 . The computing system of  claim 184 , wherein each said GPPL is a CPU-based graphics processing pipeline which comprises (i) a video memory structure supporting a frame buffer including stencil, depth and color buffers, and (ii) a graphics processing pipeline realized by a cell of a multi-core CPU chip, including a plurality of in-order SIMD processors, and optionally, a GPPL-specific extension, namely, a texture sampler that loads texture maps from memory, filters them for level-of-detail, and feeds to pixel processing portion of the pipeline. 
     
     
         190 . The computing system of  claim 185 , wherein the decomposition module supports the scanning of commands, the control of commands, the tracking of objects, the balancing of loads, and the assignment of objects to said GPPLs, 
     
     
         191 . The computing system of  claim 185 , wherein said distribution module supports transmission of graphics data in various modes including CPU-to/from-GPPL, inter-GPPL, broadcast, hub-to/from-CPU, and hub-to/from-CPU and hub-to/from-GPPL. 
     
     
         192 . The computing system of  claim 184 , wherein said graphics data includes data selected from the group consisting of FB data, commands, textures, geometric data and other data. 
     
     
         193 . The computing system of  claim 185 , wherein said recomposition module supports a variety of modes the merging of partial complementary-type images in the color frame buffers of said GPPLs. 
     
     
         194 . The computing system of  claim 193 , wherein said variety of modes of merging said partial complementary-type images includes: merging color frame buffers without z buffers, and merging color buffers using stencil-assisted processing. 
     
     
         195 . A Z-buffering mechanism for use in compositing a 3D scene in a 3D parallel graphics rendering system, comprising a color frame buffer having a color value for each pixel and a z-buffer with the same number of entries is provided for storing a z-value for each pixel in the frame buffer; and wherein the z-buffer is initialized to zero, representing the z-value at the back clipping plane of the 3D scene, wherein the frame buffer is initialized to the background color, and wherein the largest value that can be stored in the z-buffer represents the z value of the front clipping plane. 
     
     
         196 . The Z-buffering mechanism of  claim 193 , wherein polygons compositing the 3D scene are scan converted into the frame buffer in an arbitrary order, and wherein during the scan-conversion process, if the polygon being scan converted at point (x,y) is no farther from the viewer than the point whose color and depth are currently in the buffers, then the color and depth values of the new point is used to replace the old color and depth values stored at the point (x,y).