Patent ID: 6433788
Filing Date: 2002-08-13
Classification: G06T

Abstract:
A dual fragment cache pixel processing circuit, comprising:a first fragment cache; a first set of state registers, wherein the first set of state registers stores state variables for drawing operations corresponding to fragments stored in the first fragment cache; a second fragment cache; a second set of state registers, wherein the second set of state registers stores state variables for drawing operations corresponding to fragments stored in the second fragment cache; a control block operably coupled to the first and second fragment caches and the first and second sets of state registers, wherein the control block selects one of the first and second fragment caches as a current fragment cache and selects a corresponding one of the first and second sets of state registers as a current set of state registers, wherein whichever of the first and second fragment caches is not the current fragment cache is a backup fragment cache and whichever of the first and second sets of state registers is not the current set of state registers is a backup set of state registers, wherein the current fragment cache caches receives pixel fragments for processing, wherein when a state change is detected by the control block, the control block exchanges designation of the current fragment cache with the backup fragment cache and exchanges designation of the current set of state registers with the backup set of state registers, wherein the control block flushes newly designated backup fragment caches in preparation for future state changes; a frame buffer that stores current pixel information for a plurality of pixels in a frame; and a render backend block operably coupled to the control block and the frame buffer wherein the render backend block combines fragments received from the control block with portions of the current pixel information retrieved from the frame buffer to produce revised pixel information that is stored in the frame buffer, wherein the render backend block combines the fragments with the current pixel information based on corresponding state variables for the fragments.