Applying multiple texture maps to objects in three-dimensional imaging processes

Abstract

Systems and methods for providing multi-pass rendering of three-dimensional objects. A rendering pipeline is used that includes one or more (N) physical texture units and one or more associated frame buffers to emulate a rendering pipeline containing more texture units (M) than are actually physically present (N). Multiple rendering passes are performed for each pixel of a frame. During each texture pass for each pixel of a frame, only N sets of texture coordinates are passed to the texture units. The number of passes required through the pipeline to emulate M texture units is M/N, rounded up to the next integer number of passes. The N texture units of the rendering pipeline perform the look-ups on a given pass for the correspondingly bound N texture maps. The texture values obtained during the texture passes for each pixel are blended by complementary texture blenders to provide composite texture values for each of the pixels of the frame. In successive passes, the frame buffers are used to support any necessary extra temporary data and to store the most current composite texture values for all of the pixels of the frame. The process is repeated until all desired texture maps are applied in order to render the desired three-dimensional object.