COMPUTING TESSELLATION COORDINATES USING DEDICATED HARDWARE

摘要

A system and method for performing tessellation of three-dimensional surface patches performs some tessellation operations using programmable processing units and other tessellation operations using fixed function units with limited precision. (u,v) parameter coordinates for each vertex are computed using fixed function units to offload programmable processing engines. The (u,v) computation is a symmetric operation and is based on integer coordinates of the vertex, tessellation level of detail values, and a spacing mode.

主权项

1. A method for performing tessellation operations using a graphics processor, the method comprising:
receiving a set of control points defining a three-dimensional surface patch at the graphics processor; determining tessellation level of detail values for the surface patch, wherein the tessellation level of detail values includes a fractional tessellation level of detail value; interpolating between a first nearest tessellation level of detail value that is less than the fractional tessellation level of detail value and a second nearest tessellation level of detail value that is the same parity as the first nearest tessellation level of detail and that is greater than the fractional tessellation level of detail value to compute (u, v) coordinates for a vertex of the surface patch; and computing vertex attributes for the vertex based on the (u, v) coordinates and the set of control points.