GRAPHICS PROCESSING SYSTEMS

摘要

When sampling a cube map when rendering in a graphics processing system, the vector representation of the desired cube map sample provided by the application is converted into a 2D position on one of the faces of the cube map for use by the texturing unit of the graphics processing pipeline.;The determined 2D texture coordinates (S, T) are represented using standard 32-bit IEEE 754 floating point numbers, and the 3-bit face index for the cube map is included in one of the numbers representing the texture coordinates by packing it into the sign bit and the top two bits of the exponent to provide a modified texture coordinate value.;The modified 32-bit texture coordinate representation is then provided together with the 32-bit floating point number corresponding to the other texture coordinate as the cube map descriptor to the texturing unit of the graphics processing pipeline.

主权项

1. A method of operating a graphics processing system when using a multi-face texture that is sampled using a direction vector from a reference position that the texture is defined with respect to, the method comprising:
determining from a direction vector that indicates a desired sampling position of the multi-face texture, the face of the texture that is to be sampled and a pair of texture coordinates indicating the position to be sampled in the determined face; representing each determined texture coordinate using a predefined format for representing numbers of the graphics processing system; and using one or more of the bits of the representations of the texture coordinates to indicate the face of the texture that is to be sampled.