Method and apparatus for executing a raster operation in a graphics controller circuit

摘要

A graphics controller circuit comprising a plurality of pipelines for performing a set of operations on a stream of input pixel data to generate at least a first operand and a second operand. A rasterop unit in the graphics controller circuit may receive the first operand and the second operand, and execute a raster operation using the first operand and the second operand to generate a set of display pixel data. The graphics controller circuit may further comprise a transparency unit for generating a write enable mask corresponding to the set of display pixel data. A display memory may selectively store or block the set of display pixel data according to the write enable mask. As the graphics controller generates display signals from the display data stored in display memory, a transparency operation may be performed.