Hidden surface removal in graphics processing systems

摘要

Early depth test stages of a graphics processing pipeline broadcast information about fragments having conditional discard tests associated with them and that pass those early depth tests to other stages in the pipeline. The other stages in the pipeline use the early depth test pass information to determine if the processing of any fragments that they are currently processing can be slowed down. If a fragment that triggered the slowing down of the processing of fragments that are already in the pipeline passes all the conditional discard tests it is to be subjected to, a signal that triggers stopping of the processing of the fragments whose processing it had previously slowed down is sent. If the fragment fails a conditional discard test it is to be subjected to, a signal triggering the reviving of the processing of the fragments whose processing it had previously slowed down is sent.

主权项

1. A method of operating a graphics processing pipeline that includes a plurality of processing stages including a rasteriser that rasterises input primitives to generate graphic fragments to be processed, each graphics fragment having one or more sampling points associated with it, and a renderer that processes fragments generated by the rasteriser to generate output fragment data, the method comprising:
performing an early culling test in respect of at least one sampling point associated with a fragment generated by the rasteriser before the fragment is sent to the renderer for processing; and if the at least one sampling point passes the early culling test, sending the fragment onwards for processing and in response to the at least one sampling point passing the early culling test, determining if the processing of another sampling point that is in the graphics processing pipeline should be slowed down.