Methods and tiling engines for hierarchically tiling primitives in a graphics processing system

摘要

Tiling engine and methods of use in a graphics processing system which involves hierarchically tiling and rendering primitives (geometries e.g triangles) within a Hybrid Tile Based Renderer (TBR). The tiling engine includes: a chain of sorting units comprising a top level sorting unit (404 fig 1) followed by one or more lower level sorting units (410), wherein: the top level sorting unit determines which regions of render space (500) each primitive (A,B), at least partially, falls within (occupies); and for each identified region, store an identifier (A or B) of that primitive in a top level sorting unit queue (or buffer) 510,512,514,516: each of the lower level sorting units is configured to select one or more queues of a preceding sorting unit in the chain to process and for each queue, determine which of a plurality of sub-regions (patches) of the queue region at least partially, falls within and to store a primitive identifier (A or B) in a lower level queue 710,712,714,716 associated with this sub-region: and an output unit configured to output the primitives identified in the queues of the last lower level sorting unit in the chain on a queue by queue basis. The top-level sorting unit may deploy a boundary box method of primitive occupancy assessment whilst the lower level sorting unit may deploy a more accurate method. The tiler or rendering engine is particularly applicable to mobile handheld units due to the efficient use of memory.