Extending the Graphics Pipeline with Adaptive, Multi-Rate Shading

摘要

Due to complex shaders and high-resolution displays (particularlyrnon mobile graphics platforms), fragment shading often dominatesrnthe cost of rendering in games. To improve the efficiency of shadingrnon GPUs, we extend the graphics pipeline to natively supportrntechniques that adaptively sample components of the shading functionrnmore sparsely than per-pixel rates. We perform an extensivernstudy of the challenges of integrating adaptive, multi-rate shadingrninto the graphics pipeline, and evaluate two- and three-rate implementationsrnthat we believe are practical evolutions of modern GPUrndesigns. We design new shading language abstractions that simplifyrndevelopment of shaders for this system, and design adaptiverntechniques that use these mechanisms to reduce the number of instructionsrnperformed during shading by more than a factor of threernwhile maintaining high image quality.