Download Code Samples [GitHub]
Mobile devices are on the trajectory where they are packing more pixels and screen sizes are getting smaller. This increase in the DPI, coupled with the power constrained environment inherent to mobile devices puts a lot of pressure on reducing pixel shading costs as pixel shading consumes a large amount of power. MSAA provides a neat way to reduce pixel shading without sacrificing image quality. Recently, researchers at Intel came up a with a technique called Coarse Pixel Shading that works like MSAA, but reduces the shading rate below once per pixel. Both Coarse Pixel Shading and MSAA fit well in the forward rendering pipeline but don’t work naturally in the deferred pipeline. Andrew Lauritzen at Intel, had come up with a clever way a few years ago to enable MSAA and deferred shading. We extended his ideas to enable Coarse Pixel Shading in the deferred rendering set-up. With our technique we saw about 40-50% reduction in the shading costs on Intel GPUs with a slight increase in the G-buffer generation time.
This sample was published in GPU Pro 7, which is available to order here.