The Shader Permutation Problem - Part 1: How Did We Get Here?
therealmjp.github.ioIt is no secret that we tend to have a bit of a problem with shader permutations in real-time graphics. It’s such a bad problem that it not only affects graphics programmers, but also trickles down to all of the other content creators that use an engine. If you don’t believe me, just go ahead and search for “unreal compiling shaders meme” on Google images and see what comes up. There are many great ones to choose from, but personally I am a bit partial to this one:
Recurrent internet discussions show a divide between programmers working in different industries. Topics like code clarity, performance, debuggability, architecture or maintainability are a source …
Vello is a new GPU accelerated renderer for 2D graphics that relies heavily on compute shaders for its operation. (It was formerly known as piet-gpu, but we renamed it recently because it is no longer based on the [Piet] render context abstraction, and has been substantially rewritten). As such, it depends heavily on having good infrastructure for writing and running compute shaders, consistent with its goals of running portably and reliably across a wide range of GPU hardware. Unfortunately, there hasn’t been a great off-the-shelf solution for that, so we’ve spent a good part of the last couple years building our own hand-rolled GPU abstraction layer, piet-gpu-hal.