THROWING SHADE

Or how to go from 50 fps to 500 fps with one click

- Ian Evenden

There’s some benchmarking software you may have heard of called 3DMark. It’s on Steam. Recently, it updated its benchmarks to include the 3DMark Mesh Shader Feature Test, which requires a GPU that’s compatible with DirectX 12 Ultimate. The test runs twice, once with mesh shaders disabled, then again with them switched on. In 4K, using an RTX 3080 card, we got a framerate of around 50 fps for the first run, then something closer to 500 fps for the second, with no perceivable difference in what was displayed on the screen. How the heck did that happen?

‘Shaders’ is a term that’s been thrown around in video games for a while now, and while it seems straightforward it’s not exactly obvious. Shaders are programs that run on programmable GPUs (that’s most of them) that control the levels of light, dark, and colour in rendered images. They’re a major part of modern games’ lighting effects, and there are whole shader languages for graphics programmers to, well, program graphics in.

Pixel shaders were the ray tracing of their time – players of The Elder Scrolls III: Morrowind in 2002 may remember being asked whether they wanted to activate pixel shaders. They only worked if you had a high-end graphics card, there was a bit of a performance hit, but they made the water look awesome. Just like ray tracing, then. Modern pixel shaders do a lot, from bump mapping to shadows to the motion blur you turn off in every game.