Fillrate

Keywords: Shader complexity, Overdraw

Fillrate is sometimes a concern when you are optimizing a scene with a lot of overdraw. The technical explanation can be found here: https://en.wikipedia.org/wiki/Fillrate

However, in more practical terms fillrate comes into play when you have a bunch of overdraw going on. The overdraw can be optimized by reducing the number of layers, or sprites. But you can also get at the fillrate by reducing the shader complexity of the things that are overdrawing. Now, it's not always the amount of math in the shader that's the problem. It can be the number of texture fetches and without profiling it's very hard to know which.

These days, it's not super common that this is the bottleneck. So, if you run into a fillrate problem, fire up PIX and find out where the problem actually lies. Rule of thumb is to have as few overlapping sprites as possible, but the more of them you need to overlap, the cheaper the shader needs to be.

More info: https://developer.android.com/studio/profile/inspect-gpu-rendering