Shader optimization is the process of improving the performance of shaders, which are programs that calculate various attributes of rendered graphics. Shaders are sent from the CPU to the GPU and affect all pixels on the screen, transforming the geometry or visual traits of on-screen objects and materials. The following are some ways to optimize shaders:

• Precompiling: Shaders can be precompiled and loaded from cache on disk, which can shorten loading times.

• Reducing calculations: The more computations and processing a shader code needs to do, the more it will impact the performance of the game. For example, supporting color per material is nice to make a shader more flexible, but if you always leave that color set to white then useless computations are performed for each vertex or pixel rendered on screen.

• Using built-in functions: Shader hardware can do multiplication, addition, and MAD in one cycle, so using built-in functions can improve performance.

• Avoiding branching: Branching can cause slowdowns, so its best to avoid it if possible.

• Using Uber Shaders: Uber shaders are shaders that are a combination of two or more logically separate effects. They tend to be quite bulky, but they account for a range of use-cases and can lead to better performance.

• Testing on target hardware: Since each time a shader gets compiled, the GPU driver of that specific hardware is what converts the code into actual machine code, its best to test the shader on the hardware you are targeting to know for sure how it will perform.

Developers can use tools like Graphics Frame Analyzer to review shader source code and assembly code to identify inefficiencies in shader execution and change the shader accordingly.