Effects and shaders
Xenko uses a programmable shading pipeline. You can write custom shaders, create @'SiliconStudio.Xenko.Graphics.Effect's from them, and use them for drawing. The @'SiliconStudio.Xenko.Rendering.EffectSystem' class provides an easy way to load an effect.
Load an effect
Use:
var myEffect = EffectSystem.LoadEffect("MyEffect").WaitForResult();
You can then bind the effect as pipeline state.
An effect also often defines a set of parameters. To set these, you need to bind resources before drawing.
Shaders
Shaders are authored in the Xenko's shading language, which is an extension of HLSL. They provide true composition of modular shaders via inheritance, shader mixins and automatic weaving of shader in-out attributes.
Effects
Effects in Xenko use C#-like syntax to further combine shaders. They provide conditional composition of shaders to generate effect permutations.
As some platforms can't compile shaders at runtime (eg iOS, Android, etc), effect permutation files (.xkeffectlog) are used to enumerate all permutations ahead of time.
Target everything
Xenko shaders are converted automatically to the target graphics platform - either plain HLSL for Direct3D, GLSL for OpenGL, or SPIR-V for Vulkan platforms.
For mobile platforms, shaders are optimized by a GLSL optimizer to improve performance.