Category is a logical grouping of any commands below it. This is mostly used to “inherit” renderingThe process of drawing graphics to the screen (or to a render texture). By default, the main camera in Unity renders its view to the screen. More info
See in Glossary state. For example, your shaderA small script that contains the mathematical calculations and algorithms for calculating the Color of each pixel rendered, based on the lighting input and the Material configuration. More info
See in Glossary might have multiple subshadersEach shader in Unity consists of a list of subshaders. When Unity has to display a mesh, it will find the shader to use, and pick the first subshader that runs on the user’s graphics card. More info
See in Glossary, and each of them requires fogA post-processing effect that overlays a color onto objects depending on the distance from the camera. Use this to simulate fog or mist in outdoor environments, or to hide clipping of objects near the camera’s far clip plane. More info
See in Glossary to be off, blending set to additive, etc. You can use Category for that:
Shader "example" {
Category {
Fog { Mode Off }
Blend One One
SubShader {
// ...
}
SubShader {
// ...
}
// ...
}
}
Category block only affects shader parsing, it’s exactly the same as “pasting” any state set inside Category into all blocks below it. It does not affect shader execution speed at all.