1. 什么是Shader
All rendering in Unity is done with Shaders - small scripts that let you configure the how the graphics hardware is set up for rendering.
Shader（着色器）意即：能够使用图形硬件（GPU）来进行渲染工作的脚本。
1.1 Surface Shader
Surface Shaders are your best option if your shader need to be affected by lights and shadows.
NOTE: Do not use Surface shaders if your shader is not doing anything with lights.
1.2 Vertex and Fragment Shaders
When shader doesn‘t nedd to interact with lighting or you need some very exotic effects that the surface shaders can‘t handle, and it comes with a price: you have to write more code and it‘s harder to make it interact with lighting.
1.3 Fixed function Shaders
This type shaders need to be written for old hardware that doesn‘t support programmable shaders.
2. Materials and Shaders
Shaders contain code that define what kind of properties and assets to use. Materials allow you to adjust properties and assign assets.
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