"Unity3D ShaderLab explain the development of actual combat" in Chapter 6 VertexLit rendering path

Shader variable seed light source 3

• The first:
  • _WorldSpaceLightPos0: w is 0 to parallel light, w is 1 is a point light.
  • _LightColor0: Color.
• The second:
  • float4 unity_4LightPos {X / Y / Z} 0: four point light source position (world space).
  • float4 unity_4LightAtten0: 4 light sources attenuation.
  • float4 unity_LightColor [4]: ​​4 color light sources.
• The third
  • float4 unity_LightPosition [4]: ​​4 parallel light / spot light source position (eye space).
  • float4 unity_LightColor [4]: ​​4 parallel light / spot light color.
  • float4 unity_LightAtten [4]: ​​4 parallel light / spot light attenuation.

Different paths, the light source under different variables LightMode

Model \ path	Variable light source	Vertex path	Forward path	Deferred path
Vertex	_WorldSpaceLightPos0	Important parallel light	Same as above	Same as above
	unity_4LightPos{X/Y/Z}0	A point light source (first important)	Same as above	Same as above
	unity_LightPosition	Important light source (preferentially parallel light), if the scene is not important light source, the light source is parallel	Same as above	Same as above
ForwardBase	_WorldSpaceLightPos0	no	Important parallel light	Same as above
	unity_4LightPos{X/Y/Z}0	no	Point source (important priority), if there is ForwardAdd Pass then it is all important sources of	Same as above
	unity_LightPosition	no	no	no
ForwardAdd	_WorldSpaceLightPos0	no	Important sources (performed once for each source Pass)	Same as above
	unity_4LightPos{X/Y/Z}0	no	Important point light source	Same as above
	unity_LightPosition	no	no	no
Deferred	_WorldSpaceLightPos0	no	no	Important parallel light
	unity_4LightPos{X/Y/Z}0	no	no	A point light source
	unity_LightPosition	no	no	no

This table Deferred still a little problem, after detailed investigation capacity ...