[Unity] Shader - ShaderLab

參考資料：

• ShaderLab syntax: Texture Combiners
  http://docs.unity3d.com/Documentation/Components/SL-SetTexture.html
• ShaderLab syntax: SubShader Tags
  http://docs.unity3d.com/Documentation/Components/SL-SubshaderTags.html
• Noobs Guide To Shaders #1
  http://unitygems.com/noobshader1/
• Unity iOS ShaderLab @ Jessy Catterwaul
  http://youtu.be/1C_-fQRKwG4

相關資料：

• Optimizing Graphics Performance
  http://docs.unity3d.com/Documentation/Manual/OptimizingGraphicsPerformance.html

參考範例：

• http://wiki.unity3d.com/index.php?title=UnlitAlphaWithFade
• shader简单练习，混合两张贴图

人生第一次的shader撰寫XD，超陽春Unlit受擊變色用shader，透過shaderLab簡單的功能只要少少幾行就能完成！呈現的效果為，不受光影響，單一貼圖表現，可以透過Color property的alpha來控制貼圖與color間的混合

●　Opaque版本

Shader "Custom/Unlit Opaque With Color" {
	Properties {
		_Color ("Color (RGB) Blending (A)", Color) = (1,0,0,0)
		_MainTex ("Base (RGB)", 2D) = "white" {}
	}
	SubShader {
		Tags {"RenderType"="Opaque" "IgnoreProjector"="True"}
		Lighting Off
		Cull back
		ZWrite On
		
		Pass {
			SetTexture [_MainTex] {
				ConstantColor [_Color]
				combine constant lerp(constant) texture
			}
		}
		
	}
	FallBack "Unlit/Diffuse"
}

●　Transparent Cutout版本

Shader "Custom/Unlit Transparent Cutout With Color" {
	Properties {
		_Color ("Color (RGB) Blending (A)", Color) = (1,0,0,0)
		_MainTex ("Base (RGB) Trans (A)", 2D) = "white" {}
		_Cutoff ("Alpha cutoff", Range(0,1)) = 0.5
	}
	SubShader {
		Tags {"Queue"="AlphaTest" "IgnoreProjector"="True" "RenderType"="TransparentCutout"}
		Lighting Off
		Cull back
		ZWrite On
		Blend SrcAlpha OneMinusSrcAlpha
		
		Pass {
			Alphatest Greater [_Cutoff]
			SetTexture [_MainTex] {
				ConstantColor [_Color]
				combine constant lerp(constant) texture, texture
			}
		}
		
	}
	FallBack "Unlit/TransparentCutout"
}