透明測試Shader

 

Shader "Chapter8/AlphaTestShader"
{
	Properties
	{
		_Color("Color",Color) = (1,1,1,1)
		_MainTex ("Texture", 2D) = "white" {}
		_Cutoff("_Cutoff",Range(0,1)) = 0.5
		
	}
	SubShader
	{
		Tags{"Queue"="AlphaTest" "IgnoreProjector"="True" "RenderType"="TansparentCutout"}
		Pass{
			Tags{"LightMode" = "ForwardBase"}
			CGPROGRAM

			#program vertex vert
			#program fragment frag
			#include "Lighting.cginc"

			fixed4 _Color;
			sampler2D _MainTex;
			float4 _MainTex_ST;
			fixed _Cutoff;

			struct a2v{
				float4 vertex : POSITION;
				float3 normal: NORMAL;
				float4 texcoord : TEXCOORD0;
			};

			struct v2f{
				float4 pos : POSITION;
				float3 worldNormal: TEXCOORD0;
				float3 worldPos : TEXCOORD1;
				float2 uv: TEXCOORD2;		
			};

			v2f vert(a2v v){
				v2f o;
				o.pos = UnityViewToClipPos(v.vertex);
				o.worldNormal = UnityObjectToWorldNormal(v.normal);
				o.worldPos = mul(unity_ObjectToWorld,v.vertex).xyz;
				o.uv = TRANSFORM_TEX(v.texcoord,_MainTex);

				return o ;
			}

			fixed4 frag(v2f i):SV_TARGET0{
				// 世界空間法線歸一化
				fixed3 worldNormal = normalize(i.worldNormal);
				// 世界空間光照方向歸一化
				fixed3 worldLightDir = normalize(UnityWorldSpaceLightDir(i.worldPos));
				// 對主紋理進行採樣
				fixed4 texColor = tex2D(_MainTex,i.uv);

				// AlphaTest 如果給定向量或給定標量的任何分量爲負，則終止當前像素輸出
				clip(texColor.a - _Cutoff);
				//反射率，一般就是在光照之前的原始顏色
				fixed3 albedo = texColor.rgb * _Color.rgb;
				// 環境光
				fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz * albedo;
				// 漫反射
				fixed3 diffuse = _LightColor0.rgb * albedo * max(0,dot(worldNormal,worldLightDir));

				return ambient + diffuse;
			}

			ENDCG
		}
	}

	Fallback "Transparent/Cutout/VertexLit"
}