遮罩纹理
用来保护某些区域避免被修改
原理:使用其中的通道与原图相乘,如果通道值为0,则不受影响。
比如说想要控制高光,就制作一张高光的遮罩图,通过与原图相乘,来控制该遮罩图在原图上的影响大小,用来调出想要的高光。
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Shader "Unity Shaders Book/Chapter 7/Mask Texture" { Properties { _Color ("Color Tint", Color) = (1, 1, 1, 1) _MainTex ("Main Tex", 2D) = "white" {} _BumpMap ("Normal Map", 2D) = "bump" {} _BumpScale("Bump Scale", Float) = 1.0 _SpecularMask ("Specular Mask", 2D) = "white" {} _SpecularScale ("Specular Scale", Float) = 1.0 _Specular ("Specular", Color) = (1, 1, 1, 1) _Gloss ("Gloss", Range(8.0, 256)) = 20 } SubShader { Pass { Tags { "LightMode"="ForwardBase" } CGPROGRAM #pragma vertex vert #pragma fragment frag #include "Lighting.cginc" fixed4 _Color; sampler2D _MainTex; float4 _MainTex_ST; sampler2D _BumpMap; float _BumpScale; sampler2D _SpecularMask; float _SpecularScale; fixed4 _Specular; float _Gloss; struct a2v { float4 vertex : POSITION; float3 normal : NORMAL; float4 tangent : TANGENT; float4 texcoord : TEXCOORD0; }; struct v2f { float4 pos : SV_POSITION; float2 uv : TEXCOORD0; float3 lightDir: TEXCOORD1; float3 viewDir : TEXCOORD2; }; v2f vert(a2v v) { v2f o; o.pos = UnityObjectToClipPos(v.vertex); o.uv.xy = v.texcoord.xy * _MainTex_ST.xy + _MainTex_ST.zw; TANGENT_SPACE_ROTATION; o.lightDir = mul(rotation, ObjSpaceLightDir(v.vertex)).xyz; o.viewDir = mul(rotation, ObjSpaceViewDir(v.vertex)).xyz; return o; } fixed4 frag(v2f i) : SV_Target { fixed3 tangentLightDir = normalize(i.lightDir); fixed3 tangentViewDir = normalize(i.viewDir);
fixed3 tangentNormal = UnpackNormal(tex2D(_BumpMap, i.uv)); tangentNormal.xy *= _BumpScale; tangentNormal.z = sqrt(1.0 - saturate(dot(tangentNormal.xy, tangentNormal.xy)));
fixed3 albedo = tex2D(_MainTex, i.uv).rgb * _Color.rgb; fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz * albedo; fixed3 diffuse = _LightColor0.rgb * albedo * max(0, dot(tangentNormal, tangentLightDir)); fixed3 halfDir = normalize(tangentLightDir + tangentViewDir); fixed specularMask = tex2D(_SpecularMask, i.uv).r * _SpecularScale; fixed3 specular = _LightColor0.rgb * _Specular.rgb * pow(max(0, dot(tangentNormal, halfDir)), _Gloss) * specularMask; return fixed4(ambient + diffuse + specular, 1.0); } ENDCG } } FallBack "Specular" }
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重复利用遮罩:把不同属性存储在图片不同通道中,已到达更好的效果。