地形混合shader

1.四个贴图混合

Shader "Custom/BlendTex_surface" {
    Properties {
        _RTexture("Red Channel Texture", 2D) = "" {}
        _GTexture("Green Channel Texture", 2D) = "" {}
        _BTexture("Blue Channel Texture", 2D) = "" {}
        _ATexture("Alpha Channel Texture", 2D) = "" {}
        _Mask("Mask(RG)",2D) = ""{}
    }
    SubShader {
        Tags { "RenderType"="Opaque" }
        LOD 200
        
        CGPROGRAM
        #pragma surface surf Lambert
        #pragma target 4.0

        sampler2D _RTexture;
        sampler2D _GTexture;
        sampler2D _BTexture;
        sampler2D _ATexture;

        sampler2D _Mask;

        struct Input {
            float2 uv_RTexture;
            float2 uv_GTexture;
            float2 uv_BTexture;
            float2 uv_ATexture;
            float2 uv_Mask;
        };

        void surf (Input IN, inout SurfaceOutput o) {
            float4 rTexData = tex2D(_RTexture, IN.uv_RTexture);
            float4 gTexData = tex2D(_GTexture, IN.uv_GTexture);
            float4 bTexData = tex2D(_BTexture, IN.uv_BTexture);
            float4 aTexData = tex2D(_ATexture, IN.uv_ATexture);
            float4 blendData = tex2D(_Mask, IN.uv_Mask);

            float4 finalColor;
            //根据blendData.g 将 RTexture 和 GTexture 混合
            finalColor = lerp(rTexData, gTexData, blendData.g);//原本为g
            //根据blendData.b 将 BTexture 混合
            finalColor = lerp(finalColor, bTexData, blendData.b);//原本为b
            //根据blendData.a 将 ATexture 混合
            finalColor = lerp(finalColor, aTexData , blendData.a);//原本为a
            finalColor = saturate(finalColor);
            o.Albedo = finalColor.rgb;
            o.Alpha = finalColor.a;
        }
        ENDCG
    } 
    FallBack "Diffuse"
}

Shader "Custom/BlendTex_vertfrag" 
{
Properties 
{
    Tex0 ("Layer 0 (R)", 2D) = "white" {}
    Tex1 ("Layer 1 (G)", 2D) = "white" {}
    Tex2 ("Layer 2 (G)", 2D) = "white" {}
    Tex3 ("Layer 3 (A)", 2D) = "white" {}
    _Control ("Control (RGBA)", 2D) = "red" {}
    _IllumFactor ("Illumin Factor", Range(1,2)) = 1
}
    
SubShader 
{
    Tags{ "Queue" = "Geometry+110"   }
    Pass 
    {
            
        Tags{"LightMode" = "ForwardBase" }

        CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #pragma target 2.0
            #include "UnityCG.cginc"

            sampler2D _Control;
            sampler2D Tex0;
            sampler2D Tex1;
            sampler2D Tex2;
            sampler2D Tex3; 
            half _IllumFactor;

            half4 Tex0_ST;
            half4 Tex1_ST;
            half4 Tex2_ST;
            half4 Tex3_ST;
            half4 _Control_ST;


            struct v2f
            {
                float4    pos : SV_POSITION;
                half2  uv_Tex0:TEXCOORD0;
                half2  uv_Tex1:TEXCOORD1;
                half2  uv_Tex2:TEXCOORD2;
                half2  uv_Tex3:TEXCOORD3;
                half2  uv_Control:TEXCOORD4;
            }; 
            
            struct appdata
            {
                float4 vertex : POSITION;
                float4 texcoord : TEXCOORD0;
            };


            v2f vert (appdata v)
            {
                float4 worldPos = mul(unity_ObjectToWorld, v.vertex);

                v2f o;
            
                o.uv_Control = v.texcoord.xy;
                o.uv_Tex0 = TRANSFORM_TEX(v.texcoord ,Tex0);
                o.uv_Tex1 = TRANSFORM_TEX(v.texcoord ,Tex1);
                o.uv_Tex2 = TRANSFORM_TEX(v.texcoord, Tex2);
                o.uv_Tex3 = TRANSFORM_TEX(v.texcoord, Tex3);
                o.pos =  mul(UNITY_MATRIX_MVP, float4(v.vertex.xyz, 1));

                return o;
            }
                

            fixed4 frag(v2f i) : COLOR
            {
                fixed4 splat_control = tex2D (_Control, i.uv_Control.xy);
            
                fixed4 albedo = fixed4(1,1,1,1);
                fixed4 Tex0Color = tex2D(Tex0, i.uv_Tex0);
                //albedo.rgb  = splat_control.r * Tex0Color.rgb;...用这个会出现不明黑色阴影
                fixed4 Tex1Color = tex2D(Tex1, i.uv_Tex1);
                //albedo.rgb += splat_control.g * Tex1Color.rgb;

                fixed4 Tex2Color = tex2D(Tex2, i.uv_Tex2).rgba;
                //albedo.rgb += splat_control.b * Tex2Color;
                fixed4 Tex3Color = tex2D(Tex3, i.uv_Tex3).rgba;
                //albedo.rgb += splat_control.a * Tex3Color;
                
                albedo = lerp(Tex0Color,Tex1Color, splat_control.g);
                albedo = lerp(albedo,Tex2Color, splat_control.b);
                albedo = lerp(albedo,Tex3Color, splat_control.a);

                return albedo* _IllumFactor;
            }

        ENDCG
    }    
}
    FallBack "Diffuse"
}

2.四个贴图（加法线）混合

Shader "Custom/BlendNormalTex_surface" {
    Properties {
        _RTexture("Red Channel Texture", 2D) = "" {}
        _GTexture("Green Channel Texture", 2D) = "" {}
        _BTexture("Blue Channel Texture", 2D) = "" {}
        _ATexture("Alpha Channel Texture", 2D) = "" {}

        _RNormalTex ("RNormal Map", 2D) = "bump" {}
        _GNormalTex ("GNormal Map", 2D) = "bump" {}
        _BNormalTex ("BNormal Map", 2D) = "bump" {}
        _ANormalTex ("ANormal Map", 2D) = "bump" {}

        _RNormalIntensity ("RNormal Map Intensity", Range(-1,1)) = 1
        _GNormalIntensity ("GNormal Map Intensity", Range(-1,1)) = 1
        _BNormalIntensity ("BNormal Map Intensity", Range(-1,1)) = 1
        _ANormalIntensity ("ANormal Map Intensity", Range(-1,1)) = 1
        _IllumFactor ("Illumin Factor", Range(1,2)) = 1
        
        
        
        _Mask("Mask(RG)",2D) = ""{}
    }
    SubShader {
        Tags { "RenderType"="Opaque" }
        LOD 200
        
        CGPROGRAM
        #pragma surface surf Lambert
        // #pragma surface surf Lambert vertex:vert
        #pragma target 4.0

        sampler2D _RTexture,_GTexture,_BTexture,_ATexture;
        sampler2D _RNormalTex,_GNormalTex,_BNormalTex,_ANormalTex;
        float _RNormalIntensity,_GNormalIntensity,_BNormalIntensity,_ANormalIntensity;
        float _IllumFactor;

        sampler2D _Mask;

        struct Input {
            float2 uv_RTexture;
            float2 uv_GTexture;
            float2 uv_BTexture;
            float2 uv_ATexture;
            float2 uv_RNormalTex;
            float2 uv_GNormalTex;
            float2 uv_BNormalTex;
            float2 uv_ANormalTex;
            float2 uv_Mask;
        //    float3 m_normal;
        };
        void surf (Input IN, inout SurfaceOutput o) {
            float4 rTexData = tex2D(_RTexture, IN.uv_RTexture);
            float4 gTexData = tex2D(_GTexture, IN.uv_GTexture);
            float4 bTexData = tex2D(_BTexture, IN.uv_BTexture);
            float4 aTexData = tex2D(_ATexture, IN.uv_ATexture);
            float4 blendData = tex2D(_Mask, IN.uv_Mask);

            float4 finalColor;
            //根据blendData.g 将 RTexture 和 GTexture 混合
            finalColor = lerp(rTexData, gTexData, blendData.g);
            //根据blendData.b 将 BTexture 混合
            finalColor = lerp(finalColor, bTexData, blendData.b);
            //根据blendData.a 将 ATexture 混合
            finalColor = lerp(finalColor, aTexData , blendData.a);
            finalColor = saturate(finalColor);


            float3 rNormalMap = UnpackNormal(tex2D(_RNormalTex, IN.uv_RNormalTex));
            rNormalMap.xy*=_RNormalIntensity;
            float3 gNormalMap = UnpackNormal(tex2D(_GNormalTex, IN.uv_GNormalTex));
            gNormalMap.xy*=_GNormalIntensity;
            float3 bNormalMap = UnpackNormal(tex2D(_BNormalTex, IN.uv_BNormalTex));
            bNormalMap.xy*=_BNormalIntensity;
            //bNormalMap.z=sqrt(1.0-saturate(dot(bNormalMap.xy,bNormalMap.xy)));这个似乎并没有效果
            float3 aNormalMap = UnpackNormal(tex2D(_ANormalTex, IN.uv_ANormalTex));
            aNormalMap.xy*=_ANormalIntensity;

            float3 finalNormal;
            //根据blendData.g 将 RTexture 和 GTexture 混合
            finalNormal = lerp(rNormalMap, gNormalMap, blendData.g);
            //根据blendData.b 将 BTexture 混合
            finalNormal = lerp(finalNormal, bNormalMap, blendData.b);
            //根据blendData.a 将 ATexture 混合
            finalNormal = lerp(finalNormal, aNormalMap , blendData.a);

            o.Albedo =finalColor*_IllumFactor;
            o.Alpha = finalColor.a;
            o.Normal=finalNormal;
            //o.Normal=rNormalMap*blendData.r+gNormalMap*blendData.g+bNormalMap*blendData.b+aNormalMap*blendData.a;
        }
        ENDCG
    } 
    FallBack "Diffuse"
}

Shader "Custom/BlendNormalTex_vertfrag" 
{
Properties 
{
    Tex0 ("Layer 0 (R)", 2D) = "white" {}
    Tex1 ("Layer 1 (G)", 2D) = "white" {}
    Tex2 ("Layer 2 (G)", 2D) = "white" {}
    Tex3 ("Layer 3 (A)", 2D) = "white" {}

    _Normal0("Normal 0 (A)", 2D) = "bump" {}
    _Normal1("Normal 1 (B)", 2D) = "bump" {}
    _Normal2("Normal 2 (G)", 2D) = "bump" {}
    _Normal3("Normal 3 (R)", 2D) = "bump" {}

    _BumpScale0("BumpScale 0", Range(-1.0,1.0)) = 1.0
    _BumpScale1("BumpScale 1", Range(-1.0, 1.0)) = 1.0
    _BumpScale2("BumpScale 2", Range(-1.0, 1.0)) = 1.0
    _BumpScale3("BumpScale 3", Range(-1.0, 1.0)) = 1.0
    _Control ("Control (RGBA)", 2D) = "red" {}
    _IllumFactor ("Illumin Factor", Range(1,2)) = 1
}
    
SubShader 
{
    Tags{ "Queue" = "Geometry+110"   }
    Pass 
    {
            
        Tags{"LightMode" = "ForwardBase" }

        CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #pragma target 2.0
            #include "UnityCG.cginc"
            #include "Lighting.cginc"

            sampler2D _Control;
            //贴图及纹理
            sampler2D Tex0,Tex1,Tex2,Tex3;
            half4 Tex0_ST,Tex1_ST,Tex2_ST,Tex3_ST;
            //法线贴图及纹理
            sampler2D _Normal0,_Normal1,_Normal2,_Normal3;
            half4 _Normal0_ST,_Normal1_ST,_Normal2_ST,_Normal3_ST;
            half _BumpScale0, _BumpScale1, _BumpScale2, _BumpScale3;

            half _IllumFactor;
            half4 _Control_ST;


            struct v2f
            {
                float4    pos : SV_POSITION;
                float3 normal:NORMAL;
                float4 tangnent:TANGENT;
                half4  uv_Tex0:TEXCOORD0;
                half4  uv_Tex1:TEXCOORD1;
                half4  uv_Tex2:TEXCOORD2;
                half4  uv_Tex3:TEXCOORD3;
                half2  uv_Control:TEXCOORD4;
                half3 lightDir:TEXCOORD5;
                half3 viewDir:TEXCOORD6;
            }; 
            
            struct appdata
            {
                float4 vertex : POSITION;
                float4 texcoord : TEXCOORD0;
                float4 tangent:TANGENT;
                float3 normal:NORMAL;
            };


            v2f vert (appdata v)
            {
                v2f o;
                o.pos =  mul(UNITY_MATRIX_MVP, v.vertex);
                o.uv_Control = v.texcoord.xy;
                o.uv_Tex0.xy = TRANSFORM_TEX(v.texcoord ,Tex0);
                o.uv_Tex0.zw = TRANSFORM_TEX(v.texcoord ,_Normal0);

                o.uv_Tex1.xy = TRANSFORM_TEX(v.texcoord ,Tex1);
                o.uv_Tex1.zw = TRANSFORM_TEX(v.texcoord ,_Normal1);

                o.uv_Tex2.xy = TRANSFORM_TEX(v.texcoord, Tex2);
                o.uv_Tex2.zw = TRANSFORM_TEX(v.texcoord ,_Normal2);
                
                o.uv_Tex3.xy = TRANSFORM_TEX(v.texcoord, Tex3);
                o.uv_Tex3.zw = TRANSFORM_TEX(v.texcoord ,_Normal3);

                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);//暂时没用到,用于补充高光


                fixed4 splat_control = tex2D (_Control, i.uv_Control.xy);


                fixed3 tangentNormal0=UnpackNormal(tex2D(_Normal0, i.uv_Tex0.zw));
                tangentNormal0.xy*=_BumpScale0;

                fixed3 tangentNormal1=UnpackNormal(tex2D(_Normal1, i.uv_Tex1.zw));
                tangentNormal1.xy*=_BumpScale1;

                  fixed3 tangentNormal2=UnpackNormal(tex2D(_Normal2, i.uv_Tex2.zw));
                tangentNormal2.xy*=_BumpScale2;

                  fixed3 tangentNormal3=UnpackNormal(tex2D(_Normal3, i.uv_Tex3.zw));
                tangentNormal3.xy*=_BumpScale3;

                fixed4 albedo = 0.0f;

                fixed4 Tex0Color = tex2D(Tex0, i.uv_Tex0);
                fixed4 Tex1Color = tex2D(Tex1, i.uv_Tex1);
                fixed4 Tex2Color = tex2D(Tex2, i.uv_Tex2);
                fixed4 Tex3Color = tex2D(Tex3, i.uv_Tex3);

                albedo = lerp(Tex0Color*max(0, dot(tangentNormal1, tangentLightDir)),Tex1Color*max(0, dot(tangentNormal1, tangentLightDir)), splat_control.g);
                albedo = lerp(albedo,Tex2Color*max(0, dot(tangentNormal2, tangentLightDir)), splat_control.b);
                albedo = lerp(albedo,Tex3Color*max(0, dot(tangentNormal3, tangentLightDir)), splat_control.a);

                return albedo*_IllumFactor;
            }
        ENDCG
    }    
}
FallBack "Diffuse"
}

效果：

albedo = lerp(Tex0Color,Tex1Color, splat_control.g);

//splat_control.g*Tex0Color+(1-splat_control.g)*Tex1Color 

工程文件：http://files.cnblogs.com/files/luxishi/BlendShader.rar