如何将单独的凹凸贴图添加到此splat贴图着色器（Unity3D）中的每个通道？

我在Unity3D中有一个用于splat贴图的着色器。这是一个弗兰肯斯坦怪兽，来自几个不同的怪兽，我发现我终于开始工作了。问题是它不能在纹理上进行凹凸贴图

Shader "Custom/Texture Splatting" {

Properties {
    _MainTex ("Splat Map", 2D) = "white" {}
    [NoScaleOffset] _Texture1 ("R", 2D) = "white" {}
    [NoScaleOffset] _Texture2 ("G", 2D) = "white" {}
    [NoScaleOffset] _Texture3 ("B", 2D) = "white" {}
    [NoScaleOffset] _Texture4 ("A", 2D) = "white" {}
    _BumpMap1 ("BumpMapR", 2D) = "bump" {}
    _BumpMap2 ("BumpMapG", 2D) = "bump" {}
    _BumpMap3 ("BumpMapB", 2D) = "bump" {}
    _BumpMap4 ("BumpMapA", 2D) = "bump" {}
}

SubShader {

    Pass {
        CGPROGRAM

        #pragma vertex MyVertexProgram
        #pragma fragment MyFragmentProgram

        #include "UnityCG.cginc"

        sampler2D _MainTex;
        float4 _MainTex_ST;

        sampler2D _Texture1, _Texture2, _Texture3, _Texture4;

        struct VertexData {
            float4 position : POSITION;
            float2 uv : TEXCOORD0;
        };

        struct Interpolators {
            float4 position : SV_POSITION;
            float2 uv : TEXCOORD0;
            float2 uvSplat : TEXCOORD1;
        };

        Interpolators MyVertexProgram (VertexData v) {
            Interpolators i;
            i.position = UnityObjectToClipPos(v.position);
            i.uv = TRANSFORM_TEX(v.uv, _MainTex);
            i.uvSplat = v.uv;
            return i;
        }

        float4 MyFragmentProgram (Interpolators i) : SV_TARGET {
            float4 splat = tex2D(_MainTex, i.uvSplat);

            return
                tex2D(_Texture1, i.uv) * splat.r +
                tex2D(_Texture2, i.uv) * splat.g +
                tex2D(_Texture3, i.uv) * splat.b +
                tex2D(_Texture4, i.uv) * (1 - splat.r - splat.g - splat.b);
        }

        ENDCG
    }
}

如果有人能向我展示如何更改/添加此着色器代码，使其能够为每个RGBA通道纹理提供单独的凹凸贴图，我将不胜感激

Shader "Custom/Texture Splatting" {

Properties {
    _MainTex ("Splat Map", 2D) = "white" {}
    [NoScaleOffset] _Texture1 ("R", 2D) = "white" {}
    [NoScaleOffset] _Texture2 ("G", 2D) = "white" {}
    [NoScaleOffset] _Texture3 ("B", 2D) = "white" {}
    [NoScaleOffset] _Texture4 ("A", 2D) = "white" {}
    _BumpMap1 ("BumpMapR", 2D) = "bump" {}
    _BumpMap2 ("BumpMapG", 2D) = "bump" {}
    _BumpMap3 ("BumpMapB", 2D) = "bump" {}
    _BumpMap4 ("BumpMapA", 2D) = "bump" {}
}

SubShader {

    Pass {
        CGPROGRAM

        #pragma vertex MyVertexProgram
        #pragma fragment MyFragmentProgram

        #include "UnityCG.cginc"

        sampler2D _MainTex;
        float4 _MainTex_ST;

        sampler2D _Texture1, _Texture2, _Texture3, _Texture4;

        struct VertexData {
            float4 position : POSITION;
            float2 uv : TEXCOORD0;
        };

        struct Interpolators {
            float4 position : SV_POSITION;
            float2 uv : TEXCOORD0;
            float2 uvSplat : TEXCOORD1;
        };

        Interpolators MyVertexProgram (VertexData v) {
            Interpolators i;
            i.position = UnityObjectToClipPos(v.position);
            i.uv = TRANSFORM_TEX(v.uv, _MainTex);
            i.uvSplat = v.uv;
            return i;
        }

        float4 MyFragmentProgram (Interpolators i) : SV_TARGET {
            float4 splat = tex2D(_MainTex, i.uvSplat);

            return
                tex2D(_Texture1, i.uv) * splat.r +
                tex2D(_Texture2, i.uv) * splat.g +
                tex2D(_Texture3, i.uv) * splat.b +
                tex2D(_Texture4, i.uv) * (1 - splat.r - splat.g - splat.b);
        }

        ENDCG
    }
}

---

}

凹凸贴图通常用于影响曲面上的照明行为，增加曲面不是平面的印象。但是，上面的示例是一个未照明的顶点着色器，它没有任何照明模拟，因此不能只添加凹凸贴图，首先需要将着色器转换为照明着色器。我建议改为使用曲面着色器

如果您仍然想使用顶点着色器进行照明，这是一个完全不同的研究。你可以从中看到一些解释，但除非你真的需要：

也就是说，我制作了一个splat曲面着色器，它使用splat贴图混合两种纹理，并包含一个凹凸贴图。我建议您根据需要调整它（使用4个通道而不是2个通道），而不是尝试从头构建一个照明着色器

Shader "Custom/TerrainTwoTexturesBlend" {
    Properties {
        _Color("Tint", Color) = (0.5, 0.5, 0.5, 1)
        _MainTex("Albedo", 2D) = "white" {}
        _BumpMap("Normal Map", 2D) = "bump" {}

        _MainTex2("Albedo 2", 2D) = "white" {}
        _BumpMap2("Normal Map 2", 2D) = "bump" {}

        _Mask("Mask", 2D) = "white" {}

        _Glossiness ("Smoothness", Range(0,1)) = 0.5
        _Specular ("Specular", Range(0,1)) = 0.0
    }

    SubShader {
        Tags { 
            "Queue" = "Geometry-4"
            "RenderType" = "Opaque" 
            "PreviewType" = "Plane" 
            "ForceNoShadowCasting" = "True"
        }
        LOD 200

        ZWrite Off

        CGPROGRAM
        // Physically based Standard lighting model, and enable shadows on all light types
        #pragma surface surf StandardSpecular

        // Use shader model 3.0 target, to get nicer looking lighting
        #pragma target 3.0

        sampler2D _MainTex;
        sampler2D _BumpMap;

        sampler2D _MainTex2;
        sampler2D _BumpMap2;

        sampler2D _Mask;

        struct Input {
            float2 uv_MainTex: TEXCOORD0;
            float2 uv2_MainTex2: TEXCOORD2;
            float2 uv3_Mask: TEXCOORD1;
        };

        half _Glossiness;
        half _Specular;
        fixed4 _Color;

        // Add instancing support for this shader. You need to check 'Enable Instancing' on materials that use the shader.
        // See https://docs.unity3d.com/Manual/GPUInstancing.html for more information about instancing.
        // #pragma instancing_options assumeuniformscaling
        UNITY_INSTANCING_BUFFER_START(Props)
            // put more per-instance properties here
        UNITY_INSTANCING_BUFFER_END(Props)

        void surf (Input IN, inout SurfaceOutputStandardSpecular o) {
            float2 uvterrain1 = IN.uv_MainTex;
            float2 uvterrain2 = IN.uv2_MainTex2;
            float2 uvmask = IN.uv3_Mask;

            fixed4 c1 = tex2D(_MainTex, uvterrain1);
            fixed4 n1 = tex2D(_BumpMap, uvterrain1);

            fixed4 c2 = tex2D(_MainTex2, uvterrain2);
            fixed4 n2 = tex2D(_BumpMap2, uvterrain2);

            fixed4 m = tex2D(_Mask, uvmask);

            o.Albedo = _Color * (c1 * m.r + c2 * (1 - m.r));

            float3 fn1 = UnpackScaleNormal(n1, _BumpScale);
            float3 fn2 = UnpackScaleNormal(n2, _BumpScale2);
            o.Normal = fn1 * m.r + fn2 * (1 - m.r);

            // Metallic and smoothness come from slider variables
            o.Specular = _Specular;
            o.Smoothness = _Glossiness;
            o.Alpha = 1;
        }
        ENDCG
    }
    FallBack "Diffuse"
}

---

非常感谢你！我来试试这个。