高光 + 金属着色器

Question

Unity 标准着色器如何具有“镜面高光”同时又具有“金属”？

我正在尝试做完全相同的事情，但我无法弄清楚。到目前为止，我有：

// Upgrade NOTE: replaced '_World2Object' with 'unity_WorldToObject'
// Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'

Shader "Custom/MetallicHighlights" {
    Properties {
        _Color ("Color", Color) = (1, 1, 1, 1)
        _MainTex ("Albedo", 2D) = "white" {}

        _GlossMapScale ("Smoothness", Range(0.0, 1.0)) = 0.0
        _MetallicFactor("Metallic Factor", Range(0.0, 1.0)) = 0
        _MetallicGlossMap ("Metallic", 2D) = "gloss" {}
    }
    SubShader {
        Tags { "RenderType"="Opaque" }
        LOD 200

        CGPROGRAM
        // Physically based Standard lighting model, and enable shadows on all light types
        // And generate the shadow pass with instancing support
        #pragma surface surf Standard fullforwardshadows addshadow

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

        struct Input {
            float4 color: Color;
            float2 uv_MainTex;
            float3 viewDir;
        };

        sampler2D _MainTex;
        sampler2D _MetallicGlossMap;
        fixed4 _Color;
        half _GlossMapScale;
        half _MetallicFactor;

        void surf (Input IN, inout SurfaceOutputStandard o) {
            // Albedo comes from a texture tinted by color
            fixed4 albedo = tex2D (_MainTex, IN.uv_MainTex) * _Color;
            o.Albedo = albedo.rgb;
            o.Alpha = albedo.a;

            half rim = _RimCap - saturate(dot(normalize(IN.viewDir), o.Normal));
            o.Emission = _RimColor.rgb * pow(rim, _RimIntensity);

            // Metallic and smoothness come from slider variables
            // o.Metallic = _MetallicFactor;
            // o.Smoothness = _GlossMapScale;

            fixed4 metal_colour = tex2D(_MetallicGlossMap, IN.uv_MainTex);
            o.Metallic = metal_colour.r * _MetallicFactor;
            o.Smoothness = metal_colour.a * _GlossMapScale;
        }
        ENDCG
    }
    FallBack "Diffuse"
}

但当我检查 Unity 标准着色器时，我注意到它有“金属”（滑块 + 纹理），还有“高光”（复选框）和“前向渲染选项”的“反射”（复选框）..

他们究竟是如何做到的？如果我使用SurfaceOutputStandardSpecular，那么我会在结构中丢失Metallic 选项。

有什么想法吗？

Answer 1

它应该可以工作：

// Upgrade NOTE: replaced '_World2Object' with 'unity_WorldToObject'
// Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'

Shader "Custom/MetallicHighlights" {
    Properties {
        _Color ("Color", Color) = (1, 1, 1, 1)
        _MainTex ("Albedo", 2D) = "white" {}

        _GlossMapScale ("Smoothness", Range(0.0, 1.0)) = 0.0
        _MetallicFactor("Metallic Factor", Range(0.0, 1.0)) = 0
        _MetallicGlossMap ("Metallic", 2D) = "gloss" {}
        [ToggleOff] _SpecularHighlights("Specular Highlights", Float) = 1.0
    }
    SubShader {
        Tags { "RenderType"="Opaque" }
        LOD 200

        CGPROGRAM
        // Physically based Standard lighting model, and enable shadows on all light types
        // And generate the shadow pass with instancing support
        #pragma surface surf Standard fullforwardshadows addshadow
        #pragma shader_feature _SPECULARHIGHLIGHTS_OFF

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

        struct Input {
            float4 color: Color;
            float2 uv_MainTex;
            float3 viewDir;
        };

        sampler2D _MainTex;
        sampler2D _MetallicGlossMap;
        fixed4 _Color;
        half _GlossMapScale;
        half _MetallicFactor;

        void surf (Input IN, inout SurfaceOutputStandard o) {
            // Albedo comes from a texture tinted by color
            fixed4 albedo = tex2D (_MainTex, IN.uv_MainTex) * _Color;
            o.Albedo = albedo.rgb;
            o.Alpha = albedo.a;

            half rim = _RimCap - saturate(dot(normalize(IN.viewDir), o.Normal));
            o.Emission = _RimColor.rgb * pow(rim, _RimIntensity);

            // Metallic and smoothness come from slider variables
            // o.Metallic = _MetallicFactor;
            // o.Smoothness = _GlossMapScale;

            fixed4 metal_colour = tex2D(_MetallicGlossMap, IN.uv_MainTex);
            o.Metallic = metal_colour.r * _MetallicFactor;
            o.Smoothness = metal_colour.a * _GlossMapScale;
        }
        ENDCG
    }
    FallBack "Diffuse"
}