逐顶点和逐像素的高光模型

• 左为逐顶点高光Phong模型
• 中为逐像素高光Phong模型
• 右为逐像素高光Blinn-Phong模型
• Phong模型$$C{specular=(c{light}*m{specular})max(0, \vec{v}·\vec{r})^{m{Gloss}}}$$
• Blinn-Phong模型$$C{specular=(c{light}*m{specular})max(0, \vec{n}·\vec{h})^{m{Gloss}}}$$
  • $$\vec{h} = \frac{\vec{v}·\vec{i}}{|v||i|}$$

Shader "UnityShaderLearning/SpecularVertexLevel"
{
    Properties
    {
        _Diffuse("Diffuse", Color) = (1, 1, 1, 1)
        _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 _Diffuse;
            fixed4 _Specular;
            float _Gloss;

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

            struct v2f
            {
                float4 pos : SV_POSITION;
                float3 color : COLOR;
            };

            v2f vert(a2v v)
            {
                v2f o;
                o.pos = mul(UNITY_MATRIX_MVP, v.vertex);

                fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz;
                fixed3 worldNormal = normalize(mul(v.normal, (float3x3)_World2Object));
                fixed3 worldLightDir = normalize(_WorldSpaceLightPos0.xyz);
                fixed3 diffuse = _LightColor0.rgb * _Diffuse.rgb * saturate(dot(worldNormal, worldLightDir));

                fixed3 reflectDir = normalize(reflect(-worldLightDir, worldNormal));
                fixed3 viewDir = normalize(_WorldSpaceCameraPos.xyz - mul(_Object2World, v.vertex).xyz);
                fixed3 specular = _LightColor0.rgb * _Specular.rgb * pow(saturate(dot(reflectDir, viewDir)), _Gloss);

                o.color = ambient + diffuse + specular;
                return o;
            }

            fixed4 frag(v2f i) :SV_Target
            {
                return fixed4(i.color, 1.0);
            }

            ENDCG
        }
    }
    FallBack "Specular"
}

Shader "UnityShaderLearning/SpecularPixelLevel"
{
    Properties
    {
        _Diffuse("Diffuse", Color) = (1, 1, 1, 1)
        _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 _Diffuse;
            fixed4 _Specular;
            float _Gloss;

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

            struct v2f
            {
                float4 pos : SV_POSITION;
                float3 worldNormal : TEXCOORD0;
                float3 worldPos : TEXCOORD1;
            };

            v2f vert(a2v v)
            {
                v2f o;
                o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
                o.worldNormal = normalize(mul(v.normal, (float3x3)_World2Object));
                o.worldPos = mul(_Object2World, v.vertex).xyz;
                return o;
            }

            fixed4 frag(v2f i) :SV_Target
            {
                fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz;
                fixed3 worldNormal = normalize(i.worldNormal);
                fixed3 worldLightDir = normalize(_WorldSpaceLightPos0.xyz);
                fixed3 diffuse = _LightColor0.rgb * _Diffuse.rgb * saturate(dot(worldNormal, worldLightDir));

                fixed3 reflectDir = normalize(reflect(-worldLightDir, worldNormal));
                fixed3 viewDir = normalize(_WorldSpaceCameraPos.xyz - i.worldPos.xyz);
                fixed3 specular = _LightColor0.rgb * _Specular.rgb * pow(saturate(dot(reflectDir, viewDir)), _Gloss);

                fixed3 color = ambient + diffuse + specular;
                return fixed4(color, 1.0);
            }

            ENDCG
        }
    }
    FallBack "Specular"
}
```  

```  
fixed3 halfDir = normalize(viewDir + worldLightDir);
fixed3 specular = _LightColor0.rgb * _Specular.rgb * pow(saturate(dot(worldNormal, halfDir)), _Gloss);

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