练手之RimLight

简单写写，练下手~

Shader "James/VP Shader/RimLight"

{

    Properties

    {

        _MainTex("MainTex", 2D) = "white" {}

        _Color("Color", Color) = (, , , )

        _RimColor("RimColor", Color) = (, , , )

        _RimPower("RimPower", Range(, )) = 0.1

        _RimIntensity("RimIntensity", Range(, )) =

    }

    SubShader

    {

        Tags { "Queue" = "Transparent" }

        Pass

        {

            ZWrite Off

            Blend SrcAlpha OneMinusSrcAlpha

            CGPROGRAM

            #pragma vertex vert

            #pragma fragment frag

            #include "UnityCG.cginc"

            struct v2f

            {

                float4 pos : SV_POSITION;

                float3 color : COLOR0;

                float2 uv : TEXCOORD0;

                float3 normal : TEXCOORD1;

                float3 objViewDir : TEXCOORD2;

            };

            sampler2D _MainTex;

            float4 _MainTex_ST;

            float4 _Color;

            v2f vert(appdata_base v)

            {

                v2f o;

                o.pos = mul (UNITY_MATRIX_MVP, v.vertex);

                o.normal = v.normal;

                o.objViewDir =  normalize(ObjSpaceViewDir(v.vertex));

                o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);

                return o;

            }

            float4 _RimColor;

            float _RimPower;

            float _RimIntensity;

            half4 frag(v2f i) : COLOR

            {

                float rimSin =  - max(, dot(i.normal, i.objViewDir));

                float rimFactor = pow(rimSin, _RimPower) * _RimIntensity;

                float3 rimColor = rimFactor * _RimColor;

                float4 mainColor = tex2D(_MainTex, i.uv);

                float4 finalColor = mainColor * _Color;

                finalColor.rgb +=rimColor;

                return finalColor;

            }

            ENDCG

        }

    }

    FallBack "VertexLit"

}

　　　将上面的Shader改写一下，添加BumpTex，并使用一张RimTex来映射边缘光的强度：

Shader "James/VP Shader/BumpRimLight"

{

    Properties

    {

        _MainTex("MainTex", 2D) = "white" {}

        _BumpTex("BumpTex", 2D) = "bump" {}

        _Color("Color", Color) = (, , , )

        _RimColor("RimColor", Color) = (, , , )

        _RimIntensity("RimIntensity", Range(, )) = 0.1

        _RimTex("RimTex", 2D) = "white" {}

    }

    SubShader

    {

        Tags { "Queue" = "Transparent" }

        Pass

        {

            Blend SrcAlpha OneMinusSrcAlpha

            CGPROGRAM

            #pragma vertex vert

            #pragma fragment frag

            #include "UnityCG.cginc"

            struct v2f

            {

                float4 pos : SV_POSITION;

                float3 color : COLOR0;

                float2 uv : TEXCOORD0;

                float3 tangentSpackLightDir : TEXCOORD1;

            };

            sampler2D _MainTex;

            sampler2D _BumpTex;

            sampler2D _RimTex;

            float4 _MainTex_ST;

            float4 _BumpTex_ST;

            float4 _RimTex_ST;

            float4 _Color;

            float4 _RimColor;

            float _RimIntensity;

            v2f vert(appdata_tan v)

            {

                v2f o;

                o.pos = mul (UNITY_MATRIX_MVP, v.vertex);

                float3 objViewDir =  normalize(ObjSpaceViewDir(v.vertex));

                o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);

                // 副法向量

                float3 binormal = cross(normalize(v.vertex), normalize(v.tangent.xyz));

                // 切空间矩阵

                float3x3 rotation = float3x3(v.tangent.xyz, binormal, v.normal);

                // 切空间视线方向

                o.tangentSpackLightDir = mul(rotation, objViewDir);

                return o;

            }

            half4 frag(v2f i) : COLOR

            {

                // 切空间法线，NormalMap默认带的是切空间的值

                half3 tangentSpaceNormal = (tex2D(_BumpTex, i.uv).rgb * 2.0) - 1.0;

                float rimFactor =  - max(, dot(tangentSpaceNormal, i.tangentSpackLightDir));

                float rimIntensity = tex2D(_RimTex, rimFactor.xx).r;

                float3 rimColor = rimIntensity * _RimColor  * _RimIntensity;

                float4 mainColor = tex2D(_MainTex, i.uv);

                float4 finalColor = mainColor * _Color;

                finalColor.rgb += rimColor;

                return finalColor;

            }

            ENDCG

        }

    }

    FallBack "VertexLit"

}

　　　注意上述代码是在切空间中计算rim的颜色强度。