[小明学Shader]4.自定义光照----RampTexture

上一篇讲了自定义光照的HalfLambert,这一次和它有些类似,但是计算的时候,不再用方向和atten相乘了.

将光入射方向与法相的点乘积HalfLam作为坐标,找到RampTexture中(HalfLam,HalfLam)点的rgb值作为混合值与s.的Albedo和入射光颜色相乘.

代码如下:

Shader"Custom/11.26/2"{
Properties{
    _RampTex("Ramp Texture",2D)="white"{}
    _MainTex("Ramp Texture",2D)="white"{}
}
SubShader{
    Tags{"RenderType"="Opaque"}
    LOD 200

    CGPROGRAM
    #pragma surface surf Ramp

    sampler2D _RampTex;
    sampler2D _MainTex;

    struct Input{
        float2 uv_MainTex;
    };

    void surf(Input In,inout SurfaceOutput o){
        half4 c=tex2D(_MainTex,In.uv_MainTex);

        o.Albedo=c.rgb;
        o.Alpha=c.a;
    }

    inline float4 LightingRamp(SurfaceOutput s,fixed3 LightDir,fixed atten){
        float lightDif=dot(s.Normal,LightDir);
        float halfLam=0.5*lightDif+0.5;

        float3 ramp=tex2D(_RampTex,float2(halfLam,halfLam)).rgb;

        float4 col;
        col.rgb=s.Albedo*_LightColor0.rgb*ramp;
        col.a=s.Alpha;

        return col;
    }

    ENDCG
}
FallBack "Diffuse"
}

效果图: