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标题: 高级光照模型 Cook-Torrance [打印本页]

作者: 会飞的鱼 时间: 2012-2-24 14:16
标题: 高级光照模型 Cook-Torrance
//这个shader 实现 Cook_Torrance 高级光照模型
// powered by sbin3776
shader "Sbin/Cook-Torrance"
{
properties{
  _Color ("Main Color", Color) = (1,1,1,1)
  _MainTex ("Base (RGB) Gloss (A)", 2D) = "white" {}
  _BumpMap ("Normalmap", 2D) = "bump" {}
  _Fo("F0",range(0,1))=0.3
  _Dm("Dm",range(0,1))=0.3
  _ISpecular("ISpecular",range(0,0.3))=0.03
}

subshader
{
  tags{"rendertype"="opaque"}
  CGPROGRAM
  #pragma surface surf Cook_Torrance
  #pragma target 3.0
  sampler2D _MainTex;
  sampler2D _BumpMap;
  fixed4 _Color;
  float _Fo;
  float _Dm;
  float _ISpecular;

  half4 LightingCook_Torrance(SurfaceOutput s, fixed3 lightDir, fixed3 viewDir, fixed atten)
  {
//calculate diffuse color
float kd= saturate(dot( normalize(s.Normal),normalize(lightDir)));
float4 diffuseColor;
diffuseColor.rgb= kd  * s.Albedo * _LightColor0*  (atten *2);
diffuseColor.a=1;

//calculate specular color use Cook-Torrance lighting Model
float3 V= normalize(viewDir);
float3 L= normalize(lightDir);
float3 N= normalize(s.Normal);
float3 H= V+L;
float Ks= saturate(dot(H,N));
float F= _Fo+(1-_Fo)*(pow(1-dot(V,H),5));
float P=pow(Ks,2);
float powDm=_Dm*_Dm;
float NdotH=Ks;
float VdotH=saturate(dot(V,H));
float D= ( 1.0f/( powDm* pow(NdotH,4)) ) * exp( (P-1)/ ( powDm * P) );
float G1=( NdotH * saturate(dot(N,L)) *2 ) /  VdotH;
float G2 = ( NdotH * saturate(dot(N,V)) *2 ) /  VdotH;
float G= min(min(1,G1),G2);
      float4 cook_Torrance_Color= _LightColor0* ( F*D*G / (dot(N,V)* dot(N,L)) ) * _ISpecular * saturate(dot(N,L))* atten;
half4 c;
c= diffuseColor + cook_Torrance_Color ;
c.a= 1;
return c;
}
struct Input {
float2 uv_MainTex;
float2 uv_BumpMap;
  };
  void surf(Input IN,inout SurfaceOutput o)
  {
fixed4 tex = tex2D(_MainTex, IN.uv_MainTex);
o.Albedo = _Color.rgb * tex.rgb ;
o.Gloss = tex.a;
o.Alpha = tex.a * _Color.a;
o.Normal = UnpackNormal(tex2D(_BumpMap, IN.uv_BumpMap));
  }

  ENDCG
}
Fallback "Diffuse"
}

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