Miscellany

sampler2D Lightmap1 : register(s0);
sampler2D Lightmap2 : register(s1);
sampler2D Lightmap3 : register(s2);
sampler2D weightingtex : register(s3);
sampler2D detail0bump : register(s4);
sampler2D detail1bump : register(s5);
sampler2D detail2bump : register(s6);
sampler2D detail3bump : register(s7);
sampler2D detailbasebump : register(s8);

float2 detail0scale;
float2 detail1scale;
float2 detail2scale;
float2 detail3scale;
float2 detailbasescale;

float detail0distance;
float detail1distance;
float detail2distance;
float detail3distance;
float detailbasedistance;

float4 fSpecValues;
float4 bumpAltNormal;

float4 ComputeDot3LightmapLightingSpec(float3 normal, float3 lightDir, float3 eyeDir, float4 lightContrib, float specExp)
{
  float fDot;
  fDot = max(dot(normal, lightDir) , 0.0);
  return lightContrib * fDot;
}

struct PS_IN
{                  
  float2 UV0 : TEXCOORD0;
  float2 UV2 : TEXCOORD2;
  float3 EyeDir : TEXCOORD3;
  float EyeDist : TEXCOORD4;
  float Depth : TEXCOORD5;
};
   
float4 ps_main( PS_IN In ) : COLOR
{
	const float3 vLightDir1 = float3(0.816497, 0.000000, 0.577350);
	const float3 vLightDir2 = float3(-0.408248, 0.707107, 0.577350);
	const float3 vLightDir3 = float3(-0.408248, -0.707107, 0.577350);

	// sample all lightmaps
	float4 cLightmap1 = tex2D(Lightmap1, In.UV2);
	float4 cLightmap2 = tex2D(Lightmap2, In.UV2);
	float4 cLightmap3 = tex2D(Lightmap3, In.UV2);
  
  	// lookup our weightmaps
    float4 weighting = tex2D(weightingtex, In.UV0);

  	// diffuse color
  	float4 cNormalMap, d0, d1, d2, d3;

  	// lookup basedetail texture
  	if (In.EyeDist < detailbasedistance) {
    	cNormalMap = tex2D(detailbasebump,In.UV0 * detailbasescale);    
    }

    // lookup detailtextures and mix the color
    if (In.EyeDist < detail0distance) {
    	d0 = tex2D(detail0bump, In.UV0 * detail0scale);
  		cNormalMap = lerp(cNormalMap, d0, weighting.a);
  	}
  	if (In.EyeDist < detail1distance) {
  		d1 = tex2D(detail1bump, In.UV0 * detail1scale);
  		cNormalMap = lerp(cNormalMap, d1, weighting.r);
  	}
  	if (In.EyeDist < detail2distance) {
  		d2 = tex2D(detail2bump, In.UV0 * detail2scale);
  		cNormalMap = lerp(cNormalMap, d2, weighting.g);
  	}
  	if (In.EyeDist < detail3distance) {
  		d3 = tex2D(detail3bump, In.UV0 * detail3scale);
  		cNormalMap = lerp(cNormalMap, d3, weighting.b);
  	}

  	if (In.EyeDist < detailbasedistance || In.EyeDist < detail0distance || In.EyeDist < detail1distance
  	    || In.EyeDist < detail2distance || In.EyeDist < detail3distance) {
		cNormalMap.xyz = normalize(cNormalMap.xyz * 2.0f - float3(1.0f, 1.0f, 1.0f));
	} else {
		cNormalMap.xyz = bumpAltNormal;
	}
	
	// eye direction vector
	float3 vEyeNorm = normalize(In.EyeDir);
	float4 vAccum;
  
	vAccum  = ComputeDot3LightmapLightingSpec(cNormalMap.xyz, vLightDir1, vEyeNorm, cLightmap1, fSpecValues.y);
	vAccum += ComputeDot3LightmapLightingSpec(cNormalMap.xyz, vLightDir2, vEyeNorm, cLightmap2, fSpecValues.y);
	vAccum += ComputeDot3LightmapLightingSpec(cNormalMap.xyz, vLightDir3, vEyeNorm, cLightmap3, fSpecValues.y);
		
	return In.Depth * vAccum;
}