//Vertex program for bump reflection
void main(
        float4 Position : POSITION, //in object space
        float2 TexCoord : TEXCOORD0,
        float3 T : TEXCOORD1, //in object space
        float3 B : TEXCOORD2, //in object space
        float3 N : TEXCOORD3, //in object space

    out float4 oPosition : POSITION, //in projection space
    out float4 oTexCoord : TEXCOORD0,
    out float4 oTangentToCubeSpace0 : TEXCOORD1, //first row of the 3x3 transform from tangent to cube space
    out float4 oTangentToCubeSpace1 : TEXCOORD2, //second row of the 3x3 transform from tangent to cube space
    out float4 oTangentToCubeSpace2 : TEXCOORD3, //third row of the 3x3 transform from tangent to cube space

        uniform float4x4 WorldViewProj,
        uniform float3x4 ObjToCubeSpace,
        uniform float3 EyePosition, // in cube space
        uniform float BumpScale)
{
    // pass texture coordinates for fetching the normal map
    oTexCoord.xy = TexCoord.xy;

    // compute the 3x3 tranform from tangent space to object space
    float3x3 objToTangentSpace;
    // first rows are the tangent and binormal scaled by the bump scale
    objToTangentSpace[0] = BumpScale * T;
    objToTangentSpace[1] = BumpScale * B;
    objToTangentSpace[2] = N;

    // compute the 3x3 transform from tangent space to cube space:
    // TangentToCubeSpace = object2cube * tangent2object
    //              = object2cube * transpose(objToTangentSpace) (since the inverse of a rotation is its transpose)
    // so a row of TangentToCubeSpace is the transform by objToTangentSpace of the corresponding row of ObjToCubeSpace
    oTangentToCubeSpace0.xyz = mul(objToTangentSpace, ObjToCubeSpace[0].xyz);
    oTangentToCubeSpace1.xyz = mul(objToTangentSpace, ObjToCubeSpace[1].xyz);
    oTangentToCubeSpace2.xyz = mul(objToTangentSpace, ObjToCubeSpace[2].xyz);

    // compute the eye vector (going from shaded point to eye) in cube space
    float3 eyeVector = EyePosition - mul(ObjToCubeSpace, Position);
    oTangentToCubeSpace0.w = eyeVector.x;
    oTangentToCubeSpace1.w = eyeVector.y;
    oTangentToCubeSpace2.w = eyeVector.z;

    // transform position to projection space
    oPosition = mul(WorldViewProj, Position);
}

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//fragment program for bump reflection

void main(
        float4 Position : POSITION, //in projection space
        float4 TexCoord : TEXCOORD0,
        float4 TangentToCubeSpace0 : TEXCOORD1, //first row of the 3x3 transform from tangent to cube space
        float4 TangentToCubeSpace1 : TEXCOORD2, //second row of the 3x3 transform from tangent to cube space
        float4 TangentToCubeSpace2 : TEXCOORD3, //third row of the 3x3 transform from tangent to cube space

        out float4 Color : COLOR,

                uniform sampler2D NormalMap,
                uniform samplerCUBE EnvironmentMap) 
{
    // fetch the bump normal from the normal map
    float4 normal = tex2D(NormalMap);

    // transform the bump normal into cube space
    // then use the transformed normal and eye vector to compute a reflection vector
    // used to fetch the cube map
    // (we multiply by 2 only to increase brightness)
    Color = 2 * texCUBE_reflect_dp3x3(EnvironmentMap, TangentToCubeSpace0, TangentToCubeSpace1, normal);
}