source: GTP/trunk/App/Demos/Illum/Ogre/Media/Demo/bump.hlsl @ 2157

uniform float textureRepeat = 6;
uniform sampler2D ColorMapSampler : register(s0);
uniform sampler2D DetailMapSampler   : register(s1);
uniform sampler2D BumpMapSampler  : register(s2);
uniform float4x4 WorldViewProj;
uniform float4x4 World;
uniform float4x4 WorldI;
uniform float4 wLightPos;
uniform float3 wCamPos;


float3x3 TransfModelToTangent( in  float3 Tangent, in float3 Binormal, in float3 Normal ) {
        float T2 = dot(Tangent, Tangent);
        float B2 = dot(Binormal, Binormal);
        float N2 = dot(Normal, Normal);
        float BT = dot(Binormal, Tangent);
        float det = B2 * T2 - BT * BT;

        return float3x3( (B2 * Tangent - BT * Binormal)/det, 
                         (T2 * Binormal - BT * Tangent)/det, 
                         Normal/N2 );
/*                                                      
        // simplified solution
        return float3x3(Tangent/T2, Binormal/B2, Normal/N2); 
*/
}

float4 Illumination(float3 Light, float3 Normal, float3 View, float2 TexCoord, float2 TexCoord2)
{
        // Blinn lighting
        float3 Half = normalize(Light + View);
        float Diffuse = dot(Normal, Light);
        float Specular = dot(Normal, Half);
        float4 Lighting = lit(Diffuse, Specular, 16);
        float4 Color= tex2D(ColorMapSampler, TexCoord) * tex2D(DetailMapSampler, TexCoord2);

        return (Lighting.y + 0.1) * Color;
}

struct VS_INPUT {
    float4 Position  : POSITION;     // point in modeling space
    float2 TexCoord  : TEXCOORD0;    // texture coordinates
    float2 TexCoord2 : TEXCOORD1;    // texture coordinates
    float3 Tangent   : TEXCOORD2;        // model space tangent vector
    float3 Normal    : NORMAL;           // model space triangle normal vector
};

struct VS_OUTPUT {
    float4 hPosition : POSITION;     // point in normalized device space before homogeneous division
    float2 TexCoord  : TEXCOORD0;    // texture coordinates
    float2 TexCoord2  : TEXCOORD6;    // texture coordinates
    float3 mView     : TEXCOORD1;    // model space view vector
    float3 mLight    : TEXCOORD2;    // model space light vector
    float3 wTangent   : TEXCOORD3;       // model space tangent vector
    float3 wBinormal  : TEXCOORD4;       // model space binormal vector
    float3 wNormal    : TEXCOORD5;       // model space triangle normal vector
};




//------------------------------------------------------------------------------------
//
// Base vertex shader: vertex shader for all methods: calculates tangent-space
//              tLight, tView, hPosition vectors
//
//------------------------------------------------------------------------------------
VS_OUTPUT BaseVS(VS_INPUT IN)
{
        VS_OUTPUT OUT;

        float3 wPos = mul(World, IN.Position);
                // world-space view vector        
                OUT.mView = wCamPos - wPos;
                // world-space light vector
                OUT.mLight = wLightPos.xyz - wPos * wLightPos.w;

                OUT.wTangent = normalize(mul(float4(IN.Tangent, 1),WorldI));
                OUT.wNormal = normalize(mul(float4(IN.Normal, 1),WorldI));              
                OUT.wBinormal = cross(OUT.wTangent, OUT.wNormal);               
                
        // vertex position before homogenious division
        OUT.hPosition = mul(WorldViewProj, IN.Position);
                // tex coordinates passed to pixel shader
        OUT.TexCoord = textureRepeat * IN.TexCoord;
        OUT.TexCoord2 = IN.TexCoord2;

                return OUT;
}

float4 BumpPS(VS_OUTPUT IN) : COLOR
{
        //return tex2D(BumpMapSampler,IN.TexCoord).a;
        IN.wTangent = normalize(IN.wTangent);
        IN.wBinormal = normalize(IN.wBinormal);
        IN.wNormal = normalize(IN.wNormal);
        // needs normalization because of linear interpolation    
    float3 mLight = normalize( IN.mLight );
    float3 mView = normalize( IN.mView );
 
    // get model space normal vector
        float3x3 ModelToTangent = TransfModelToTangent(IN.wTangent, IN.wBinormal, IN.wNormal );
    // get model space normal vector
    float3 tNormal = tex2D(BumpMapSampler, IN.TexCoord).rgb;
        // Normal vector should be transformed with the inverse transpose of TangentToModel
        // which is the transpose of ModelToTangent
    float3 mNormal = normalize( mul( tNormal, ModelToTangent ) ); 
        // illumination calculation
    return Illumination(mLight, mNormal, mView, IN.TexCoord, IN.TexCoord2);
    
}