source: data/branches/Shader_HS18/programs/GLSL120/DualQuaternion_TwoPhase.glsl @ 12115

#version 120

mat2x4 blendTwoWeightsAntipod(vec4 blendWgt, vec4 blendIdx, vec4 dualQuaternions[48]);
vec3 calculateBlendPosition(vec3 position, mat2x4 blendDQ);
vec3 calculateBlendNormal(vec3 normal, mat2x4 blendDQ);

mat3 adjointTransposeMatrix(mat3 M)
{
        mat3 atM;
        atM[0][0] = M[2][2] * M[1][1] - M[2][1] * M[1][2];
        atM[1][0] = M[2][1] * M[0][2] - M[0][1] * M[2][2];
        atM[2][0] = M[0][1] * M[1][2] - M[0][2] * M[1][1];

        atM[0][1] = M[2][0] * M[1][2] - M[2][2] * M[1][0];
        atM[1][1] = M[2][2] * M[0][0] - M[2][0] * M[0][2];
        atM[2][1] = M[0][2] * M[1][0] - M[0][0] * M[1][2];

        atM[0][2] = M[2][1] * M[1][0] - M[2][0] * M[1][1];
        atM[1][2] = M[0][1] * M[2][0] - M[2][1] * M[0][0];
        atM[2][2] = M[0][0] * M[1][1] - M[0][1] * M[1][0];

        return atM;
}

uniform vec4 worldDualQuaternion2x4Array[48];
uniform vec4 scaleM[72];
uniform mat4 viewProjectionMatrix;
uniform vec4   lightPos[2];
uniform vec4   lightDiffuseColour[2];
uniform vec4   ambient;

attribute vec4 vertex;
attribute vec3 normal;
attribute vec4 blendIndices;
attribute vec4 blendWeights;
attribute vec4 uv0;

void main()
{       
        //First phase - applies scaling and shearing:
        int blendIndicesX = int(blendIndices.x) * 3;
        int blendIndicesY = int(blendIndices.y) * 3;
        
        mat3x4 blendS = blendWeights.x*mat3x4(scaleM[blendIndicesX], 
                scaleM[blendIndicesX + 1], scaleM[blendIndicesX + 2]);
        
        blendS += blendWeights.y*mat3x4(scaleM[blendIndicesY],                                          scaleM[blendIndicesY + 1], scaleM[blendIndicesY + 2]);

        mat4x3 blendF = transpose(blendS);

        vec3 pass1_position = blendF * vertex;

        mat3x3 blendSrotAT = adjointTransposeMatrix(mat3x3(blendF));
        vec3 pass1_normal = normalize(blendSrotAT * normal);

        //Second phase
        mat2x4 blendDQ = blendTwoWeightsAntipod(blendWeights, blendIndices, worldDualQuaternion2x4Array);

        blendDQ /= length(blendDQ[0]);

        vec3 blendPosition = calculateBlendPosition(pass1_position, blendDQ);

        //No need to normalize, the magnitude of the normal is preserved because only rotation is performed
        vec3 blendNormal = calculateBlendNormal(pass1_normal, blendDQ);
        
        gl_Position =  viewProjectionMatrix * vec4(blendPosition, 1.0);

        // Lighting - support point and directional
        vec3 lightDir0 = normalize(lightPos[0].xyz - (blendPosition * lightPos[0].w));
        vec3 lightDir1 = normalize(lightPos[1].xyz - (blendPosition * lightPos[1].w));

        gl_TexCoord[0] = uv0;

        gl_FrontColor = gl_FrontMaterial.diffuse * (ambient + (clamp(dot(lightDir0, blendNormal), 0.0, 1.0) * lightDiffuseColour[0]) + 
                (clamp(dot(lightDir1, blendNormal), 0.0, 1.0) * lightDiffuseColour[1]));                        
}