int GLUtility::unProject(float winx, float winy, float winz, float *modelview, float *projection, int *viewport, float *objectCoordinate)
{
//Transformation matrices
float m[16], A[16];
float in[4], out[4];
//Calculation for inverting a matrix, compute projection x modelview
//and store in A[16]
MultiplyMatrices4by4OpenGL_FLOAT(A, projection, modelview);
//Now compute the inverse of matrix A
if(glhInvertMatrixf2(A, m)==0)
return 0;
//Transformation of normalized coordinates between -1 and 1
in[0]=(winx-(float)viewport[0])/(float)viewport[2]*2.0-1.0;
in[1]=(winy-(float)viewport[1])/(float)viewport[3]*2.0-1.0;
in[2]=2.0*winz-1.0;
in[3]=1.0;
//Objects coordinates
MultiplyMatrixByVector4by4OpenGL_FLOAT(out, m, in);
if(out[3]==0.0)
return 0;
out[3]=1.0/out[3];
objectCoordinate[0]=out[0]*out[3];
objectCoordinate[1]=out[1]*out[3];
objectCoordinate[2]=out[2]*out[3];
return 1;
}
static void glhLookAtf2( float *matrix, float *eyePosition3D,
float *center3D, float *upVector3D )
{
#define ComputeNormalOfPlane ComputeNormalOfPlaneFLOAT_2
#define NormalizeVector NormalizeVectorFLOAT_2
#ifdef BUILD_USE_GLHLIB
float resultMatrix[16];
#endif
float forward[3], side[3], up[3];
float matrix2[16];
//------------------
forward[0] = center3D[0] - eyePosition3D[0];
forward[1] = center3D[1] - eyePosition3D[1];
forward[2] = center3D[2] - eyePosition3D[2];
NormalizeVector(forward);
//------------------
//Side = forward x up
ComputeNormalOfPlane(side, forward, upVector3D);
NormalizeVector(side);
//------------------
//Recompute up as: up = side x forward
ComputeNormalOfPlane(up, side, forward);
//------------------
matrix2[0] = side[0];
matrix2[4] = side[1];
matrix2[8] = side[2];
matrix2[12] = 0.0;
//------------------
matrix2[1] = up[0];
matrix2[5] = up[1];
matrix2[9] = up[2];
matrix2[13] = 0.0;
//------------------
matrix2[2] = -forward[0];
matrix2[6] = -forward[1];
matrix2[10] = -forward[2];
matrix2[14] = 0.0;
//------------------
matrix2[3] = matrix2[7] = matrix2[11] = 0.0;
matrix2[15] = 1.0;
//------------------
#ifdef BUILD_USE_GLHLIB
MultiplyMatrices4by4OpenGL_FLOAT(resultMatrix, matrix, matrix2);
glhTranslatef2(resultMatrix,
-eyePosition3D[0], -eyePosition3D[1], -eyePosition3D[2]);
//------------------
memcpy(matrix, resultMatrix, 16*sizeof(float));
#else
glMultMatrixf(matrix2);
glTranslatef( -eyePosition3D[0], -eyePosition3D[1], -eyePosition3D[2] );
#endif
}
