static inline int m4_inverse(double *mr, double *ma)
{
double mtemp[9], mdet = m4_det(ma);
int i, j, sign;
if (fabs(mdet) == 0.0)
return 0;
for (i = 0; i < 4; i++)
{
for (j = 0; j < 4; j++)
{
sign = 1 - ((i +j) % 2) * 2;
m4_submat(ma, mtemp, i, j);
mr[i+j*4] = (m3_det(mtemp) * sign) / mdet;
}
}
return 1;
}
int m4x4_invert(m4x4_t matrix)
{
float mdet = m4_det( matrix );
m3x3_t mtemp;
int i, j, sign;
m4x4_t m4x4_temp;
if ( fabs( mdet ) < 0.0000000001 ) //% 0.0005
return 1;
memcpy(m4x4_temp, matrix, sizeof(m4x4_t));
for ( i = 0; i < 4; i++ )
for ( j = 0; j < 4; j++ )
{
sign = 1 - ( (i +j) % 2 ) * 2;
m4_submat( m4x4_temp, mtemp, i, j );
matrix[i+j*4] = ( m3_det( mtemp ) * sign ) / mdet;
}
return 0;
}
static void ExtrapolateTexcoords( const float *axyz, const float *ast, const float *bxyz, const float *bst, const float *cxyz, const float *cst, const float *axyz_new, float *ast_out, const float *bxyz_new, float *bst_out, const float *cxyz_new, float *cst_out ){
vec4_t scoeffs, tcoeffs;
float md;
m4x4_t solvematrix;
vec3_t norm;
vec3_t dab, dac;
VectorSubtract( bxyz, axyz, dab );
VectorSubtract( cxyz, axyz, dac );
CrossProduct( dab, dac, norm );
// assume:
// s = f(x, y, z)
// s(v + norm) = s(v) when n ortho xyz
// s(v) = DotProduct(v, scoeffs) + scoeffs[3]
// solve:
// scoeffs * (axyz, 1) == ast[0]
// scoeffs * (bxyz, 1) == bst[0]
// scoeffs * (cxyz, 1) == cst[0]
// scoeffs * (norm, 0) == 0
// scoeffs * [axyz, 1 | bxyz, 1 | cxyz, 1 | norm, 0] = [ast[0], bst[0], cst[0], 0]
solvematrix[0] = axyz[0];
solvematrix[4] = axyz[1];
solvematrix[8] = axyz[2];
solvematrix[12] = 1;
solvematrix[1] = bxyz[0];
solvematrix[5] = bxyz[1];
solvematrix[9] = bxyz[2];
solvematrix[13] = 1;
solvematrix[2] = cxyz[0];
solvematrix[6] = cxyz[1];
solvematrix[10] = cxyz[2];
solvematrix[14] = 1;
solvematrix[3] = norm[0];
solvematrix[7] = norm[1];
solvematrix[11] = norm[2];
solvematrix[15] = 0;
md = m4_det( solvematrix );
if ( md * md < 1e-10 ) {
Sys_Printf( "Cannot invert some matrix, some texcoords aren't extrapolated!" );
return;
}
m4x4_invert( solvematrix );
scoeffs[0] = ast[0];
scoeffs[1] = bst[0];
scoeffs[2] = cst[0];
scoeffs[3] = 0;
m4x4_transform_vec4( solvematrix, scoeffs );
tcoeffs[0] = ast[1];
tcoeffs[1] = bst[1];
tcoeffs[2] = cst[1];
tcoeffs[3] = 0;
m4x4_transform_vec4( solvematrix, tcoeffs );
ast_out[0] = scoeffs[0] * axyz_new[0] + scoeffs[1] * axyz_new[1] + scoeffs[2] * axyz_new[2] + scoeffs[3];
ast_out[1] = tcoeffs[0] * axyz_new[0] + tcoeffs[1] * axyz_new[1] + tcoeffs[2] * axyz_new[2] + tcoeffs[3];
bst_out[0] = scoeffs[0] * bxyz_new[0] + scoeffs[1] * bxyz_new[1] + scoeffs[2] * bxyz_new[2] + scoeffs[3];
bst_out[1] = tcoeffs[0] * bxyz_new[0] + tcoeffs[1] * bxyz_new[1] + tcoeffs[2] * bxyz_new[2] + tcoeffs[3];
cst_out[0] = scoeffs[0] * cxyz_new[0] + scoeffs[1] * cxyz_new[1] + scoeffs[2] * cxyz_new[2] + scoeffs[3];
cst_out[1] = tcoeffs[0] * cxyz_new[0] + tcoeffs[1] * cxyz_new[1] + tcoeffs[2] * cxyz_new[2] + tcoeffs[3];
}
