diff options
Diffstat (limited to 'redist/linmath.c')
| -rw-r--r-- | redist/linmath.c | 32 |
1 files changed, 17 insertions, 15 deletions
diff --git a/redist/linmath.c b/redist/linmath.c index 5fefe1e..b3896ff 100644 --- a/redist/linmath.c +++ b/redist/linmath.c @@ -259,35 +259,37 @@ void quatfrommatrix( FLT * q, const FLT * matrix44 ) } +// Algorithm from http://www.euclideanspace.com/maths/geometry/rotations/conversions/quaternionToMatrix/ void quattomatrix33(FLT * matrix33, const FLT * qin) { FLT q[4]; quatnormalize(q, qin); //Reduced calulation for speed - FLT xx = 2 * q[0] * q[0]; - FLT xy = 2 * q[0] * q[1]; - FLT xz = 2 * q[0] * q[2]; - FLT xw = 2 * q[0] * q[3]; + FLT xx = 2 * q[1] * q[1]; + FLT xy = 2 * q[1] * q[2]; + FLT xz = 2 * q[1] * q[3]; + FLT xw = 2 * q[1] * q[0]; + + FLT yy = 2 * q[2] * q[2]; + FLT yz = 2 * q[2] * q[3]; + FLT yw = 2 * q[2] * q[0]; - FLT yy = 2 * q[1] * q[1]; - FLT yz = 2 * q[1] * q[2]; - FLT yw = 2 * q[1] * q[3]; + FLT zz = 2 * q[3] * q[3]; + FLT zw = 2 * q[3] * q[0]; - FLT zz = 2 * q[2] * q[2]; - FLT zw = 2 * q[2] * q[3]; //opengl major matrix33[0] = 1 - yy - zz; - matrix33[1] = xy - zw; - matrix33[2] = xz + yw; + matrix33[1] = xy + zw; + matrix33[2] = xz - yw; - matrix33[3] = xy + zw; + matrix33[3] = xy - zw; matrix33[4] = 1 - xx - zz; - matrix33[5] = yz - xw; + matrix33[5] = yz + xw; - matrix33[6] = xz - yw; - matrix33[7] = yz + xw; + matrix33[6] = xz + yw; + matrix33[7] = yz - xw; matrix33[8] = 1 - xx - yy; } |