PDA

View Full Version : Computing inverse of model view matrix



chipheo
03-09-2001, 10:16 AM
Hello everyone,

Is there anyway we can get the inverse matrix of the model view matrix in OpenGL efficiently? Of course, we could get that matrix by glGetDoublev(GL_MODELVIEW_MATRIX,m) and then compute the inverse of m manually, but it's way too long since internally, I think, OpenGL must use the inverse to transform normal vectors.

Any help would be greatly appreciated.

Chip

DFrey
03-09-2001, 10:56 AM
That is the only way to do it generally. However, if you happen to know that the model view matrix is only a concatenation of rotation matrices, then computing the inverse is trivial, its just the transposition.