On 1/5/07, jamin1001
In C OpenGL, you can do something like this to use matrices for computation without affecting context:
glMatrixMode (GL_MODELVIEW) ; glPushMatrix () ; glLoadMatrix (your_matrix) ; // do whatever you want with your your matrix // for exampl glMultMatrix (your_matrix2) ; ... // at the end of your calculations use glGetFloatv (GL_MODELVIEW_MATRIX, your_matrix_result) ; glPopMatrix () ; // nothing has changed !!!
I'm not exactly sure how this is done with HOpenGL. i.e., how can I get the result of a matrix transformation not effecting the MODELVIEW, etc. matrices? Could someone give an example?
Thanks,
Jamin
glPushMatrix() ; foo ; glPopMatrix(); Is written like so: preservingMatrix foo Often you would write things like do foo preservingMatrix $ do bar baz foo2 Here bar and baz may modify the matrices, but as soon as you leave the scope of the action passed to preservingMatrix, the matrix stack is popped (glPopMatrix()). The Haskell way is better, since there is no way of ever forgetting to pop the matrix - preservingMatrix is like a user defined control structure. That's what first class actions buys you. -- Sebastian Sylvan +46(0)736-818655 UIN: 44640862