hi, just wanna ask this. We all know that using gluperspective or glulookat generates matrices. These matrices are used to transform the points. Does anyone know when the multiplication is done? I mean the exact point.
the modelview matrix is multiplied as soon as you do the gluperspective or glulookat.
// modelview is identity
// modelview is the camera matrix
// model view is camera matrix * translate matrix
the resulting point will be :
P = cam_matrix * translate * point_coordinates
you should read this paper : http://www.opengl.org/developers/code/mjktips/TimHall_Reflections.txt
at the beginning it explains all this very well, even if after it goes on explaining reflections.
gluPerspective and gluLookAt don’t just generate a matrix, they multiply that matrix with the current matrix. The multiplication is immediate, but it is a little more complicated than that.
There are two matrices – model-view and projection. Generally, you use gluPerspective with the projection matrix and gluLookAt with the model-view matrix.
When you call glVertex, the position is multiplied by both matrices to get the location on the screen.
U guys are superb. Thx a million. appreciate it.