MANIPULATING THE CURRENT MATRIX

E.g., if the current matrix is M, and you invoke

glMultMatrix( vN)

where vN is a pointer to a 4x4 matrix array N, then the new current matrix is MN.
-- Call this a right multiplication by N.

Note that in the sequence of matrix transformations

glMatrixMode(GL_MODELVIEW); glMultMatrix( vN1); glMultMatrix( vN2); glMultMatrix( vN3);

we are really transforming a vertex V in the model in reverse order:
-- first by N3, then by N2 and finally by N1.

The model view matrix (M) is a combination of view transformation (N1) and global transformations (N2).
-- Then, M=N1.N2 (and not the other way round).
-- Hence, we normally begin by specifying N1 first in the program, even though, logically, it occurs after all the other global transformations N2 have taken place.

The model view, projection and texture matrices have associated stacks. You can push and pop from this stack. Thus you can save or restore these matrices.