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mmm
12-17-2000, 02:09 PM
Hi,
If C is the current matrix and I call glMultMatrix{fd} with D, then the NEW current matrix is C*D or D*C?

Thanks
MMM

softland_gh
12-19-2000, 04:24 AM
Well, it depends on how you imagine vertices. If you think verices are presented as rows then it's D*C with D and C formatted in column major. If you think verices are presented as columns then it's C*D with D and C formatted in row major. That's because vertices are multiplied first with the last matrix multiplied with the one in the stack.
In other words:

If V is a coumn then Vt=C*D*V.
If V is a row then Vt=V*D*C.

12-19-2000, 09:14 AM
The red book p. 73 says that after the multiplication is the current matrix always C*D

softland_gh
12-19-2000, 12:13 PM
If you think carefuly of what I posted, you'll see that it's the same. It's a matter of assuming whether vertices are columns or rows.


Originally posted by MatrixMagic:
The red book p. 73 says that after the multiplication is the current matrix always C*D

mmm
12-19-2000, 05:54 PM
Thanks... i think i understood.

marcio