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Delorean
04-26-2005, 10:46 AM
Good evening ladies and gentlemen! :cool:

Can anyone throw over example, how vertex coordinate gets windows coordinate with all modelview, projectoin matrixs, perspective divisions and viewport manipulation?

for example, i have a modelView matrix
1 0 0 0 -- X
0 1 0 0 -- Y
0 0 1 0 -- Z
0 0 10 1 -- Camera location

and i want to draw a point at (1,1,1)

homogeneous vector shall be (1,1,11,1).
What happen next?

Thanks in advance.
Regards.
Del.

MMMovania
04-26-2005, 07:00 PM
Originally posted by Delorean:
Good evening ladies and gentlemen! :cool:

Can anyone throw over example, how vertex coordinate gets windows coordinate with all modelview, projectoin matrixs, perspective divisions and viewport manipulation?

for example, i have a modelView matrix
1 0 0 0 -- X
0 1 0 0 -- Y
0 0 1 0 -- Z
0 0 10 1 -- Camera location

and i want to draw a point at (1,1,1)

homogeneous vector shall be (1,1,11,1).
What happen next?

Thanks in advance.
Regards.
Del.Now the homogenous coordinates will be converted based on the type of projection parallel or perspective into the corresponding projection. If you have givn an orthogonal projection (by call to glOrtho then its just doing a simple division between the three coordinates. Otherwise if you are doing a perspective projection using (gluPerspective or glFrustum), the coordinates are actually created by the matrix look it out in the red book if you are interested or let me know I have already dissected the matrices responsible for the parallel and perspective projection. Dude if you are really interested in the matrices and their info I would highly recommend Computer Graphics with openGL by Hearn and Baker I got all the answers from there. still if there is anything else I can always be contacted by email. Send me a PM if you want any assistance. Thanx and best of luck hope this info helps you out.
MMM