Can someone please explain (or give a hint or suggestion, anything) how to create "sub windows" like those used in Nate Robins'' GL Tutors (http://www.xmission.com/%7Enate/tutors.html) without using glut? I feel like I''ve run into a brick wall with my project. Thanks, diddly

He probably uses scissor testing, from what I can tell from the screen shots.

Play with the glViewport command : set a viewport, render, repeat.

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[edited by - Fruny on May 30, 2002 3:27:57 PM]

Ok, that brings up another question I have been meaning to ask. What exactly (ok, not exactly, just generally) does the glViewport() command do? I have tried playing around with it, but I can''t seem to understand what it does. I read the documentation on msdn, but I am unclear on a few (read: many) things. When it refers to "affine coordinates" and "normalized device coordinates," what is it talking about?

Thanks for the help,
diddly

glViewport controls the window coordinates, where in the window will the GL scene be drawn.

Imagine you have a window origin (0,0) dimensions (w,h).
glViewport(0,0,w,h) makes you render to the whole window
glViewport(0,0,w/2,h/2) makes you render to the upper-left quarter.


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Oh right, so is that how the picture-in-picture in Counter-strike is done?

Henrym

[edited by - henrym on June 2, 2002 5:06:54 PM]

How are the coordinates numbered? Is (0, 0) the upper left or bottom left corner?

diddly

quote:

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Original post by diddly-yo
How are the coordinates numbered? Is (0, 0) the upper left or bottom left corner?

diddly

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glViewport


bottom left, but checkout the MSDN for further information on the function, as well as all OpenGL functions....

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I guess that''s how you would do split screen rendering, as well? Like, for a simultaneous two player game?

Yep. Just set the viewport to the top half of the screen, render for player 1, set vieport to bottom half, render for player 2.

Be sure you set the perspective correctly. Instead of the windowheight, use windowheight/2.

Sander Maréchal

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