trying cool stuff with mutliple viewports??

OpenGL OpenGL: Advanced Coding
1

I tried this on the beginner board… and received no replies… I hope on this board I get better luck.

well, ever played Starfox64 multiplayer with less than 4 players? if so, you’ve noticed the “camera” quadrant(s). That’s what I am trying to accomplish (in a very basic way).
my window size: 480x240

so, my first guess was… setting the Viewport in my InitGL() by:

glMatrixMode(GL_PROJECTION);
glLoadIdentity();

glViewport(0,0,240,240);
glOrtho(-2.0f,2.0f,-2.0f,2.0f,-1.0f,1.0f);

glViewport(240,0,240,240);
glOrtho(-2.0f,2.0f,-2.0f,2.0f,-1.0f,1.0f);

glMatrixMode(GL_MODELVIEW);

So… in my DrawScene() i drew a circle with r=1 at the origin… I expected to see two circles, but instead I only got the right viewport… perhaps I was mistakened but I thought you would specify the viewport, and then assign the clipping plane to it… and you could do this over and over… but, am I mistakened? if so, how else could I do what I want to do?

2

Can someone PLEEEEEEEEEEEEEEEEEASE HELP ME?!?

I have no idea how to get around this…

3

You can only draw to one viewport at a time.
Set the first viewport, draw the scene for it, set the second viewport, draw the scene for it. And so on.

4

I guess that works… thanks a lot though =)

[This message has been edited by ngill (edited 07-09-2000).]

5

"and then assign the clipping plane to it… "

Be careful, though the glViewport sets the matrix for the final viewport transformation and thereby the viewing frustum planes, it does not set 2D clipping like you need it for glClear.
You probably won’t have the problem because you clear the whole window each frame, but if you have to clear a single viewport you’ll have to use glScissor() and enable scissor test.

6

Cool , I haven’t gotten to the Scissors (sp?) stuff yet… but I think I can read ~300 pages in a week . I have nothing to do… I love the summer…