glViewport( x, y, width, height ) defines the area in the window where openGL does its rendering. So if you do something like

  glViewport( 0, 0, 100, 100 );doProjection( 100, 100 );renderWindowA();glViewport( 100, 0, 100, 100 );doProjection( 100, 100 );renderWindowB();glViewport( 0, 100, 200, 100 );doProjection( 200, 100 );renderWindowC();  

You will have 3 images rendered in your window according to the pattern:

AAABBB
AAABBB
AAABBB
CCCCCC
CCCCCC
CCCCCC

@fruny
thx i will try it

--=[[TheMatrixXXX]]=--

Be careful to glFlush() and glutSwapBuffer() only once.

@fruny:
what do you mean with doProjection?
i have my multiple viewport now but i don´t know how to draw on each one
how can i select them?
i know with the renderWindow but where i have to call these funcs ?
and can i use different views? (gluPerspective and 3xglOrtho)

thx
--=[[TheMatrixXXX]]=--

Edited by - TheMatrixXXX on November 19, 2001 1:31:32 PM

If you are doing a projection, it is usually dependent on the width to height ratio of your openGL viewport, no ? So, since I had different sized viewports, I called my doProjection function with the appropriate parameters.

And actually, you don't have several viewports, you have only one. GL will render where you tell it to. That's why I have several renderWindow() functions.

Follow this pattern:

    {  glViewport( whole window );  glClear();  glViewport( a corner );  glWhateverProjection( a corner );  Render( a corner );  glViewport( another corner );  glWhateverProjection( another corner );  Render( another corner );  .  .  .  glFlush();  glutSwapBuffers(); // May have to restore the viewport to the whole window though...}    

If you want separate input processing for each viewport, you are better off with glut sub-windows, as Major pointed out.

Or you can put 4 calls to glutCreateWindow(), register callbacks for each, save the window handle, and use glutSetWindow() in the right places (e.g. before calls to glutPostRedisplay() ).

(Sorry if I sound confused, I've had 3 hours of sleep over the pas 2 days. )

Edited by - Fruny on November 19, 2001 2:04:18 PM

thx i know what you mean

but i want to draw in orthographic views like in a level editor and view the world in a perspective view

i programmed it so far the only problem i have is that the app only show one of four windows and that is a problem of the handles someone told me.

thx
--=[[TheMatrixXXX]]=--