2D Drawing in OpenGL

[LongJumper]

I want to draw something that isn't 3D at all. I guess I'd like to draw something without any projection, kind of like "in the front" of the screen. So when I draw something with the coordinates -.5,.5 as left corner and 0,0 and the bottom right corner, I'd like it to cover exactly 1/4th the screen, the second quadrant. I also need to do this after I draw some projected stuff.

I'm guessing it would have to do something with setting up another camera orthographically, then pushing the matrix calling the camera render function, and drawing?

[FCCovett]

Check this out (in Carbon/C):

http://webpages.charter.net/fccovett/MyGameSource.dmg

http://www.idevgames.com/forum/showthread.php?s=&postid=54475#post54475

[johnMG]

Using glut, I wanted the dimensions of my drawing area to match up with the actual pixels, so I did this:

void my_reshape_func( int w, int h )
{
glViewport( 0, 0, w, h );

glMatrixMode( GL_PROJECTION );
glLoadIdentity();
glOrtho( 0.0, static_cast<double>( w ),
0.0, static_cast<double>( h ),
-1.0, 1.0 );

glMatrixMode( GL_MODELVIEW );
glLoadIdentity();

glutPostRedisplay();
}


You'll need to pass something different than w & h to glOrtho() if you don't want (0.0, 0.0) to be the bottom left corner. Enjoy. :)