Question

Drawing circles in OpenGL

Asked by: Pacman

I need to draw circles using OpenGL with Windows NT. The drawing routing should be very fast.
The frame-code is:

        glViewport(0, 0, w, h);
        glLoadIdentity();
        glOrtho(xmin, xmax, ymin, ymax, 1.0f, -1.0f);

        glInitNames();
        glPushName(1);


        glIndexi(0);
        glRectf( DirtyRect.GetX1(), DirtyRect.GetY1(), DirtyRect.GetX2(), DirtyRect.GetY2() );


        // 1. paint here something

        // 2. now paint a circle at, say (45.4 / -12.2  with radius 4.34)
        // BUT HOW ????



        glFlush();

Does anybody know a good algorithm or possibility in OpenGL ?
(P.S.: no solid circles needed).

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Asked On
1998-04-07 at 06:52:36ID10046741
Tags

circles

,

fast

,

opengl

Topic

Windows Programming

Participating Experts
1
Points
100
Comments
4

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Answers

 

by: RONSLOWPosted on 1998-04-07 at 18:48:33ID: 1412591

gluDisk

 

by: RONSLOWPosted on 1998-04-07 at 18:49:23ID: 1412592

or gluCylinder

 

by: RONSLOWPosted on 1998-04-07 at 19:44:28ID: 1412593

If you don't want to use these directly, then you can get the source code for either of these routines and see how they generate the coordinates for the circle

 

by: PacmanPosted on 1998-04-08 at 23:36:03ID: 1412594

It works. Thank you.

20120131-EE-VQP-002

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