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circle

OpenGL

Started by mike74 Sep 20, 2005 at 3:27 AM 2 replies 1.2k views

Original Post

mike74

154

mike74

Sep 20, 2005 at 3:27 AM

Is there any easy way to draw a circle in OpenGL? I already tried: glPointSize(25.0); glEnable(GL_POINT_SMOOTH); glBegin(GL_POINTS); glVertex2f(0, 0); glEnd(); But, it seems my graphics card limits the radius to about 5 pixels. mike http://www.coolgroups.com/

Fruny

203

Fruny

Sep 20, 2005 at 3:32 AM

The easiest way to draw a circle is as a regular convex polygon with a large number of sides. Barring that, you can resort to using quadrics (e.g. gluDisk), which pretty much amounts to the same.

zedzeek

164

zedzeek

Sep 20, 2005 at 3:49 AM

use sin + cos with the values 0.0 -> 2*PI in radians

initial_reality

Sep 20, 2005 at 11:13 AM

I think what zedzeek meant is:

glBegin(GL_POLYGON);
for (a=0; a<2*M_PI; a+=2*M_PI/numOfEdges)
glVertex2f(cos(a), sin(a));
glEnd();

moreover, you can compile it (check for glCompile, I think)

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