How do I draw a circle using OpenGL?
Author
Hi there!
I would like to know how do I draw a circle using OpenGL.
Thanks in advance!
Let rad be the radius of the n-gon and c the number of sides then.
float ad=(float)(2.0f*PI)/(float)c;float a=0;for (int i=0;i<c;i++;a+=ad;){ xOfNewPoint=cos(a)*rad; yOfNewPoint=sin(a)*rad;}
That's not legal C, CableGuy. You need to have a comma separating the i++ and the a+=ad. Not to mention, you could use much more descriptive variable names:
int numSides = whateverYouWant;float currentAngle = 0.0f;float deltaAngle= 2.0f*PI / float(numSides); //Difference between each pointglBegin(GL_POLYGON);for( int i = 0; i < numSides; i++ )//Could just have incremented currentAngle until it was >= 2*PI, but this works too{ currentAngle += deltaAngle; //I like this better in here than in the for(). Just aesthetics //Gives the Polygon a new vertex glVertex2f( cos(currentAngle), sin(currentAngle) );}glEnd();
Yeah at first the currentAngle += deltaAngle; was in the for loop but then
I moved it to the for line don't know why, because of that I did the ;, mistake.
And yeah I just copied the code from some old 2d simulator. So the variables' names are a bit hacky.
I moved it to the for line don't know why, because of that I did the ;, mistake.
And yeah I just copied the code from some old 2d simulator. So the variables' names are a bit hacky.
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