# Thread: Drawing a circle using glut...

1. ## Drawing a circle using glut...

I can't seem to draw a circle using glut... anybody knows how to do it... thanx in advance. I think i know the logic and that is to split the circle into individual small lines and outputting them...

2. My original code is this
PHP Code:
``` void function(void){     float calculate (float);     float x,y;     int i;     glClearColor(1.0, 0.0, 1.0, 0.0);         glClear(GL_COLOR_BUFFER_BIT);                   /*Draw axes*/     glColor3f(1.0,1.0,1.0);        //black color     glLineWidth(5); //5 pixels     /*Perform drawing of axes*/     glBegin(GL_LINES);     glVertex2f(0,1);     glVertex2f(0,-1);     glVertex2f(1,0);     glVertex2f(-1,0);     glEnd();          /*Draw Circle*/          glColor3f(0.0,0.0,1.0);     glBegin(GL_LINES);     glLineWidth(3);          for(i=0;i<=500;i++) //no of short lines to be drawn     {         x = radius + (i-1)*0.002;         y= calculate(x);         /*scale*/         x= x * 2 - 1;         y= y * 2 -1;         glVertex2f(x,y);         x = radius + i*0.002;         y= calculate(x);         x= x * 2 - 1;         y= y * 2 -1;         glVertex2f(x,y);     }     glEnd();     glFlush(); } float calculate(float x) {     return radius - x; //pow(x,2) + pow(y,2) = pow(r,2)                         //y = r - x }  ```
I feel the codes a little weird at the circle area. the axes are all right.

3. if you want to do it without floating point calculations look into Bressenhams Circle Drawing Algorithm

4. Code:
```	float x,y;
glBegin(GL_LINES);
glColor3f(0.0f,0.0f,0.0f);

x = (float)radius * cos(359 * PI/180.0f);
y = (float)radius * sin(359 * PI/180.0f);
for(int j = 0; j < 360; j++)
{
glVertex2f(x,y);
x = (float)radius * cos(j * PI/180.0f);
y = (float)radius * sin(j * PI/180.0f);
glVertex2f(x,y);
}
glEnd();```

5. thanx for the help but there is a another question though. Why is there a 'f' at the end of