title: How to draw only 1/4 of a circle in OpenGL C++
body: <p>I'm trying to draw only a sector/part of a circle, but currently I always get a full circle.</p>
  
  <p>I use this to draw a circle:</p>
  
  <pre><code>glColor3f (0.25, 1.0, 0.25);
  GLfloat angle, raioX=0.3f, raioY=0.3f;
  GLfloat circle_points = 100.0f;
  
  glBegin(GL_LINE_LOOP);
  for (int i = 0; i &lt; circle_points; i++) {
      angle = 2*PI*i/circle_points;
      glVertex2f(0.5+cos(angle)*raioX, 0.5+sin(angle)*raioY);        
  }
  glEnd();
  </code></pre>