title: Single point line (two verteces on top of each other) = NO POINT DRAWN?
body: <p>Code is currently:</p>
  <pre><code>with TOpenGLAPIVersion110 do
  begin
  // render ray
  glLineWidth( 1 );
  glBegin(GL_LINES);
  
  // begin of ray is dark gray
  glColor3f( 0.25, 0.25, 0.25 );
  glVertex2f( mRay.Start.X, mRay.Start.Y);
  
  glColor3f( 0.75, 0.75, 0.75 );
  glVertex2f( mRay.Stop.X, mRay.Stop.Y);
  
  glEnd();
  end;
  </code></pre>
  <p>When x,y,z coordinates of Ray.Start is equal to those of Ray.Stop OpenGL does not draw a &quot;point&quot;.</p>
  <p>Why is this ?</p>
  <p>Are the end points of lines &quot;not inclusive&quot; ?</p>