Question

I hope you can help me with a little problem…

I know how to draw a circle, that’s not a problem – here is the code in c#

void DrawEllipse()
{
    GL.Color3(0.5, 0.6, 0.2);
    float x, y, z;
    double t;
    GL.Begin(BeginMode.Points);
    for (t = 0; t <= 360; t += 0.25)
    {
        x = (float)(3*Math.Sin(t));
        y = (float)(3*Math.Cos(t));
        z = (float)0;
        GL.Vertex3(x, y, z);
    }
    GL.End();

}

But there is a problem – when I Rotate ‘Gl.Rotate(angle, axis)’ and then redraw a circle – yeah, it’s still circle in the 3D, but I want a circle in the screen – I mean static circle which is not rotating with 3D object in it… Is that possible? How to repair the code?

Answer 1

Just draw it at a position before the camera!
Use pushMatrix() and popMatrix().

Or you can draw the other things between pushMatrix() and popMatrix(). Then draw the circle.