Rotate polygon

Hi, I’m new to learning openGL and have a problem.

I’v drawn a basic polygon and am trying to rotate it (around an axis). It rotates just fine but when it does there are 2 polygons.

There is one polygon which is stable and the other rotates.

I want to know how I can blank out the stationary polygon…any help with this would be great.

I’m rotating it with the code below: which is in my display method

          	gl.glRotated(Rot, 0,0,1);


and have defined Rot in my Render canvas class

you should be using glutPostRedisplay()in your drawScene function. glutPostredisplay reshreshes the screeen each time the scene is drawn.

The drawing code looks correct, but are you clearing the matrix and screen each time you draw the the polygon?

void my_loop( void )

void Draw_scene(void)
glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); //Clear the screen

glMatrixMode (GL_PROJECTION); // Tell opengl that we are doing project matrix work
glLoadIdentity(); // Clear the matrix
glOrtho(-8.0, 8.0, -8.0, 8.0, 0.0, 30.0); // Setup an Ortho view
glMatrixMode(GL_MODELVIEW); // Tell opengl that we are doing model matrix work. (drawing)
glLoadIdentity(); // Clear the model matrix

// Draw Polygon

// if drawing done flush or if double buffering used
// swap here, else return

Are you using opengl under what languge Java, V basic, other?

[This message has been edited by nexusone (edited 03-11-2003).]

I’m using Java,
I’v tried as you’v said but I’m still getting the stationary polygon. I’m a bit unsure about how to refresh the buffers

Thanks for your help

Yay it works, i just wasn’t calling the method from the right place!!

Thanks very much for your help