Question

I am new to using OpenGL and am experimenting with jogl. I am able to draw triangles without a problem however when I try and draw quads (used in many tutorials) eclipse keeping telling me GL.GL_QUADS cannot be resolved.

gl.glBegin(GL.GL_QUADS);

Not sure what I’m doing wrong.

Thanks,

import java.awt.Frame;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.media.opengl.*;
import javax.media.opengl.awt.GLCanvas;
import com.jogamp.opengl.util.*;

public class SimpleScene implements GLEventListener {
    public static void main(String[] args) {
        GLProfile glp = GLProfile.getDefault();
        GLCapabilities caps = new GLCapabilities(glp);
        GLCanvas canvas = new GLCanvas(caps);

        final Frame frame = new Frame("AWT Window Test");
        frame.setSize(300, 300);
        frame.add(canvas);
        frame.setVisible(true);

        // by default, an AWT Frame doesn't do anything when you click
        // the close button; this bit of code will terminate the program when
        // the window is asked to close
        frame.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                frame.dispose();
                System.exit(0);
            }
        });
    canvas.addGLEventListener(new SimpleScene());
    FPSAnimator animator = new FPSAnimator(canvas, 60);
    animator.add(canvas);
    animator.start();
    }

    @Override
    public void display(GLAutoDrawable arg0) {
        update();
        render(arg0);
    }

    private void update() {
        // TODO Auto-generated method stub

    }
    private void render(GLAutoDrawable drawable) {
        GL2 gl = drawable.getGL().getGL2();
//      gl.glViewport(0, 0, 300, 300); //Possibly use to move around object
        gl.glClear(GL.GL_COLOR_BUFFER_BIT);

        gl.glPushMatrix();
        gl.glTranslatef(-1.5f,1.5f,0.0f);                  // Move left 1.5 units, up 1.5 units, and back 8 units

        gl.glBegin(GL.GL_TRIANGLES); 
        gl.glColor3f(10, 0, 0);
// Begin drawing triangles
        gl.glVertex3f( 0.0f, 1.0f, 0.0f);                   // Top vertex
        gl.glVertex3f(-1.0f,-1.0f, 0.0f);                   // Bottom left vertex
        gl.glVertex3f( 1.0f,-1.0f, 0.0f);                   // Bottom right vertex
        gl.glEnd();                                         // Finish drawing triangles
        gl.glPopMatrix();


    }

    @Override
    public void dispose(GLAutoDrawable arg0) {
        // TODO Auto-generated method stub

    }

    @Override
    public void init(GLAutoDrawable arg0) {
        // TODO Auto-generated method stub

    }

    @Override
    public void reshape(GLAutoDrawable arg0, int arg1, int arg2, int arg3,
            int arg4) {
        // TODO Auto-generated method stub

    }
}

Answer 1

The javax.media.opengl.GL interface contains a subset of OpenGL common to GL 3, GL 2, GL ES 2.0 and GL ES 1.x, and GL_QUADS is not part of this subset.

If you use the javax.media.opengl.GL2, you get GL2.GL_QUADS.