Posted by cznlzq on Mar 23, 2012; 8:23pm
URL: https://forum.jogamp.org/question-about-the-GLCanvas-and-GLJPanel-tp3844025p3852684.html

Thank you for the suggestion.

It is very interesting. Indeed we have to call the repaint in the display for the GLCanvas.

However, I found that for the GLJPanel we don't have to call any function.
Just override the paintComponent in GLJPanel then it will take care of everything.

And I recode the test codes to test these two

=========================================================


import java.awt.Color;
import java.awt.Font;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;


import javax.media.opengl.*;
import javax.media.opengl.awt.GLCanvas;
import javax.media.opengl.awt.GLJPanel;

import com.jogamp.opengl.util.FPSAnimator;

public class SimpleScene implements GLEventListener {

    private double theta = 0;
    private double s = 0;
    private double c = 0;

    private static GLCanvas canvas = null;
    private static GLJPanel panel = null;
   
    private static int step = 1;
   
    public static void main(String[] args) {
        GLProfile glp = GLProfile.getDefault();
        GLCapabilities caps = new GLCapabilities(glp);
        caps.setDoubleBuffered(true);
       
        canvas = new GLCanvas(caps){
       
                        @Override
                        public void paint(Graphics arg0) {
                               
                        //System.out.println("paint");

                        // TODO Auto-generated method stub
                        super.paint(arg0);

                        Graphics2D g2 = (Graphics2D)arg0;
                        Font font = new Font("Times", Font.BOLD, 32);
                        g2.setColor(Color.BLUE);
                        g2.setFont(font);
                        g2.drawString("2DRender", 250, 50);
                        }
       
        };

       
        panel =  new GLJPanel(){

                        @Override
                        protected void paintComponent(Graphics arg0) {
                        //System.out.println("paintComponent");
                       
                        // TODO Auto-generated method stub
                        super.paintComponent(arg0);

                        Graphics2D g2 = (Graphics2D)arg0;
                        Font font = new Font("Times", Font.BOLD, 32);
                        g2.setColor(Color.GREEN);
                        g2.setFont(font);
                        g2.drawString("2DRender", 250, 50);
                        }
       
        };
       
        Frame frame = new Frame("AWT Window Test");
        frame.setSize(600, 600);
        frame.add(canvas);
        //frame.add(panel);
        frame.setVisible(true);

        frame.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
       
        canvas.setAutoSwapBufferMode(true);        
        canvas.addGLEventListener(new SimpleScene());
        FPSAnimator animator = new FPSAnimator(canvas, 60);
        animator.add(canvas);    
       
//        panel.setAutoSwapBufferMode(true);        
//        panel.addGLEventListener(new SimpleScene());
//        FPSAnimator animator = new FPSAnimator(panel, 60);
//        animator.add(panel);  
       
        animator.start();
    }

    @Override
    public void display(GLAutoDrawable drawable) {
        update();
        render(drawable);
       
        canvas.repaint();
    }

    @Override
    public void dispose(GLAutoDrawable drawable) {
    }

    @Override
    public void init(GLAutoDrawable drawable) {
    }

    @Override
    public void reshape(GLAutoDrawable drawable, int x, int y, int w, int h) {
    }

    private void update() {
        theta += 0.01;
        s = Math.sin(theta);
        c = Math.cos(theta);
    }

    private void render(GLAutoDrawable drawable) {
        GL2 gl = drawable.getGL().getGL2();

        gl.glClear(GL.GL_COLOR_BUFFER_BIT);

        // draw a triangle filling the window
        gl.glBegin(GL.GL_TRIANGLES);
        gl.glColor3f(1, 0, 0);
        gl.glVertex2d(-c, -c);
        gl.glColor3f(0, 1, 0);
        gl.glVertex2d(0, c);
        gl.glColor3f(0, 0, 1);
        gl.glVertex2d(s, -s);
        gl.glEnd();
    }
}



I can see the drawString things, however, its background doesn't look good and it's flashing.

Did I make something wrong?