Computer graphics -- 2008-2009 -- info.uvt.ro/JOGL-Template

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Complete example

Two example templates are given here. One for scenes using an orthographic projection and one for scenes using a perspective projection. These examples are intended to be used as templates for future JOGL based applications.

Orthographic projection example

import javax.media.opengl.GL;
import javax.media.opengl.GL2;
import javax.media.opengl.GLAutoDrawable;
import javax.media.opengl.GLCapabilities;
import javax.media.opengl.GLEventListener;
import javax.media.opengl.GLProfile;
import javax.media.opengl.awt.GLCanvas;
import javax.media.opengl.fixedfunc.GLMatrixFunc;

import javax.swing.JFrame;

import com.jogamp.opengl.util.Animator;

public class MainFrame
		extends JFrame
		implements GLEventListener
{

	private GLCanvas canvas;
	private Animator animator;

	// For specifying the positions of the clipping planes (increase/decrease the distance) modify this variable.
 	// It is used by the glOrtho method.
	private double v_size = 1.0;

	// Application main entry point
	public static void main(String args[]) 
	{
		new MainFrame();
	}

	// Default constructor
	public MainFrame()
	{
		super("Java OpenGL");
		
		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);	
		
		this.setSize(800, 600);
		
		this.initializeJogl();
		
		this.setVisible(true);
	}
	
	private void initializeJogl()
	{
		// Creating a new GL profile.
		GLProfile glprofile = GLProfile.getDefault();
		// Creating an object to manipulate OpenGL parameters.
		GLCapabilities capabilities = new GLCapabilities(glprofile);
		
		// Setting some OpenGL parameters.
		capabilities.setHardwareAccelerated(true);
		capabilities.setDoubleBuffered(true);

		// Try to enable 2x anti aliasing. It should be supported on most hardware.
	        capabilities.setNumSamples(2);
        	capabilities.setSampleBuffers(true);
		
		// Creating an OpenGL display widget -- canvas.
		this.canvas = new GLCanvas(capabilities);
		
		// Adding the canvas in the center of the frame.
		this.getContentPane().add(this.canvas);
		
		// Adding an OpenGL event listener to the canvas.
		this.canvas.addGLEventListener(this);
		
		// Creating an animator that will redraw the scene 40 times per second.
		this.animator = new Animator(this.canvas);
			
		// Starting the animator.
		this.animator.start();
	}
	
	public void init(GLAutoDrawable canvas)
	{
		// Obtaining the GL instance associated with the canvas.
		GL2 gl = canvas.getGL().getGL2();
		
		// Setting the clear color -- the color which will be used to erase the canvas.
		gl.glClearColor(0, 0, 0, 0);
		
		// Selecting the modelview matrix.
		gl.glMatrixMode(GLMatrixFunc.GL_MODELVIEW);

	}
	
	public void display(GLAutoDrawable canvas)
	{
		GL2 gl = canvas.getGL().getGL2();
		
		// Erasing the canvas -- filling it with the clear color.
		gl.glClear(GL.GL_COLOR_BUFFER_BIT);

		// Add your scene code here
		
		// Forcing the scene to be rendered.
		gl.glFlush();
	}
	
	public void reshape(GLAutoDrawable canvas, int left, int top, int width, int height)
	{
		GL2 gl = canvas.getGL().getGL2();
		
		// Selecting the viewport -- the display area -- to be the entire widget.
		gl.glViewport(0, 0, width, height);
		
		// Determining the width to height ratio of the widget.
		double ratio = (double) width / (double) height;
		
		// Selecting the projection matrix.
		gl.glMatrixMode(GLMatrixFunc.GL_PROJECTION);
		
		gl.glLoadIdentity();
		
		// Selecting the view volume to be x from 0 to 1, y from 0 to 1, z from -1 to 1.
		// But we are careful to keep the aspect ratio and enlarging the width or the height.
		if (ratio < 1)
			gl.glOrtho(-v_size, v_size, -v_size, v_size / ratio, -1, 1);
		else
			gl.glOrtho(-v_size, v_size * ratio, -v_size, v_size, -1, 1);

		// Selecting the modelview matrix.
		gl.glMatrixMode(GLMatrixFunc.GL_MODELVIEW);		
	}
	
	public void displayChanged(GLAutoDrawable canvas, boolean modeChanged, boolean deviceChanged)
	{
		return;
	}

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

Perspective projection example

import com.jogamp.opengl.*;
import com.jogamp.opengl.awt.GLCanvas;
import com.jogamp.opengl.fixedfunc.GLMatrixFunc;
import com.jogamp.opengl.glu.GLU;
import com.jogamp.opengl.util.Animator;

import javax.swing.*;

public class MainFrame
		extends JFrame
		implements GLEventListener
{

	private GLCanvas canvas;
	private Animator animator;

	private GLU glu;

	// Application main entry point
	public static void main(String args[])
	{
		new MainFrame();
	}

	// Default constructor;
	public MainFrame()
	{
		super("Java OpenGL");
		
		// Registering a window event listener to handle the closing event.
		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);	
		
		this.setSize(800, 600);
		
		this.initializeJogl();
		
		this.setVisible(true);
	}
	
	private void initializeJogl()
	{
		// Creating a new GL profile.
		GLProfile glprofile = GLProfile.getDefault();
		// Creating an object to manipulate OpenGL parameters.
		GLCapabilities capabilities = new GLCapabilities(glprofile);
		
		// Setting some OpenGL parameters.
		capabilities.setHardwareAccelerated(true);
		capabilities.setDoubleBuffered(true);

		// Try to enable 2x anti aliasing. It should be supported on most hardware.
	        capabilities.setNumSamples(2);
        	capabilities.setSampleBuffers(true);
		
		// Creating an OpenGL display widget -- canvas.
		this.canvas = new GLCanvas(capabilities);
		
		// Adding the canvas in the center of the frame.
		this.getContentPane().add(this.canvas);
		
		// Adding an OpenGL event listener to the canvas.
		this.canvas.addGLEventListener(this);
		
		// Creating an animator that will redraw the scene 40 times per second.
		this.animator = new Animator(this.canvas);
		
		// Starting the animator.
		this.animator.start();
	}
	
	public void init(GLAutoDrawable canvas)
	{
		// Obtaining the GL instance associated with the canvas.
		GL2 gl = canvas.getGL().getGL2();
		
		// Initialize GLU. We'll need it for perspective and camera setup.
		this.glu = GLU.createGLU();

		// Setting the clear color -- the color which will be used to erase the canvas.
		gl.glClearColor(0, 0, 0, 0);
		
		// Selecting the modelview matrix.
		gl.glMatrixMode(GLMatrixFunc.GL_MODELVIEW);

	}
	
	public void display(GLAutoDrawable canvas)
	{
		GL2 gl = canvas.getGL().getGL2();
		
		// Erasing the canvas -- filling it with the clear color.
		gl.glClear(GL.GL_COLOR_BUFFER_BIT);

		gl.glLoadIdentity();

		// Add your scene code here
		
		// Forcing the scene to be rendered.
		gl.glFlush();
	}
	
	public void reshape(GLAutoDrawable canvas, int left, int top, int width, int height)
	{
		GL2 gl = canvas.getGL().getGL2();
		
		// Selecting the viewport -- the display area -- to be the entire widget.
		gl.glViewport(0, 0, width, height);
		
		// Determining the width to height ratio of the widget.
		double ratio = (double) width / (double) height;
		
		// Selecting the projection matrix.
		gl.glMatrixMode(GLMatrixFunc.GL_PROJECTION);
		
		gl.glLoadIdentity();
		
		glu.gluPerspective (38, ratio, 0.1, 100);

		// Selecting the modelview matrix.
		gl.glMatrixMode(GLMatrixFunc.GL_MODELVIEW);		
	}
	
	public void displayChanged(GLAutoDrawable canvas, boolean modeChanged, boolean deviceChanged)
	{
		return;
	}

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

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• Marc Frîncu, mfrincu@info.uvt.ro