/** * Lesson4.java * * Author: Darren Hodges * Date: 16/12/1999 * * Port of the NeHe OpenGL Tutorial (Lesson 4: "Rotation") * to Java using the GL4Java interface to OpenGL. * */ import java.applet.*; import java.awt.*; import java.awt.event.*; //GL4Java classes import gl4java.GLContext; import gl4java.awt.GLAnimCanvas; public class Lesson4 extends Applet { //Our rendering canvas //We are using GLAnimCanvas because we want the canvas //to be constantly redrawn renderCanvas canvas = null; /** * void init() * * Initialise the applet. */ public void init() { //We will use BorderLayout to layout the applet components setLayout(new BorderLayout()); //Create our canvas and add it to the center of the applet canvas = new renderCanvas(getSize().width, getSize().height); canvas.requestFocus(); add("Center", canvas); } /** * void start() * * Start the applet. */ public void start() { //Start animating the canvas canvas.start(); } /** * void stop() * * Stop the applet. */ public void stop() { //Stop animating the canvas canvas.stop(); } /** * void destroy() * * Destroy the applet. */ public void destroy() { //Stop animating the canvas canvas.stop(); //Destroy the canvas canvas.destroy(); } private class renderCanvas extends GLAnimCanvas implements KeyListener, MouseListener { //Angle For The Triangle float rtri = 0.0f; //Angle For The Quad float rquad = 0.0f; /** * renderCanvas(int w, int h) * * Constructor. */ public renderCanvas(int w, int h) { super(w, h); //Registers this canvas to process keyboard events addKeyListener(this); addMouseListener(this); } /** * void preInit() * * Called just BEFORE the GL-Context is created. */ public void preInit() { //We want double buffering doubleBuffer = true; //But we dont want stereo view stereoView = false; } /** * void init() * * Called just AFTER the GL-Context is created. */ public void init() { //This Will Clear The Background Color To Black gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f); //Enables Clearing Of The Depth Buffer gl.glClearDepth(1.0); //The Type Of Depth Test To Do gl.glDepthFunc(GL_LESS); //Enables Depth Testing gl.glEnable(GL_DEPTH_TEST); //Enables Smooth Color Shading gl.glShadeModel(GL_SMOOTH); //Select The Projection Matrix gl.glMatrixMode(GL_PROJECTION); //Reset The Projection Matrix gl.glLoadIdentity(); //Calculate The Aspect Ratio Of The Window glu.gluPerspective(45.0f, (float)getSize().width / (float)getSize().height, 0.1f, 100.0f); //Select The Modelview Matrix gl.glMatrixMode(GL_MODELVIEW); } /** * void destroy() * * Destroy the canvas. */ public void destroy() { //Destroy the GLContext cvsDispose(); } /** * void reshape(int width, int height) * * Called after the first paint command. */ public void reshape(int width, int height) { //Reset The Current Viewport And Perspective Transformation gl.glViewport(0, 0, width, height); //Select The Projection Matrix gl.glMatrixMode(GL_PROJECTION); //Reset The Projection Matrix gl.glLoadIdentity(); //Calculate The Aspect Ratio Of The Window glu.gluPerspective(45.0f, (float)getSize().width / (float)getSize().height, 0.1f, 100.0f); //Select The Modelview Matrix gl.glMatrixMode(GL_MODELVIEW); } /** * void display() * * Draw to the canvas. */ public void display() { //Ensure GL is initialised correctly if (glj.gljMakeCurrent(true) == false) return; //Clear The Screen And The Depth Buffer gl.glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); //Reset The View gl.glLoadIdentity(); //Move Left 1.5 Units And Into The Screen 8.0 gl.glTranslatef(-1.5f, 0.0f, -8.0f); //Rotate The Triangle On The Y axis gl.glRotatef(rtri, 0.0f, 1.0f, 0.0f); //Draw triangle gl.glBegin(GL_POLYGON); gl.glColor3f(1.0f, 0.0f, 0.0f); //Set The Color To Red gl.glVertex3f(0.0f, 1.0f, 0.0f); //Top gl.glColor3f(0.0f, 1.0f, 0.0f); //Set The Color To Green gl.glVertex3f(-1.0f, -1.0f, 0.0f); //Bottom Left gl.glColor3f(0.0f,0.0f,1.0f); //Set The Color To Blue gl.glVertex3f(1.0f, -1.0f, 0.0f); //Bottom Right gl.glEnd(); //Reset The View gl.glLoadIdentity(); //Move right and into the screen gl.glTranslatef(1.5f, 0.0f, -8.0f); //Rotate The Quad On The X axis gl.glRotatef(rquad, 1.0f, 0.0f, 0.0f); //Draw rectangle gl.glBegin(GL_QUADS); gl.glColor3f(0.5f, 0.5f, 1.0f); //Set The Color To Blue One Time Only gl.glVertex3f(-1.0f, 1.0f, 0.0f); //Top Left gl.glVertex3f(1.0f, 1.0f, 0.0f); //Top Right gl.glVertex3f(1.0f, -1.0f, 0.0f); //Bottom Right gl.glVertex3f(-1.0f, -1.0f, 0.0f); //Bottom Left gl.glEnd(); //Increase The Rotation Variable For The Triangle rtri += 0.2f; //Decrease The Rotation Variable For The Quad rquad -= 0.15f; //Swap buffers glj.gljSwap(); glj.gljFree(true); } /** * void keyTyped(KeyEvent e) * * Invoked when a key has been typed. This event occurs when a key press is followed by a key release. */ public void keyTyped(KeyEvent e) { //We are not handling any keyboard events yet } /** * void keyPressed(KeyEvent e) * * Invoked when a key has been pressed. */ public void keyPressed(KeyEvent e) { //We are not handling any keyboard events yet } /** * void keyReleased(KeyEvent e) * * Invoked when a key has been released. */ public void keyReleased(KeyEvent e) { //We are not handling any keyboard events yet } // Methods required for the implementation of MouseListener public void mouseEntered( MouseEvent evt ) { Component comp = evt.getComponent(); if( comp.equals(this ) ) { requestFocus(); } } public void mouseExited( MouseEvent evt ) { } public void mousePressed( MouseEvent evt ) { } public void mouseReleased( MouseEvent evt ) { } public void mouseClicked( MouseEvent evt ) { Component comp = evt.getComponent(); if( comp.equals(this ) ) { requestFocus(); } } } }