org.eclipse.swt.snippets.Snippet174.java Source code

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Here is the source code for org.eclipse.swt.snippets.Snippet174.java

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/*******************************************************************************
 * Copyright (c) 2000, 2005 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Sebastian Davids - initial implementation
 *     IBM Corporation
 *******************************************************************************/
package org.eclipse.swt.snippets;

/*
 * SWT OpenGL snippet: draw a square
 * 
 * This snippet requires the experimental org.eclipse.swt.opengl plugin, which
 * is not included in swt by default. For information on this plugin see
 * http://dev.eclipse.org/viewcvs/index.cgi/%7Echeckout%7E/platform-swt-home/opengl/opengl.html
 * 
 * For a list of all SWT example snippets see
 * http://dev.eclipse.org/viewcvs/index.cgi/%7Echeckout%7E/platform-swt-home/dev.html#snippets
 */
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.opengl.*;
import org.eclipse.swt.widgets.*;

public class Snippet174 {

    public static void main(String[] args) {
        Display display = new Display();
        Shell shell = new Shell(display);
        shell.setText("OpenGL in SWT");
        shell.setLayout(new FillLayout());
        final Canvas canvas = new Canvas(shell, SWT.NO_BACKGROUND);
        canvas.addControlListener(new ControlAdapter() {
            public void controlResized(ControlEvent e) {
                resize(canvas);
            }
        });
        final GLContext context = init(canvas);
        shell.addDisposeListener(new DisposeListener() {
            public void widgetDisposed(DisposeEvent e) {
                context.dispose();
            }
        });
        new Runnable() {
            public void run() {
                if (canvas.isDisposed())
                    return;
                render();
                context.swapBuffers();
                canvas.getDisplay().timerExec(50, this);
            }
        }.run();
        shell.open();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch())
                display.sleep();
        }
        display.dispose();
    }

    static GLContext init(Canvas canvas) {
        GLContext context = new GLContext(canvas);
        context.setCurrent();
        resize(canvas);
        GL.glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
        GL.glColor3f(0.0f, 0.0f, 0.0f);
        GL.glClearDepth(1.0f);
        GL.glEnable(GL.GL_DEPTH_TEST);
        GL.glHint(GL.GL_PERSPECTIVE_CORRECTION_HINT, GL.GL_NICEST);
        return context;
    }

    static void render() {
        GL.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);
        GL.glLoadIdentity();
        GL.glTranslatef(0.0f, 0.0f, -6.0f);
        GL.glBegin(GL.GL_QUADS);
        GL.glVertex3f(-1.0f, 1.0f, 0.0f);
        GL.glVertex3f(1.0f, 1.0f, 0.0f);
        GL.glVertex3f(1.0f, -1.0f, 0.0f);
        GL.glVertex3f(-1.0f, -1.0f, 0.0f);
        GL.glEnd();
    }

    static void resize(Canvas canvas) {
        Rectangle rect = canvas.getClientArea();
        int width = rect.width;
        int height = Math.max(rect.height, 1);
        GL.glViewport(0, 0, width, height);
        GL.glMatrixMode(GL.GL_PROJECTION);
        GL.glLoadIdentity();
        float aspect = (float) width / (float) height;
        GLU.gluPerspective(45.0f, aspect, 0.5f, 400.0f);
        GL.glMatrixMode(GL.GL_MODELVIEW);
        GL.glLoadIdentity();
    }
}