Java example source code file (VSyncedBufferStrategyTest.java)

This example Java source code file (VSyncedBufferStrategyTest.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

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Java - Java tags/keywords

actionlistener, awt, block_w, buffercapabilities, event, frame, gui, imagecapabilities, interruptedexception, jbutton, note, override, runtimeexception, swing, threading, threads, v\-synced, vsyncedbufferstrategytest

The VSyncedBufferStrategyTest.java Java example source code

/*
 * Copyright (c) 2007, 2008, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
/*
 * @test
 * @bug 6678218 6681745 6691737
 * @summary Tests that v-synced BufferStrategies works (if vsync is supported)
 * @author Dmitri.Trembovetski@sun.com: area=Graphics
 * @compile -XDignore.symbol.file=true VSyncedBufferStrategyTest.java
 * @run main/manual/othervm VSyncedBufferStrategyTest
 * @run main/manual/othervm -Dsun.java2d.opengl=True VSyncedBufferStrategyTest
 */

import java.awt.AWTException;
import java.awt.BufferCapabilities;
import java.awt.BufferCapabilities.FlipContents;
import java.awt.Button;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.HeadlessException;
import java.awt.ImageCapabilities;
import java.awt.Panel;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.image.BufferStrategy;
import java.util.concurrent.CountDownLatch;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;

public class VSyncedBufferStrategyTest extends Canvas implements Runnable {

    private static final int BLOCK_W = 50;
    private static final int BLOCK_H = 200;

    BufferStrategy bs;
    Thread renderThread;

    int blockX = 10;
    int blockY = 10;

    private volatile boolean done = false;
    private volatile boolean requestVSync;
    private boolean currentBSVSynced;

    public VSyncedBufferStrategyTest(boolean requestVSync) {
        this.requestVSync = requestVSync;
        this.currentBSVSynced = !requestVSync;
        renderThread = new Thread(this);
        renderThread.start();
    }

    private static final BufferCapabilities defaultBC =
        new BufferCapabilities(
                new ImageCapabilities(true),
                new ImageCapabilities(true),
                null);

    private void createBS(boolean requestVSync) {
        if (bs != null && requestVSync == currentBSVSynced) {
            return;
        }

        BufferCapabilities bc = defaultBC;
        if (requestVSync) {
            bc = new sun.java2d.pipe.hw.ExtendedBufferCapabilities(
                    new ImageCapabilities(true),
                    new ImageCapabilities(true),
                    FlipContents.COPIED,
                    sun.java2d.pipe.hw.ExtendedBufferCapabilities.VSyncType.VSYNC_ON);
        }
        try {
            createBufferStrategy(2, bc);
        } catch (AWTException e) {
            System.err.println("Warning: cap is not supported: "+bc);
            e.printStackTrace();
            createBufferStrategy(2);
        }
        currentBSVSynced = requestVSync;
        bs = getBufferStrategy();
        String s =
            getParent() instanceof Frame ?
                ((Frame)getParent()).getTitle() : "parent";
        System.out.println("Created BS for \"" + s + "\" frame, bs="+bs);
    }

    @Override
    public void paint(Graphics g) {
    }
    @Override
    public void update(Graphics g) {
    }

    @Override
    public void run() {
        while (!isShowing()) {
            try { Thread.sleep(5); } catch (InterruptedException e) {}
        }
        try { Thread.sleep(2000); } catch (InterruptedException e) {}

        try {
            while (!done && isShowing()) {
                createBS(requestVSync);
                do {
                    step();
                    Graphics g = bs.getDrawGraphics();
                    render(g);
                    if (!bs.contentsRestored()) {
                        bs.show();
                    }
                } while (bs.contentsLost());
                Thread.yield();
            }
        } catch (Throwable e) {
            // since we're not bothering with proper synchronization, exceptions
            // may be thrown when the frame is closed
            if (isShowing()) {
                throw new RuntimeException(e);
            }
        }
    }

    int inc = 5;
    private void step() {
        blockX += inc;
        if (blockX > getWidth() - BLOCK_W - 10) {
            inc = -inc;
            blockX += inc;
        }
        if (blockX < 10) {
            inc = -inc;
            blockX += inc;
        }
    }

    private void render(Graphics g) {
        g.setColor(Color.white);
        g.fillRect(0, 0, getWidth(), getHeight());

        g.setColor(Color.black);
        g.fillRect(blockX, blockY, BLOCK_W, BLOCK_H);
    }

    private void setRequestVSync(boolean reqVSync) {
        requestVSync = reqVSync;
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension(BLOCK_W*10+20, BLOCK_H+20);
    }

    private static int frameNum = 0;
    private static Frame createAndShowBSFrame() {
        final Frame f = new Frame("Not V-Synced");

        int myNum;
        synchronized (VSyncedBufferStrategyTest.class) {
            myNum = frameNum++;
        }

        final VSyncedBufferStrategyTest component =
                new VSyncedBufferStrategyTest(false);
        f.setIgnoreRepaint(true);
        f.add("Center", component);

        Panel p = new Panel();

        Button b = new Button("Request VSync");
        b.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                f.setTitle("Possibly V-Synced");
                component.setRequestVSync(true);
            }
        });
        p.add(b);

        b = new Button("Relinquish VSync");
        b.addActionListener(new ActionListener() {
            int inc = 1;
            public void actionPerformed(ActionEvent e) {
                f.setTitle("Not V-Synced");
                component.setRequestVSync(false);
                f.setSize(f.getWidth()+inc, f.getHeight());
                inc = -inc;
            }
        });
        p.add(b);

        f.add("South", p);

        f.pack();
        f.setLocation(10, myNum * f.getHeight());
        f.setVisible(true);
        f.addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                component.done = true;
                f.dispose();
            }
            @Override
            public void windowClosed(WindowEvent e) {
                component.done = true;
            }
        });

        return f;
    }

    private static final String description =
        "Tests that v-synced BufferStrategy works. Note that it in some\n" +
        "cases the v-sync can not be enabled, and it is accepted.\n" +
        "The following however is true: only one buffer strategy at a time can\n"+
        "be created v-synced. In order for other BS to become v-synced, the one\n"+
        "that currently is v-synched (or its window) needs to be disposed.\n" +
        "Try the following scenarios:\n" +
        "  - click the \"Request VSync\" button in one of the frames. If the\n"+
        "    behavior of the animation changes - the animation becomes smooth\n" +
        "    it had successfully created a v-synced BS. Note that the animation\n" +
        "    in other frames may also become smoother - this is a side-effect\n"+
        "    of one of the BS-es becoming v-synched\n" +
        "  - click the \"Relinquish VSync\" button on the same frame. If the\n"+
        "    behavior changes to the original (tearing)- it had successfully\n" +
        "    created a non-vsynced strategy.\n" +
        "  - next, try making another one v-synced. It should succeed.\n" +
        "  - next, try making another one v-synced - while there's already\n" +
        "    a v-synced frame. It should not succeed - meaning, it shouldn't\n" +
        "    appear to become smoother, and the behavior of the current v-synced\n" +
        "    frame shouldn't change.\n" +
        "\n" +
        "If there aren't any BufferStrategy-related exceptions or other\n" +
        "issues, and the scenarios worked, the test passed, otherwise it\n"+
        "failed.\n";

    private static void createAndShowDescGUI(final Frame f3, final Frame f1,
                                             final Frame f2)
        throws HeadlessException, RuntimeException
    {
        final JFrame desc =
            new JFrame("VSyncedBufferStrategyTest - Description");
        desc.addWindowListener(new WindowAdapter() {

            @Override
            public void windowClosing(WindowEvent e) {
                f1.dispose();
                f2.dispose();
                f3.dispose();
                l.countDown();
            }
        });
        JPanel p = new JPanel();
        JButton bPassed = new JButton("Passed");
        bPassed.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                desc.dispose();
                f1.dispose();
                f2.dispose();
                f3.dispose();
                l.countDown();
            }
        });
        JButton bFailed = new JButton("Failed");
        bFailed.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                failed = true;
                desc.dispose();
                f1.dispose();
                f2.dispose();
                f3.dispose();
                l.countDown();
            }
        });
        p.setLayout(new FlowLayout());
        p.add(bPassed);
        p.add(bFailed);
        JTextArea ta = new JTextArea(24, 75);
        ta.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 12));
        ta.setEditable(false);
        ta.setText(description);
        desc.add("Center", new JScrollPane(ta));
        desc.add("South", p);
        desc.pack();
        desc.setLocation(BLOCK_W*10+50, 0);
        desc.setVisible(true);
    }

    private static void createTestFrames() {
        Frame f1 = createAndShowBSFrame();
        Frame f2 = createAndShowBSFrame();
        Frame f3 = createAndShowBSFrame();
        createAndShowDescGUI(f1, f2, f3);
    }

    static boolean failed = false;
    static CountDownLatch l = new CountDownLatch(1);
    public static void main(String[] args) throws Exception {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                createTestFrames();
            }
        });
        l.await();
        if (failed) {
            throw new RuntimeException("Test FAILED");
        }
        System.out.println("Test PASSED");
    }

}