Hi,
I'm new to Java game programming. I read a lot on how to implement a game loop, but I can't quite get it to be smooth. I've look all over the forums and the net and I think I've implemented this correctly, but the thing still jitters or stutters. Here's my test code. It's a very simple game loop.
If you run this, you will see the red box somewhat stutter when moving.
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| import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.image.BufferStrategy;
import javax.swing.JFrame;
public class CTest
implements Runnable {
static final int APP_WIDTH = 640;
static final int APP_HEIGHT = 480;
private GraphicsEnvironment mGraphicsEnv = null;
private GraphicsDevice mGraphicsDev = null;
private GraphicsConfiguration mGraphicsConf = null;
private BufferStrategy mBufferStrategy = null;
private JFrame mFrame = null;
private Graphics2D mGraphics = null;
private long mStart = 0;
private long mEnd = 0;
private long mDT;
private double mSeconds;
private long mSetFPS = (1000/60) * 1000000;
private int mBoxX = 200;
private int mBoxY = 200;
private int mBoxDX = 1;
private int mBoxDY = 1;
CTest() {
mGraphicsEnv = GraphicsEnvironment.getLocalGraphicsEnvironment();
mGraphicsDev = mGraphicsEnv.getDefaultScreenDevice();
mGraphicsConf = mGraphicsDev.getDefaultConfiguration();
mFrame = new JFrame(mGraphicsConf);
mFrame.setIgnoreRepaint(true);
mFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
mFrame.setLocation(100, 100);
mFrame.setSize(APP_WIDTH, APP_HEIGHT);
mFrame.setFocusTraversalKeysEnabled(false);
mFrame.setResizable(false);
mFrame.setVisible(true);
mFrame.createBufferStrategy(2);
mBufferStrategy = mFrame.getBufferStrategy();
Thread thread = new Thread(this);
thread.start();
}
public void run() {
while(true) {
mStart = System.nanoTime();
mBoxX += mBoxDX;
mBoxY += mBoxDY;
if(mBoxX > APP_WIDTH - 50)
mBoxDX = -1;
if(mBoxX < 0)
mBoxDX = 1;
if(mBoxY > APP_HEIGHT - 50)
mBoxDY = -1;
if(mBoxY < 0)
mBoxDY = 1;
mGraphics = (Graphics2D)mBufferStrategy.getDrawGraphics();
mGraphics.clearRect(0, 0, APP_WIDTH, APP_HEIGHT);
mGraphics.setColor(Color.RED);
mGraphics.fillRect(mBoxX, mBoxY, 50, 50);
mGraphics.dispose();
mBufferStrategy.show();
mEnd = System.nanoTime();
mDT = mEnd - mStart;
while(mDT < mSetFPS) {
Thread.yield();
mEnd = System.nanoTime();
mDT = mEnd - mStart;
}
}
}
public static void main(String[] args) {
new CTest();
}
} |
Did I miss something on implementing a good active rendering game loop?
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