I have been reading a lot about Double Buffering as I am working on a 2D game. I have come across many different strategies for implementation, but am unsure how Double Buffering would fit into the way I have created my game window. For example, one article I came across (http://content.gpwiki.org/index.php/Java:Tutorials:Double_Buffering) suggested having a separate method for drawing; however, I suspect this would be applicable if you were drawing shapes, instead of adding components to the window.
Here is my main GUI code (keylistener methods omitted)
public class MainWindow extends JFrame implements KeyListener{
private Dimension dim;
private CardLayout layout;
private JPanel panel;
private JLayeredPane gameLayers;
private Menu menu;
private MiniGame miniGame;
private Board board;
private Sprite sprite;
private Game game;
private Map map;
private GameState gs;
private Boolean[] keys;
public MainWindow(Game game, GameState gs, Map map, Sprite sprite){
//Call superclass.
super();
addKeyListener(this);
//Sore references to critical game components.
this.game = game;//So we can call methods when an event occurs.
this.gs = gs;
this.map = map;//Used to construct the board.
//The board needs to know the layout of the map.
this.sprite = sprite;//Used to add the sprite to one of the layers.
//Instantiate objects.
dim = new Dimension(800, 600);
layout = new CardLayout();
panel = new JPanel(layout);
menu = new Menu();
miniGame = new MiniGame();
board = new Board(map);
gameLayers = new JLayeredPane();
//Remove decoration and place window in center of screen.
setUndecorated(true);
Dimension screenDim = Toolkit.getDefaultToolkit().getScreenSize();
setBounds((screenDim.width /2)-(dim.width/2),
(screenDim.height/2)-(dim.height/2),
dim.width,
dim.height);
//Add the board to a layer.
gameLayers.add(board, JLayeredPane.DEFAULT_LAYER);
board.setBounds(0, 0, dim.width, dim.height);
board.setBoard();
//Add the sprite to a layer.
gameLayers.add(sprite, JLayeredPane.PALETTE_LAYER);
sprite.setBounds(0, 0, 50, 50);
//Add components to window.
panel.add(gameLayers, "gameLayers");
panel.add(miniGame, "miniGame");
panel.add(menu, "menu");
//Add the "cards" to the window.
add(panel);
//JFrame housekeeping.
pack();
setSize(dim);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setResizable(false);
setVisible(true);
//Holds state when an event is triggered.
//Ugly hack to circumvent delay issue.
keys = new Boolean[4];
for(int i=0; i<keys.length; i++){
keys[i] = false;
}
}
}
How would you recommend I approach this? Bearing in mind that the Board is a JPanel consisting of a grid of scaled images, and the sprite will be a JComponent displaying a scaled image.
Regards,
Jack.
Override the JPanel's paintComponent() Method and paint the content into a BufferedImage image first. Once done, copy the content of the BufferedImage into the graphics context you get from paintComponent().
protected void paintComponent(Graphics g)
{
BufferedImage bufferedImage = new BufferedImage(500, 500, BufferedImage.TYPE_ARGB);
Graphics2D g2d = bufferedImage.createGraphics();
//paint using g2d ...
Graphics2D g2dComponent = (Graphics2D) g;
g2dComponent.drawImage(bufferedImage, null, 0, 0);
}
As the Java Graphics Library is not fast, either well functional, you should inform yourself about the 'Lightweight Java Game Library' ( http://lwjgl.org/ ). It uses OpenGL, a strong Graphics Library, using native code.
Lwjgl is also used for the game Minecraft.
Also, OpenGL is used for different languages, so you could learn multi-functional and high-level programming.
Related
I'm trying to make a game of chess, but when I try to insert chess pieces through JLabel icons, they cover the actual chessboard, thus only having the pieces left on screen. How do I make the JLabels not cover up paintings behind it? I'm doing this using a class that extends JApplet.
UPDATE: it worked by using Applet instead of JApplet, though I still have no idea why.
This is the code:
ChessBoard board; // done in another class file
public static int CEL_WIDTH = 65;
public static int MARGIN_X = 50, MARGIN_Y = 50;
imagePos = "../src/Schack/Bilder/";
JLabel label;
public void init() {
setLayout(null);
this.setSize(600, 600);
board = new ChessBoard(MARGIN_X, MARGIN_Y, CEL_WIDTH);
ImageIcon imageIcon = new ImageIcon(getImage(getDocumentBase(), imagePos + "blackRook.png")); //scaling my image
Image image = imageIcon.getImage();
Image newimg = image.getScaledInstance(CEL_WIDTH, CEL_WIDTH, java.awt.Image.SCALE_SMOOTH);
imageIcon = new ImageIcon(newimg);
label = new JLabel(imageIcon);
label.setBounds(MARGIN_X, MARGIN_Y, CEL_WIDTH, CEL_WIDTH);
add(label);
}
#Override
public void paint(Graphics g) {
board.paintChessBoard(g); // another paint method in a different class file
super.paint(g);
}
I wish to draw an HUD of sorts over a 3D OpenGL view, but it seems any drawing done in my panel will be overlooked, although it is done.
Here's some barebones code.
MyFrame;
public class MyFrame extends JFrame{
private static final long serialVersionUID = 1L;
public MyFrame(Labyrinth l){
super();
this.setTitle("My Frame");
this.setSize(512, 384);
this.setContentPane(new MyPanel());
//this.setVisible(true);//If needed here.
}
}
MyPanel;
public class MyPanel extends JPanel {
private static final long serialVersionUID = 1L;
public MyPanel(){
super();
this.setLayout(new BorderLayout());
MyCanvas mc=new MyCanvas(l);
mc.setFocusable(false);
this.add(this.mc, BorderLayout.CENTER);
//this.revalidate();//Doesn't seem needed in the instanciation.
}
public void paintComponent(Graphics g){
super.paintComponent(g);
this.mc.repaint();
g.setColor(new Color(128,128,128));
g.fillRect(0, 0, this.getWidth()/2,this.getHeight()/2);
//top-left quarter should be greyed away.
}
}
MyCanvas;
public class MyCanvas extends GLCanvas{
private static final long serialVersionUID = 1L;
public MyCanvas(){
super(new GLCapabilities(GLProfile.getDefault()));
}
}
The painting takes place, but isn't shown in the view. I've tried overriding repaint(), paint(Graphics), paintComponent(Graphics) and update(). I've been said that painting over "heavyweight" components was complicated, and that I should either paint directly in the component or use another type. I obviously need the GLCanvas to show a 3D render, and at the same time it does not seem to provide tools to draw an overlay. Someone told me to simply do my drawing in the JFrame's glassPane however that seems rather overkill, and I've been told never to play around the glassPane so I'm not planning on doing that.
I've seen many topics on the paintings call order but I cannot establish which would be correct while overriding such or such method, and I don't even know if or which method I should override. Is there an obvious way I'd have missed to have my simple JPanel paintings shown over its GLCanvas component?
First of all, I really wouldn't recommend getting a HUD through those means. As I can only imagine this hurting performance a lot. Granted I have never tried mixing Java, OpenGL and AWT's Graphics like that.
Now instead of using holding those classes together with duct tape, consider using JLayeredPane.
JLayeredPane layeredPane = new JLayeredPane();
layeredPane.add(new MyCanvas());
layeredPane.add(new MyPanel());
frame.add(layeredPane);
Now the important part is that you must manually set the bounds of both components:
canvas.setBounds(x, y, width, height);
panel.setBounds(x, y, width, height);
If not you'll end up with the same problem as before:
The painting takes place, but isn't shown in the view
To demonstrate it working I created this small TestPanel class similar to your MyPanel.
public static class TestPanel extends JPanel {
private Color color;
public TestPanel(Color color) {
this.color = color;
}
#Override
public void paintComponent(Graphics g) {
g.setColor(color);
g.drawRect(0, 0, getWidth() - 1, getHeight() - 1);
}
}
Then creating two instances like this:
JPanel panel1 = new TestPanel(new Color(255, 0, 0));
panel1.setBounds(25, 25, 100, 100);
JPanel panel2 = new TestPanel(new Color(0, 0, 255));
panel2.setBounds(75, 75, 100, 100);
Then adding them to a JLayeredPane and adding that to a JFrame and we see this:
I found using the JFrame glass-panel to be a good solution, I use it to draw debugging text on top of 3D graphics, I haven't experienced any problems with it. Using the glass-panel method is more convenient than using a JLayeredPane because the resizing of the 3D panel will be handled for you. Note the 3D graphics must be drawn in a GLJPanel component or the layering won't work (as opposed to GLCanvas which is not a Swing component). The paintComponent(Graphics g) will be called at the same rate as the frame-rate of the GLJPanel. Note also, the glass-pane is hidden by default so setVisible(true) must be called on it.
import javax.swing.JFrame;
import com.jogamp.opengl.awt.GLJPanel;
// ...
public class ApplicationWindow extends JFrame {
public ApplicationWindow(String title) {
super(title);
GLCapabilities gl_profile = new GLCapabilities(GLProfile.getDefault());
GLJPanel gl_canvas = new GLJPanel(gl_profile);
// ... code here to draw the graphics (supply a GLEventListener to gl_canvas)
setContentPane(gl_canvas);
StatusTextOverlayPanel myGlassPane = new StatusTextOverlayPanel();
setGlassPane(myGlassPane);
myGlassPane.setVisible(true);
setVisible(true);
}
class StatusTextOverlayPanel extends JComponent {
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
g2d.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 14));
g2d.setPaint(Color.BLACK);
String statusText = String.format("C-elev: %.2f S-view %.2f D-view %.2f", 1459.0, 17.0, 2.574691);
g2d.drawString(statusText, 10, 20);
}
}
}
Here is an example of what it could look like (You'll need additional code to draw the axis and the square shown)
I'm making simple game in Java and I'm using Swing. I have JFrame and inside it I want to have two JPanels - one for score and so on and second below, for actual game. I read that every JPanel has its own coordinates, so point (0, 0) is on the upper-left corner of that panel.
I override method paintComponent() im my class GameView which displays the game (so it's the second JPanel from these I mentioned). But when I want to draw something in upper-left corner of gameView and set coordinates of that image to (0,0) it draws on BarView.
I read many tutorials and posts about drawing and I don't see what am I doing wrong. So my question is, how to draw something using JPanel coordinates, not JFrame ones? Here's some code:
Adding objects extending JPanel to JFrame:
GameView v = new GameView();
BarView bv = new BarView();
frame.getContentPane().add(bv);
frame.getContentPane().add(v);
frame.setVisible(true);
v.requestFocus();
v.repaint();
bv.repaint();
Drawing in JPanel:
public class GameView extends JPanel implements View, Commons{
public static final int WIDTH=WINDOW_WIDTH, HEIGHT=ARENA_HEIGHT;
private GameScene gameScene;
private TexturePaint paint;
private BufferedImage bi;
public GameView(){
addKeyListener(new CustomKeyListener());
addMouseMotionListener(new CustomMouseListener());
setSize(WINDOW_WIDTH, ARENA_HEIGHT);
setFocusable(true);
try {
bi = ImageIO.read(new File("src/res/texture.png"));
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
this.paint = new TexturePaint(bi, new Rectangle(0, 0, bi.getWidth(), bi.getHeight()));
}
#Override
public void paintComponent(Graphics g1) {
Graphics2D g = (Graphics2D) g1;
g.setPaint(paint);
g.fillRect(0, 0, WINDOW_WIDTH, ARENA_HEIGHT);
for(Iterator<Drawable> it = gameScene.models.iterator(); it.hasNext();)
{
Drawable d = it.next();
d.draw(g1);
}
Toolkit.getDefaultToolkit().sync();
}
and method draw of model in gameScene usually looks like this:
public void draw(Graphics g1){
Graphics2D g = (Graphics2D) g1.create();
int cx = image.getWidth(null) / 2;
int cy = image.getHeight(null) / 2;
g.rotate(rotation, cx+x, cy+y);
g.drawImage(image, x, y, null);
}
It looks like you haven't specifed a LayoutManager for your frame, so it will default to BorderLayout.
When you subsequently call frame.getContentPane().add(component) without passing in a position constant, the position BorderLayout.CENTER will be defaulted.
The result is that your GameView and BarView components will be rendered on top of each other.
As a quick test, try specifying the component position as follows:
GameView v = new GameView();
BarView bv = new BarView();
frame.getContentPane().add(bv, BorderLayout.LINE_START);
frame.getContentPane().add(v, BorderLayout.LINE_END);
Unless your UI is really simple, you'll probably find that you need to use some other layout manager. Refer to 'How to Use Various Layout Managers' for more on this subject.
I am working on a simple object drawing program using Swing in Java.
My program simply should draw shapes according to buttons when clicked, and move any shapes with the mouse. I have four buttons which draw rectangle, circle and square on screen. So far I did managed to draw to shapes when you click on buttons. but i want to move the shapes on screen which it did not work out.
The problem is this: When I click on circle shape to drag it around with mouse, it clears all the screen and noting is on the screen.
And, is there a way to clean all the screen when I click on clear button?
Thank you?
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class PaintProject extends JComponent implements ActionListener,
MouseMotionListener {
private int CircleX=0;
private int CircleY=0;
private int RectX=100;
private int RectY=100;
private int SquareX=300;
private int SquareY=200;
public static void main(String[] args) {
JFrame frame = new JFrame("NEW PAINT PROGRAME!");
JButton CircleButton = new JButton("Circle");
CircleButton.setActionCommand("Circle");
JButton RectangleButton = new JButton("Rectangle");
RectangleButton.setActionCommand("Rectangle");
JButton SquareButton = new JButton("Square");
SquareButton.setActionCommand("Square");
PaintProject paint = new PaintProject();
CircleButton.addActionListener(paint);
RectangleButton.addActionListener(paint);
SquareButton.addActionListener(paint);
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frame.setLayout(new FlowLayout());
frame.add(paint);
frame.add(CircleButton);
frame.add(RectangleButton);
frame.add(SquareButton);
frame.addMouseMotionListener(paint);
frame.pack();
frame.setVisible(true);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(500, 500);
}
private void drawCircle() {
Graphics g = this.getGraphics();
g.setColor(Color.red);
g.fillOval(CircleX, CircleY, 100, 100);
}
private void drawRectangle() {
Graphics g = this.getGraphics();
g.setColor(Color.green);
g.fillRect(RectX, RectY, 100, 300);
}
private void drawSquare() {
Graphics g = this.getGraphics();
g.setColor(Color.blue);
g.fillRect(SquareX, SquareY, 100, 100);
}
#Override
public void actionPerformed(ActionEvent e) {
String command = e.getActionCommand();
if (command.equals("Circle")) {
drawCircle();
}
else if (command.equals("Rectangle")) {
drawRectangle();
}
else if (command.equals("Square")) {
drawSquare();
}
}
#Override
public void mouseDragged(MouseEvent e) {
CircleX=e.getX();
CircleY=e.getY();
repaint();
}
}
As noted here and here, getGraphics() is not how to perform custom painting in Swing. Instead, override paintComponent() to render the desired content. It looks like you want to drag shapes using the mouse. A basic approach to moving a selected object is shown here; substitute your fillXxx() invocation for the drawString() shown there. For multiple shapes, use a List<Shape>; the clear command then becomes simply List::clear. A complete example is cited here; it features moveable, selectable, resizable, colored nodes connected by edges.
This a simple application I got from here this answer to How to set a Transparent Background of JPanel
that's supposed to explain how setOpaque() works.
public class TwoPanels {
public static void main(String[] args) {
JPanel p = new JPanel();
// setting layout to null so we can make panels overlap
p.setLayout(null);
CirclePanel topPanel = new CirclePanel();
// drawing should be in blue
topPanel.setForeground(Color.blue);
// background should be black, except it's not opaque, so
// background will not be drawn
topPanel.setBackground(Color.black);
// set opaque to false - background not drawn
topPanel.setOpaque(false);
topPanel.setBounds(50, 50, 100, 100);
// add topPanel - components paint in order added,
// so add topPanel first
p.add(topPanel);
CirclePanel bottomPanel = new CirclePanel();
// drawing in green
bottomPanel.setForeground(Color.green);
// background in cyan
bottomPanel.setBackground(Color.cyan);
// and it will show this time, because opaque is true
bottomPanel.setOpaque(true);
bottomPanel.setBounds(30, 30, 100, 100);
// add bottomPanel last...
p.add(bottomPanel);
// frame handling code...
JFrame f = new JFrame("Two Panels");
f.setContentPane(p);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setSize(300, 300);
f.setLocationRelativeTo(null);
f.setVisible(true);
}
// Panel with a circle drawn on it.
private static class CirclePanel extends JPanel {
// This is Swing, so override paint*Component* - not paint
protected void paintComponent(Graphics g) {
// call super.paintComponent to get default Swing
// painting behavior (opaque honored, etc.)
super.paintComponent(g);
int x = 10;
int y = 10;
int width = getWidth() - 20;
int height = getHeight() - 20;
g.fillArc(x, y, width, height, 0, 360);
}
}
}
The thing the I don't get is how come he is adding the opaque layer on top of transparent layer? shouldn't be the other way around?
The way that I picture how it should work is by adding the transparent layer on top of the opaque one, kinda of like how you put a screen protector over a phone(sorry for the dumb example)
Can someone please explain how transparency works in java?
I apologize of my question is a bit naive but this has been bothering me for a while!
Yes, the example reliest on the fact that with a null layout, the child components are indeed drawn in reverse order. An implementation dependency. That at least deserves mention. Adding a visible border would make it more evident:
private static class CirclePanel extends JPanel {
CirclePanel() {
setBorder(BorderFactory.createLineBorder(Color.RED));
}