Wie man sprite-springen in java?

Dies ist das grundlegende Konzept. Ihre Umsetzung wird sich ändern, je nach der Implementierung Ihres Motors.

Die grundlegende Idee ist die Spieler eine vertikale delta, die verändert im Laufe der Zeit durch die Schwerkraft. Diese Effekte, die sprites vertikale Geschwindigkeit.

Diese Implementierung hat auch einen re-bound-delta, welches erlaubt die Sprites zu re-bound ist eher das "stoppen" plötzlich. Die re-gebunden ist, erfolgt durch eine re-bound-Abbau, die reduziert die Menge von re-bound-auf jeder neu gebunden.

Simuliert einen Spiel-Charakter, so dass Sie brauchen werden, um drücken Sie Raum, um es zu starten Prellen...

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import javax.swing.AbstractAction;
import javax.swing.ActionMap;
import javax.swing.InputMap;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class JumpingSprite {

    public static void main(String[] args) {
        new JumpingSprite();
    }

    public JumpingSprite() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JFrame frame = new JFrame("Test");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public static class TestPane extends JPanel {

        protected static final int SPRITE_HEIGHT = 10;
        protected static final int SPRITE_WIDTH = 10;
        private float vDelta; //The vertical detla...
        private float rbDelta; //Rebound delta...
        private float rbDegDelta; //The amount the rebound is degradation...
        private int yPos; //The vertical position...
        private float gDelta; //Gravity, how much the vDelta will be reduced by over time...
        private Timer engine;
        private boolean bounce = false;

        public TestPane() {

            yPos = getPreferredSize().height - SPRITE_HEIGHT;
            vDelta = 0;
            gDelta = 0.25f;
            //This is how much the re-bound will degrade on each cycle...
            rbDegDelta = 2.5f;

            InputMap im = getInputMap(WHEN_IN_FOCUSED_WINDOW);
            ActionMap am = getActionMap();
            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_SPACE, 0), "jump");
            am.put("jump", new AbstractAction() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    //Can only bound when we're actually on the ground...
                    //You might want to add fudge factor here so that the 
                    //sprite can be within a given number of pixels in order to
                    //jump again...
                    if (yPos + SPRITE_HEIGHT == getHeight()) {
                        vDelta = -8;
                        rbDelta = vDelta;
                        bounce = true;
                    }
                }
            });

            engine = new Timer(40, new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    int height = getHeight();
                    //No point if we've not been sized...
                    if (height > 0) {
                        //Are we bouncing...
                        if (bounce) {
                            //Add the vDelta to the yPos
                            //vDelta may be postive or negative, allowing
                            //for both up and down movement...
                            yPos += vDelta;
                            //Add the gravity to the vDelta, this will slow down
                            //the upward movement and speed up the downward movement...
                            //You may wish to place a max speed to this
                            vDelta += gDelta;
                            //If the sprite is not on the ground...
                            if (yPos + SPRITE_HEIGHT >= height) {
                                //Seat the sprite on the ground
                                yPos = height - SPRITE_HEIGHT;
                                //If the re-bound delta is 0 or more then we've stopped
                                //bouncing...
                                if (rbDelta >= 0) {
                                    //Stop bouncing...
                                    bounce = false;
                                } else {
                                    //Add the re-bound degregation delta to the re-bound delta
                                    rbDelta += rbDegDelta;
                                    //Set the vDelta...
                                    vDelta = rbDelta;
                                }
                            }
                        }
                    }
                    repaint();
                }
            });
            engine.start();
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(200, 200);
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2d = (Graphics2D) g.create();
            int width = getWidth() - 1;
            int xPos = (width - SPRITE_WIDTH) / 2;
            g2d.drawOval(xPos, yPos, SPRITE_WIDTH, SPRITE_HEIGHT);
            g2d.dispose();
        }
    }
}