zazza991
Junior Newbie
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Posted
2012-03-22 19:36:13 » |
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I seek an optimal algorithm to move via directional keys an image in a JFrame for a game. Someone knows how to help me? Thank you
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Eli Delventhal
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Reply #1 - Posted
2012-03-22 23:25:39 » |
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| public class MoveableImage { private float x, y; private Image image; public MoveableImage(Image i, float startX, float startY) { x = startX; y = startY; image = i; }
public void draw(Graphics g) { g.drawImage(image, (int)x, (int)y); }
public void moveTo(float newX, float newY) { x = newX; y = newY; }
public void moveBy(float deltaX, float deltaY) { x += deltaX; y += deltaY; } } |
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| MoveableImage image;
public void keyReleased(KeyEvent e) { int c = e.getKeyCode(); if (c == KeyEvent.VK_LEFT) { image.moveBy(-1.0f, 0.0f); } if (c == KeyEvent.VK_DOWN) { image.moveBy(0.0f, 1.0f); } } |
Clear enough? That's not optimal, but sounds like you're really far from optimal. When you're a lot more comfortable coding I'd put the moveBy's into a game loop instead of being called directly by the keyReleased function.
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zazza991
Junior Newbie
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Reply #2 - Posted
2012-03-22 23:32:08 » |
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Thank you. But if I keep the directional pad down the sprite will move quickly or slowly? to be clear I would like to create a super mario type platform
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Games published by our own members! Check 'em out!
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ra4king
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Reply #3 - Posted
2012-03-23 00:21:25 » |
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It's up to you to change those "moveBy" values in keyPressed to your liking 
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Eli Delventhal
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Reply #4 - Posted
2012-03-23 00:26:44 » |
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Yes. Also go read a programming book, because this all should be clear unless you're very inexperienced. No offense at all meant, by the way...
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ReBirth
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Reply #5 - Posted
2012-03-23 06:47:40 » |
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Clearly no offense. By learning how object is you can figure it out easily. Next you can do complex things by yourself.
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zazza991
Junior Newbie
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Reply #6 - Posted
2012-03-23 12:37:13 » |
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I studied several books and supported tests in java. My problem is that I want an equal movement in case you press or hold a button. For this reason I asked
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zazza991
Junior Newbie
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Reply #7 - Posted
2012-03-23 13:12:34 » |
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now place the code, maybe it's better 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192
| package Immagini;
import java.awt.BorderLayout; import java.awt.Dimension; import java.awt.Graphics; import java.awt.GridLayout; import java.awt.Image; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.KeyAdapter; import java.awt.event.KeyEvent; import java.io.File; import java.io.IOException;
import javax.imageio.ImageIO; import javax.swing.ImageIcon; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.Timer;
public class MovimentoFrame extends JFrame{ public static final int MILLISECONDI = 100; public static final int SPRITE_DIM = 32; public static final int COLONNE = 20; public static final int RIGHE = 20; public static final int APPLET_WIDTH = RIGHE*SPRITE_DIM; public static final int APPLET_HEIGHT = COLONNE*SPRITE_DIM; public static final int JUMP = SPRITE_DIM; private JLabel[] arraylabel; private ImageIcon imgPers; private JLabel labelPers; private JPanel jp; private boolean isControlled=true; private int x; private int y; private int inc_x; private int inc_y; private Timer timer; private Image image; private ImageIcon immagine; private ImageIcon imgTexture; public MovimentoFrame(int x0, int y0){ x=x0; y=y0; inc_x=inc_y=0; try { image = ImageIO.read(new File("/home/vincenzo/Scrivania/grass09.jpg")); } catch (IOException e) { e.printStackTrace(); } getContentPane().setLayout(null); getContentPane().setPreferredSize(new Dimension(APPLET_WIDTH, APPLET_HEIGHT)); imgPers = new ImageIcon("/home/vincenzo/Scrivania/persT.PNG"); labelPers = new JLabel(imgPers); labelPers.setBounds(0, 0, 32, 32); labelPers.setOpaque(false); jp = new BackgroundPanel(image); jp.setLayout(null); jp.setBounds(0, 0, APPLET_WIDTH, APPLET_HEIGHT); jp.add(labelPers); createImageIcon(); createPanelImage(); getContentPane().add(jp); addKeyListener(new DirectionKeyListener()); timer = new Timer(MILLISECONDI, new ActionListener() { public void actionPerformed(ActionEvent evt) { int x1 = x + inc_x; int y1 = y + inc_y; if ((x1>=0) && (x1<APPLET_WIDTH)) x=x1; if ((y1>=0) && (y1<APPLET_HEIGHT)) y=y1; aggiorna(); } }); } private class DirectionKeyListener extends KeyAdapter { public void keyPressed(KeyEvent event) { switch (event.getKeyCode()) { case KeyEvent.VK_UP: inc_y=-JUMP; isControlled=false; break; case KeyEvent.VK_DOWN: inc_y=JUMP; isControlled=false; break; case KeyEvent.VK_LEFT: inc_x=-JUMP; isControlled=false; break; case KeyEvent.VK_RIGHT: inc_x=JUMP; isControlled=false; break; default: break; } } public void keyReleased(KeyEvent event) { switch (event.getKeyCode()) { case KeyEvent.VK_UP: case KeyEvent.VK_DOWN: inc_y=0; break; case KeyEvent.VK_LEFT: case KeyEvent.VK_RIGHT: inc_x=0; break; } } } public void aggiorna() { labelPers.setBounds(x, y,32,32); if(!isControlled) controll(); repaint(); } public void controll(){ for(int i=0;i<RIGHE;i++) if(labelPers.getLocationOnScreen().equals(arraylabel[i].getLocationOnScreen())){ System.out.println(arraylabel[i].getX()+" "+arraylabel[i].getY()); break; } isControlled = true; } class BackgroundPanel extends JPanel { private Image img;
public BackgroundPanel (Image img) { super (new BorderLayout ()); this.img = img; }
public void paintComponent (Graphics g) { super.paintComponent (g);
g.drawImage (img, 0, 0, this); } } private void createImageIcon() { int i; int j; arraylabel = new JLabel[RIGHE]; imgTexture = new ImageIcon("/home/vincenzo/Scrivania/erbaTR.PNG"); for(i=0;i<RIGHE;i++){ arraylabel[i]= new JLabel(imgTexture); arraylabel[i].setSize(32,32); } } private void createPanelImage(){ for(int i=0;i<RIGHE;i++){ arraylabel[i].setBounds(i*JUMP, JUMP*5, 32, 32); jp.add(arraylabel[i]); } } public static void main(String[] args) { MovimentoFrame c= new MovimentoFrame(0,0); c.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); c.pack(); c.setResizable(false); c.setVisible(true); c.timer.start(); c.setLocationRelativeTo(null); System.out.println(c.getSize()); } } |
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Fokusas
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Reply #8 - Posted
2012-03-23 14:44:45 » |
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If this is real code then it has some grammatical mistakes and compiler shouldn't compile or run. Looks like you are missing some ; and break in some switch cases. Also there maybe some other problems that I don't see. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
| private class DirectionKeyListener extends KeyAdapter { public void keyReleased(KeyEvent event) { switch (event.getKeyCode()) { case KeyEvent.VK_UP: case KeyEvent.VK_DOWN: inc_y=0; break; case KeyEvent.VK_LEFT: case KeyEvent.VK_RIGHT: inc_x=0; break; } } } |
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zazza991
Junior Newbie
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Reply #9 - Posted
2012-03-23 15:04:06 » |
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Sorry but to me it always compiled this code, maybe you can give problems only because I do not find images why don't you have. There is some optimization that I can do for this code?
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teletubo
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Reply #10 - Posted
2012-03-23 15:06:46 » |
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If this is real code then it has some grammatical mistakes and compiler shouldn't compile or run. Looks like you are missing some ; and break in some switch cases. Also there maybe some other problems that I don't see. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
| private class DirectionKeyListener extends KeyAdapter { public void keyReleased(KeyEvent event) { switch (event.getKeyCode()) { case KeyEvent.VK_UP: case KeyEvent.VK_DOWN: inc_y=0; break; case KeyEvent.VK_LEFT: case KeyEvent.VK_RIGHT: inc_x=0; break; } } } |
I haven't fully read his code, but I see no syntatic problems here. You don't need to have a break for each case. @zazza: I highly recomend you checking some 4k skeletons. They're simple at most but you'll have a nice skeleton on drawing things in screen and treating keypresses, in the best ways available (and not using AWT, JLabels, ImageIcon which are definetely not meant to be used with games).
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zazza991
Junior Newbie
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Reply #11 - Posted
2012-03-23 15:10:45 » |
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thank the Council. I saw some skeletons 4 k at other times, but inside there were too many things that I didn't know
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Fokusas
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Reply #12 - Posted
2012-03-23 15:18:15 » |
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Well looks like my eyes deceive me. Because I only look at code but don't compiled it. But I think that you should put break after each case or don't make that case, because switch without breaks could execute unwanted code which don't belong to that case (or belong to other case). And I must admire to teletubo that awt, swing isn't made for games, but you can use it if you don't have anything better. (But mostly there is) If this is real code then it has some grammatical mistakes and compiler shouldn't compile or run. Looks like you are missing some ; and break in some switch cases. Also there maybe some other problems that I don't see. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
| private class DirectionKeyListener extends KeyAdapter { public void keyReleased(KeyEvent event) { switch (event.getKeyCode()) { case KeyEvent.VK_UP: case KeyEvent.VK_DOWN: inc_y=0; break; case KeyEvent.VK_LEFT: case KeyEvent.VK_RIGHT: inc_x=0; break; } } } |
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Mike
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Reply #13 - Posted
2012-03-23 15:51:44 » |
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But I think that you should put break after each case or don't make that case, because switch without breaks could execute unwanted code which don't belong to that case (or belong to other case)
switch!=if That function is clean and correct. Also, shouldn't this be placed in the newbie section?  Mike
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zazza991
Junior Newbie
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Reply #15 - Posted
2012-03-24 14:33:34 » |
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Guys I have modified my code through a 4k skeleton but I have the problem that my image moves too fast. Now place the code 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182
| package Gioco;
import java.applet.Applet; import java.awt.BorderLayout; import java.awt.Dimension; import java.awt.Graphics; import java.awt.Image; import java.awt.event.KeyEvent; import java.io.File; import java.io.IOException;
import javax.imageio.ImageIO; import javax.swing.ImageIcon; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.Timer;
public class Gioco extends Applet implements Runnable { private boolean[] keyPress = new boolean[32768]; private final int SPRITE_DIM = 32; private final int COLONNE = 20; private final int RIGHE = 20; private final int APPLET_WIDTH = RIGHE*SPRITE_DIM; private final int APPLET_HEIGHT = COLONNE*SPRITE_DIM; private final int JUMP = SPRITE_DIM; private JLabel[] arraylabel; private ImageIcon imgTexture; private JPanel jp; private Image image; public void start(){ enableEvents(8); new Thread(this).start(); } public void run(){ int playerX = 0; int playerY=0; final int VK_LEFT = 0x25; final int VK_RIGHT = 0x27; final int VK_UP = 0x26; final int VK_DOWN = 0x28; final int VK_ATTACK = 0x42; final int MILLISECONDI = 100; ImageIcon imgPers; JLabel labelPers; boolean isControlled=true; int x=0; int y=0; int inc_x; int inc_y; ImageIcon immagine; try { image = ImageIO.read(new File("C:/Users/vincenzo/Desktop/img/grass09.jpg")); } catch (IOException e1) { e1.printStackTrace(); } setLayout(null); setPreferredSize(new Dimension(APPLET_WIDTH, APPLET_HEIGHT)); imgPers = new ImageIcon("C:/Users/vincenzo/Desktop/img/persT.PNG"); labelPers = new JLabel(imgPers); labelPers.setBounds(0, 0, 32, 32); labelPers.setOpaque(false); jp = new BackgroundPanel(image); jp.setLayout(null); jp.setBounds(0, 0, APPLET_WIDTH, APPLET_HEIGHT); jp.add(labelPers); createImageIcon(); createPanelImage(); add(jp); long nextFrameStartTime = System.nanoTime(); while(true){ do{ nextFrameStartTime += 16666667; x = playerX; y = playerY; if (keyPress[VK_UP]) { y -= JUMP; } else if (keyPress[VK_DOWN]) { y += JUMP; } else if (keyPress[VK_LEFT]) { x -= JUMP; } else if (keyPress[VK_RIGHT]) { x += JUMP; } if ((x>=0) && (x<APPLET_WIDTH)) playerX=x; if ((y>=0) && (y<APPLET_HEIGHT)) playerY=y; }while(nextFrameStartTime < System.nanoTime()); labelPers.setBounds(playerX, playerY,32,32); while(nextFrameStartTime - System.nanoTime() > 0) { Thread.yield(); } } } public void processKeyEvent(KeyEvent keyEvent) { final int VK_LEFT = 0x25; final int VK_RIGHT = 0x27; final int VK_UP = 0x26; final int VK_DOWN = 0x28; final int VK_ATTACK = 0x42; final int VK_W = 0x57; final int VK_S = 0x53; final int VK_A = 0x41; final int VK_D = 0x44;
int k = keyEvent.getKeyCode(); if (k > 0) { k = k == VK_W ? VK_UP : k == VK_D ? VK_RIGHT : k == VK_A ? VK_LEFT : k == VK_S ? VK_DOWN : k; keyPress[(k >= VK_LEFT && k <= VK_DOWN) ? k : VK_ATTACK] = keyEvent.getID() != 402; } } private void createImageIcon() { int i; int j; arraylabel = new JLabel[RIGHE]; imgTexture = new ImageIcon("C:/Users/vincenzo/Desktop/img/erbaTR.PNG"); for(i=0;i<RIGHE;i++){ arraylabel[i]= new JLabel(imgTexture); arraylabel[i].setSize(32,32); } } private void createPanelImage(){ for(int i=0;i<RIGHE;i++){ arraylabel[i].setBounds(i*JUMP, JUMP*5, 32, 32); jp.add(arraylabel[i]); } } class BackgroundPanel extends JPanel { private Image img;
public BackgroundPanel (Image img) { super (new BorderLayout ()); this.img = img; }
public void paintComponent (Graphics g) { super.paintComponent (g);
g.drawImage (img, 0, 0, this); } } } |
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Fokusas
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Reply #16 - Posted
2012-03-24 14:59:27 » |
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But I think that you should put break after each case or don't make that case, because switch without breaks could execute unwanted code which don't belong to that case (or belong to other case)
switch!=if That function is clean and correct. Also, shouldn't this be placed in the newbie section?  Mike Well looks who's here  But i think that if you think that my post is wrong you are wrong! Switch without break is just a lines of code and no switch. Case without break is damned to execute all other following cases and code; P.S. No offence.
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sproingie
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Reply #17 - Posted
2012-03-24 17:47:11 » |
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Switch-case fall-through was properly used in this case, end of story.
You also really shouldn't reuse Java4K code other than for another Java4K project. Especially not to learn a new algorithm.
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ReBirth
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Reply #18 - Posted
2012-03-25 03:31:59 » |
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Nuff said, switch-case only makes my tall 'if' statement become beauty.
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Eli Delventhal
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Reply #19 - Posted
2012-03-26 22:52:56 » |
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Well looks who's here  But i think that if you think that my post is wrong you are wrong! Switch without break is just a lines of code and no switch. Case without break is damned to execute all other following cases and code; P.S. No offence. Will +1 what others have said, a drop-through switch case is totally fine. Perhaps what you are alluding to is a dropthrough case that has additional logic, which some view as bad practice (and it's not even valid in C#). But a flat dropthrough like that is fine everywhere. Also I will +1 not using the 4k example as 4k does a lot of bad practices to reduce memory usage. Instead check out Basic Game tutorial and Game Loops tutorial. But since you've already adapted the 4k skeleton just give it a go I suppose.
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