I've been trying to make gun plugin for Bukkit, and I'm trying to build a burst fire feature. I have a for loop that contains a delayed task, and inside that delayed task is the code to create a bullet and all that. Theoretically, the code would add some bullets, wait one tick, and add some more bullets, wait one tick, etc until the for loop is done.
public void fire(final Player p, final Gun g) {
for(int i=0; i<shotsPerBurst; i++) {
Bukkit.getServer().getScheduler().scheduleAsyncDelayedTask(plugin, new Runnable() {
public void run() {
for(int i=0; i<bulletsPerShot; i++) {
Bullet b = new Bullet(p, g);
GunsV1.bullets.add(b);
}
}
}, 1L);
}
}
Eclipse demands that Player p and Gun g both be final, I don't know why, and when I try to run fire(p, g), nothing happens. How can I set up my code so the for loop will run with a delay of 1 tick between cycles?
To resolve one question:
Eclipse demands that Player p and Gun g both be final, I don't know why
You are passing the Player p and the Gun g to an new Thread/new Runnable and Eclipse tells you that those 2 Object's shouldn't be modified or changed because the Thread/Runnable also uses these 2 Object's inside the run method (as you can see).
I would suggest you to write your issue directly in here: http://bukkit.org/forums/plugin-development.5/ because there are also developer which know more and in detail about the Bukkit Server for Minecraft.
I will try to find a solution that fit's your needs now - but maybe you already try to find a solution in the forum.
Found this link for you - it may help you a little bit: http://www.programcreek.com/java-api-examples/index.php?api=org.bukkit.scheduler.BukkitScheduler
There's no easy way to run the for loop with a delay without freezing Bukkit's main thread. The best thing to do in this case is to use plugin.getServer().getScheduler().runTaskLater():
plugin.getServer().getScheduler().runTaskLater(plugin, new Runnable(){
public void run(){
//shoot the gun
}
},1L);//run after 1 tick
But, if you use this, the gun will only fire one shot. To fix this, you should keep running the scheduler:
public static void runTask(){
plugin.getServer().getScheduler().runTaskLater(plugin, new Runnable(){
public void run(){
//shoot the gun
runTask(); //run the task again
}
},1L);//run after 1 tick
}
But this way, the gun will keep firing every tick, and never stop. So, you should count the number of times it has ran, and stop running the task once the number is reached:
public static void runTask(final int timesLeft){
plugin.getServer().getScheduler().runTaskLater(plugin, new Runnable(){
public void run(){
//shoot the gun
if(timesLeft > 0){
runTask(timesLeft - 1); //run the task again after removing from the times left
}
}
},1L);//run after 1 tick
}
So, in the end, your loop method could look something like this:
public static void fire(final Player player, final Gun gun, final int timesLeft){
plugin.getServer().getScheduler().runTaskLater(plugin, new Runnable(){
public void run(){
Bullet bullet = new Bullet(player, gun);
GunsV1.bullets.add(bullet);
if(timesLeft > 0){
fire(player, gun, timesLeft - 1); //run the task again after removing from the times left
}
}
},1L);//run after 1 tick
}
and you could call it by using:
fire(player, gun, shotsPerBurst);
After experimenting with some longer delays and looking at the spigot reference, I realized that the ticks of delay are not ticks until the next task, but until the runnable runs. Knowing this, I was able to use the for loop to increase the ticks of delay proportionally:
public void fire(final Player p, final Gun g) {
for(int i=0; i<shotsPerBurst; i++) {
Bukkit.getServer().getScheduler().scheduleSyncDelayedTask(plugin, new Runnable() {
public void run() {
for(int i=0; i<bulletsPerShot; i++) {
Bullet b = new Bullet(p, g);
GunsV1.bullets.add(b);
}
}
}, i*3);
}
}
Now it runs each task three ticks after the previous one, and fires in a burst
Related
Ok so i'm going to try to explain this, well I created a shoot method in a class that contains my bluespell, and all of it's constructors, well the problem is when I press space once it constantly shoots without me pressing it again, and if I press it twice the speed at which it fires doubles and it starts to contain more than one x and y position on my grid I just want the spell to fire when fired and I only need one item because I don't want there to be more than one instance of it on the grid I want it to be that the player cannot fire until the spell has left the grid, here's my code thanks oh and I only have it called in my key released seeing as it should only do it once the key has been released, but if that should change please let me know thanks :)
public void shootSpell(){
final BlueSpell b = new BlueSpell(GoodGuy.getx(), GoodGuy.gety() +1, BlueSpellWizard());
int delay = 100;
ActionListener taskPerformed = new ActionListener(){
public void actionPerformed(ActionEvent e){
if(b.gety() != 19){
WizardCells[b.getx()][b.gety()].setIcon(null);
WizardCells[b.getx()][b.changey(b.gety()+1)].setIcon(b.getIcon());
}
else{
WizardCells[b.getx()][b.gety()].setIcon(null);
b.changex(GoodGuy.getx());
b.changey(GoodGuy.gety() +1);
}
}
};
new Timer(delay, taskPerformed).start();
else if(key == KeyEvent.VK_SPACE){
GoodSpell.shootSpell();
}
Do not use a Timer! Your task should not repeat every 100 milliseconds. If I understand your code, you should run the code from your ActionListener in a new thread.
// Something like this,
new Thread(new Runnable() {
public void run() {
if (b.gety() != 19) {
WizardCells[b.getx()][b.gety()].setIcon(null);
WizardCells[b.getx()][b.changey(b.gety() + 1)].setIcon(b
.getIcon());
} else {
WizardCells[b.getx()][b.gety()].setIcon(null);
b.changex(GoodGuy.getx());
b.changey(GoodGuy.gety() + 1);
}
}
}).start();
You also need to do a check if the spell is currently in view/activate prior to initiating a new spell in the shoot() method...
public void shootSpell(){
//do a check here if a spell is already running!
final BlueSpell b = new BlueSpell(GoodGuy.getx(), GoodGuy.gety() +1, BlueSpellWizard());
int delay = 100;
//......
So in your method that is updating the spell going accross the screen you either need to have a flag in there if its still active, or if you are running it in a new thread, save that thread to a global var and check to see if the thread is running prior instantiating a new BlueSpell()
I'm having a problem I'm making a pool game and I need the ballos to react when I simulate a hit, the program works like this, you click the direction and power to hit the ball and the click go, the go button is in the GUI class where my labels are created, the button calls a method from my main class that recieves the parameter and then with a while in it, changes the X and Y of the ball till the power is reduced to 0 and then stops, the code is working, but the ball moves until the while stops. So the while works and when the power int is 0 the while goes out and then the new X,Y are painted.
This is the funcion that the button calls, the button sends all the parameters
public void golpe(int pbola, int pvelocidad, String pdireccion, JLabel[] listalabels) throws InterruptedException{
listabolas[pbola].setVelocidad(pvelocidad);
listabolas[pbola].setDireccion(pdireccion);
while (listabolas[pbola].getVelocidad() > 0) {
moverBola(pbola, listalabels);
//System.out.println(listabolas[pbola].getPosX());
//System.out.println(listabolas[pbola].getPosY());
Thread.sleep(500);
//This line is supposed to change the X and Y of the object over and over
//but only does it till the end
listalabels[pbola].setLocation(listabolas[pbola].getPosX(), listabolas[pbola].getPosY());
}
}
Here is the function moverbola(), only copied one "if" so that the code doesn't look to big
private void moverBola(int pbola, JLabel[] listalabels) {
if (listabolas[pbola].getDireccion().equals("SE")) {
int pposX = listabolas[pbola].getPosX();
listabolas[pbola].setPosX(pposX + 1);
int pposY = listabolas[pbola].getPosY();
listabolas[pbola].setPosY(pposY + 1);
}
Swing is a single threaded framework. That is, all interactions with UI are expected to occur from within a single thread, known as the Event Dispatching Thread.
Any action that blocks this thread, will prevent the EDT from updating the screen or processing any new events.
Your while-loop is blocking the EDT, preventing it from painting any updates until after the while-loop is completed.
Take a look at Concurrency in Swing for more details.
There are a number of approaches you could take...
You could use a Thread, but this causes problems as you need to ensure that any changes you make to the UI are re-synced back to the EDT and this can become messy...
For example
You could use a javax.swing.Timer that ticks at a regular interval and you would update any internal parameters from within it's assigned ActionListener. Because the tick events occur within the EDT, it is save to update the screen from within it.
For example
You could use a SwingWorker to run the task in the background. It has methods for re-syncing updates back to the EDT, but might be a little over kill for your purposes...
Updated with a possible Timer example
Caveat- It is very hard to produce a reasonable example with only a code snippet, but, something like this might work
public void golpe(final int pbola, int pvelocidad, String pdireccion, final JLabel[] listalabels) throws InterruptedException{
listabolas[pbola].setVelocidad(pvelocidad);
listabolas[pbola].setDireccion(pdireccion);
Timer timer = new Timer(40, new ActionListener() {
public void actionPerformed(ActionEvent evt) {
if (listabolas[pbola].getVelocidad() == 0) {
((Timer)evt.getSource()).stop();
} else {
moverBola(pbola, listalabels);
}
}
});
timer.setRepeats(true);
timer.start();
}
Right now I'm working on a sort of space-invaders style game. You move the character to the y coordinate where the enemy is, and shoot.
There is four windows that the player will shoot at. There will ALWAYS be an enemy in one of them.
So here is how the code would work:
enemylocation = 1;
*CHANGE VALUE EVERY X SECONDS
if(enemylocation==1){
enemy.draw(x, y, size);
}
if(enemylocation==2){
enemy.draw(x, y, size);
}
if(enemylocation==3){
enemy.draw(x, y, size);
}
if(enemylocation==4){
enemy.draw(x, y, size);
}
What would the timing code/method be?
Thanks
You would want to use something like this:
public static void main(String[] args) throws InterruptedException
{
while(true) //Makes the code run forever
{
enemylocation++; // increments 1
Thread.sleep(1000); // Waits one second
}
}
Most people would use a Swing timer to update code over a given time interval. I would use the java.Math.Random Class to change the number to 1-4.
public class game implements ActionListener{
Timer enemyUpdate;
int enemylocation;
public game(){
enemyUpdate = new Timer(1000, this); //1000ms = 1s
enemyUpdate.start();
}
public void actionPerformed(){
//utilize math.random to change enemylocation every second
}
}
I am programming a chess game in java, and at the moment I am building a basic interface. It is simply an 8x8 array of buttons that will display in a window. I have coded for these buttons, and have gotten the board to display properly. However, when I connect this with the rest of the game, the game window crashes upon running and I have to force quit the java application. This is my code:
package Chess_Game;
import javax.swing.SwingUtilities;
import Chess_Interface.Iboard;
public class Game_Tester
{
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
Game G = new Game();
Iboard I = new Iboard(G.getBoard().getArray(), G.getSides());
I.setVisible(true);
while(!(G.isGameOver()))
{
boolean redo = true;
while(redo)
{
int row = 0;
int col = 0;
int nRow = 0;
int nCol = 0;
System.out.println("Click the piece you want to move.");
while(!(I.getBool())){}
if(I.getBool())
{
row = I.getRow();
col = I.getCol();
I.setBool(false);
}
System.out.println("Click the place you want to move to.");
while(!(I.getBool())){}
if(I.getBool())
{
nRow = I.getRow();
nCol = I.getCol();
I.setBool(false);
}
if(G.canMove(row, col, nRow, nCol))
{
G.move(row, col, nRow, nCol, I);
redo = false;
}
else
{
System.out.println("You cant move there! Try again!");
}
}
I.updateBoard(G.getBoard().getArray(), G.getSides());
}
}
});
}
}
The board displays properly when I comment out the main while loop (and everything inside of it), and I assume the problem lies somewhere inside there, but I have been unable to find it. I have also looked online for similar game loop problems, but all of those have been for games involving frame rates and movement across a java swing frame, something that is not present in my code.
Any help would be greatly appreciated.
You have several loops such as
while(!(I.getBool())){}
which could potentially run forever if I does not respond as expected. You could start by printing something out within these loops, and within the following blocks if(I.getBool()){...} to see at what point your application gets stuck.
Checking the user interface in a loop like this is not good practice. It is better to use Listeners to respond to the user interface.
Nor is running the main application on the Swing thread using SwingUtilities.invokeLater(new Runnable(), even though it avoids potential problems of updating the GUI from another thread.
In fact, this may be your root problem, as running the main application loop on the Swing thread (the thread used to run the GUI) like this probably prevents the GUI from ever responding properly. You are putting a task (the entire game) onto the GUI's queue, but that task never completes while(!(G.isGameOver())).
I am making a Conway's Game of Life program in java, and am trying to change it from the command line version to a GUI. From the command line I just printed an array which showed the generations (the objects such as blocks and blinkers are shown as a series of 1's and 0's where it is blank, and in the GUI I'm showing it as squares (white squares as blank and blue squares where it isn't). But where I'm getting stuck is when I make another method (which replaces the method which prints the array) which checks the grid array, if there is a zero then the square changes from white to blue, and vice-versa. The Conway's Life rules are dealt with in a separate class which is independent, and all this method does is after the rules have changed the array this method checks it.
The rules are done in methods in one class and the GUI components are done in another. But since I need instance of both how would I go about doing it?, merge the two classes (all the GUI classes into the Life one, embed them some how, I am completely stuck on what to do
public void runGUI() {
int x = getX(), y = getY();
x /= squareSize;
y /= squareSize;
for (int i = 0; i < LifeData.grid.length; i++) {
for (int j = 0; j < LifeData.grid[i].length; j++) {
if (LifeData.grid[i][j] == 0)
l.setCell(x, y, l.getCell(x, y) + 1);
else
l.setCell(x, y, l.getCell(x, y) - 1);
this.repaint();
}
}
}
That is what I have changed it to now but when compiling it is saying "non-static variable grid cannot be referenced from a static context" and "non-static method runGUI() cannot be referenced from a static context". When trying to run the method.
Make a separate thread that will execute the game of life and update the GUI.
Something like this
public class GameExecutor implements Runnable {
private static final int DELAY = 1000;
private GameOfLife game;
private boolean stop = false;
private Gui gui;
public GameExecutor(Gui gui, GameOfLife game) {
this.gui = gui;
this.game = game;
};
public void run(){
game.start();
while (!stop) {
game.step(); //execute a step
gui.update(game.getState());
try {
Thread.sleep(DELAY);
} catch (InterruptedException e) {}
}
}
}
Launch this in a thread at startup and pass it your gui. Don't forget to update the gui in the correct Swing thread.
Obviously you'll need to add some code to stop it, too :)