I need to add time delay between cycle flow like this:
public boolean timeDelay(int seconds) {
// 1000000000 ns = 1 s
if (/* some system method to start calculate time in seconds*/ == seconds) {
return true;
} else {
return false;
}
}
public void renderEnemies() {
for (int w = 0; w < wave.size(); w++) {
while(timeDelay(2)){
(wave.get(w)).render();
}
}
}
Maybe my thinking isn't good, but I need to do like this...
wave --> ArrayList of enemies in my game
Render enemies is in game loop after pressing button "NextWave" and I need to spawn them with delay between them like a --> 2s * 2s * 2s * 2s * 2s *
where * is enemy...
Can you help me?
Try:
Thread.sleep(1000);
and use a try-catch.
You should probably thread it and use sleep as #curiosu mentions.
However, if you don't want to use sleeps/multiple threads but do want it to be pseudo real time (not turn based) you'll need a driving loop at the top of your game like so:
boolean keepPlaying = true;
while(keepPlaying) {
doNpcStep()
doPlayerStep()
keepPlaying = !isGameOver()
}
Each of these steps needs to run in a very small time slice, then in the doNpcStep function you get the current time, find the offset from a start time and run any action that should happen by now.
You could, for example, do this by keeping a min priority queue where priority is equal to the time they should execute by (in ms since start of java epoch). Then take all elements off the queue that are less than or equal to current time and run them, placing new occurrences onto the queue as necessary.
In essence this is a simulation of running a player and npc thread, where you are in charge of how much time each gets to run for.
try putting an infinite while loop
while(1)
{
if(/*method to calc time*/ == seconds)
return true;
}
return false;
I'm assuming that you want to start spawning enemies after 'seconds' time, so always a 'true' should be returned after 'seconds' time has passed. Your method should keep track from what time it has to start counting the seconds. You can call that function when 'NextWave' button is pressed where a variable can increment itself in multiples of 'seconds' so that you can keep track of elapsed time.
Hope this helps.
Related
I'm new to java and I'm trying to constantly add "zombie" entity to my game after a delay, and then shortening the delay as time goes on.
In my PlayState class I've got the code to spawn the entities in a position when my update(); method is run (which houses getInput(); and such. Not shown for clarity.)
public void update(long elapsed) {
this.entities.add(new Zombie(-535));
}
How would i make a delay that shortens? I'm guessing I would make the delay and then use a multiplier which i have getting smaller every 10 seconds or so, but how would I do this?
Now, I don't know much about the finer workings of your class, but this might give you a general idea of what I mean:
int counter = 50;
for(int i = 100; i >= 0; i--)
{
if(i == counter)
{
counter = counter / 2;
this.entities.add(new Zombie(-535));
}
}
Suppose i is the the total run-time of the game, and counter represents a percent of the game when you want to add a zombie.
If you want to add a zombie after 50% of the run-time (here, 100 seconds), then as the time reduces, you check if the time has come to add a zombie (Here, 50 seconds).
What I've done here is reduce the delay to half, and continue checking if the time has come to add a zombie.
Maybe you could call sleep on your thread of execution:
int sleepInMs = 5000
Thread.sleep(sleepInMs);
sleepInMs+=1000; //Then of course handle the case when sleepInMs == 0
Really need more information about your implementation.
For a simple delay, use "delay ms;"
Edit ms for the number of milliseconds you want. 1000 milliseconds is one second
I am using LibGdx to develop an android game . I have implemented the gesture listener class in my InputHandler class . Now in the tap method I have to implement two features , short jump and long jump on single tap and double tap respectively. When I try to implement it using the count value of the function , the problem is when I double tap the screen the count value firstly becomes 1 and then 2 so it does not go into the second if statement and and the feature of short jump occurs. So how to differentiate single jump from double jump? Below is the code
#Override
public boolean tap(float x, float y, int count, int button) {
// TODO Auto-generated method stub
if(count==1)
{
//feature 1
}
if(count==2)
{
//feature 2
}
return true;
}
two solutions comes to my mind:
Use delay technique which would come with following steps:
when tap-count is 2 : trigger action for double tap
when tap-count is 1 : wait some time, if not tapped second time trigger action for single tap
code would be something like:
if(count==1)
{
if(wait) //wait is a boolean tells if it was tapped once already
{
if(getCurrentTime() - startTime > interval) //getCurrentTime() return current time or frame count or something
{
wait = false;
//feature 1
}
}
else
{
wait = true;
startTime = getCurrentTime(); //start time keeps the time when tapped first one
}
}
if(count==2)
{
//feature 2
}
return true;
}
the problem I see here is firstly "how to choose long enough interval for waiting for secon tap?" - if you will choose to short it will be impossible to make double tap, if too long there will be a lag and user will see that the character is not jumping directly after tap
Divide jump for a pieces and trigger them depends on tap count
And it depends on your "jumping" mechanism. If it be something like:
A. add force to jump
B. keep adding some force for some time to keep object in the air
C. avoid adding force to take object down back to ground
you could modify time to keep object in the air longer. If your "jumping mechanism" is more like impuls adding force (in upper example it would be variant without B point) you could add the force in A again for a some time and if user tapped second time before this interval ends keep on adding it just longer.
This solution eliminates lag problem but depends on "jumping mechanism" you choose.
Regards,
Michał
Recently, I've been getting into Java Game programming. I have learned Java before, but this is my first time with Graphics, Game Loops etc.
I followed this tutorial for a Game Loop, and it's working pretty well.
There is nothing wrong with it, but I just can't figure out why I am thread.sleeping the code, and whats the point of it.
If anyone could explain what start, elapsed and running do, and why I am doing thread.sleep(wait) then I would be super appreciative!
GAME LOOP (Remember, it works, I just don't know why):
while (running) {
start = System.nanoTime();
update();
draw();
drawToScreen();
elapsed = System.nanoTime() - start;
wait = targetTime - elapsed / 1000000;
if (wait < 0) {
wait = 5;
}
try {
Thread.sleep(wait);
} catch (Exception e) {
Game.logger.log("ERROR! Printing Stacktrace...");
e.printStackTrace();
}
}
}
Well, running is a flag that can be set to false to terminate the game.
start and elapsed are used to measure the time one round in the loop took. You are waiting to not make the game run too fast. If you are moving elements with a set speed, then having the game loop run too fast makes them also move too fast. That can lead to a bad user experience, since the user might not be fast enough to play the game.
Additionally, any animation doesn't run smooth anymore without the waiting. It will speed up and slow down depending on how fast your code executes.
Just continue with the tutorial, and when are at the point where you make something move, remove the waiting and see what happens.
EDIT
The code makes a round in the loop take about targetTime. It's unit is milliseconds. So to calculate the frame rate, just divide 1000 / targetTime.
start is the time before the game logic runs. elapsed is the amount of time that it takes for the game logic to run. running is a boolean (true/false) variable that determines whether the game should continue. Thread.sleep(wait) is a method that delays for a certain amount of time.
The goal is to keep the amount of time between frames roughly constant by delaying, so that the animations don't run faster or slower depending on how fast your computer processor is running.
It appears the code aims to be executed targetTime seconds. So you count how much time has already passed (elapsed), and then calculate how much to wait (divide it to get your remaining time in miliseconds, required for methon sleep(wait)).
One purpose of such waiting is often forcing some time between repainting to the screen.
To get your FPS, one way would be to slightly change your code:
long prevStart = 0; //just initialize. First FPS is of course wrong, next get fine.
double FPS = 0;
while (running) {
start = System.nanoTime();
FPS = 1 / double(start - prevStart);
prevStart = start;
update();
draw();
drawToScreen();
elapsed = System.nanoTime() - start;
wait = targetTime - elapsed / 1000000;
if (wait < 0) {
wait = 5;
}
try {
Thread.sleep(wait);
} catch (Exception e) {
Game.logger.log("ERROR! Printing Stacktrace...");
e.printStackTrace();
}
}
i have a game(like super jumper, this game is a jumping game) that our character has life. after collision with enemies, his life reduce. and i want to after 1 sec , calculate the collisions. i mean in this 1 sec, if my character contact with enemies , nothing happen and he continue his way.
for this , i define a boolean variable in my GameScreen class, name "collision" and another in Wolrd class, name "collBirds". after one contact with enemy collision and collBirds change to true. but i want after 1 sec collistion change to false. i use several things like System.currentTimeMillis() and "for loop",and nothing happen. i'm not so good in java.
this is my condition:
if(World.collBirds == true && collition == false){
life -= 1;
lifeString = "Life : " + life;
World.collBirds = false;
collition = true;
for (??? "need to stay here for 1 sec" ???) {
collition = false;
}
}
In some cases you could also want to use com.badlogic.gdx.utils.Timer
Example usage:
float delay = 1; // seconds
Timer.schedule(new Task(){
#Override
public void run() {
// Do your work
}
}, delay);
When the first collision occurs, set a float timeSinceCollision = 0;
Then each loop, you will need to add the time since last check to the variable, and check if it's more than a second.
timeSinceCollision += deltaTime;
if(timeSinceCollision > 1.0f) {
// do collision stuff
} else {
// ignore the collision
}
If you want to do this in same thread than you can use Thread.sleep(). But in this case your current thread will freeze and if this is single thread game, than your whole game will freeze. If you don't want your game to freeze for 1 second, than you should spawn the thread and in that thread call the sleep and after sleep, change the flag
As the question says, here's the code.
What I want to do basically is I have a list of array, says "myArray". This array contains stored time points in millisecond. Next thing is I want to call a method based on those time points. So, I need to run a time counter from 0 while the music is playing, compare the time counter with the time points in the array progressively (from first array index until finished).
The first method "timeCounter" is a method to start a time counter while a music is playing through MediaPlayer.
public void timeCounter(){
Runnable myRunnable = new Runnable(){
#Override
public void run(){
while(musicPlaying){
startCounter(arrayPos);
}
}
};
Thread musicPlayer = new Thread(myRunnable);
musicPlayer.start();
}
This is where the comparison of time counter and time in the array takes place.
public void startCounter(List<Long> array){
elapsedTime = System.currentTimeMillis() - timeStart;
if(elapsedTime == array.get(arrayPos)){
arrayPos += 1; //Continue comparing with the next number in the array
Log.v("DEBUG", "TIME MATCHES!");
if(arrayPos>= array.size()){
arrayPos= 0; //Prevent out of array index
}
}
}
I have the code running correctly and the result from the LogCat is correct.
Now the problem is sometimes the Thread is not running until the music finished playing (I have set onCompletionListener and set "musicPlaying" to false when music finished). The stopping point is totally random, sometimes when it's just started, or around 50%, or even when it's near to completion. Sometimes it doesn't even start!
I've been trying to figure out why but I couldn't find any info about Thread stopping halfway or such in anywhere. Thanks in advance! =)
If musicPlaying is modified and read between threads, make sure it is declared volatile.
I suspect your if(elapsedTime == array.get(arrayPos)) should be if(elapsedTime >= array.get(arrayPos)).
You need to remember that the millisecond timer does not necessarily have a one millisecond tick. On Windows, for example, the returned value will only change every 15 ms or so. You may therefore completely miss a particular time and therefore never get past that entry in your list.