LWJGL按住一键

Question

So basicaly what im trying to do is using LWJGL now making my player move in the game. The player is currently moving but he doesnt keep mooving while you are holding the button..

public void update(){ while(Keyboard.next()){

        if(Keyboard.getEventKey() == Keyboard.KEY_RIGHT) {
            if(Keyboard.getEventKeyState()){
                System.out.println("KEY DOWN!");
                player.playerMovingRight();
            }
            else{
                System.out.println("KEY RELEASED!");
            }
        }
    }

I tried using a while(Keyboard.getEventKeyState()) but it just made the game crash and it wouldnt recognise if i release the key.

So how can i make my player keep moving if you hold the button instead of having to rapidly press the key to move. And how would i make it work if the player is holding 2 buttons at the same time?

Updated code:

public void update(){
    while(Keyboard.next()){

        //If key escape is down we shut the application down
        if(Keyboard.isKeyDown(Keyboard.KEY_ESCAPE)){
            System.exit(0);
        }

        //If key up was pressed move up
        else if(Keyboard.getEventKey() == Keyboard.KEY_UP) {
            if(Keyboard.getEventKeyState()){
                System.out.println("KEY DOWN!");
                moveUp = true;
            }
            else{
                System.out.println("KEY RELEASED!");
                moveUp = false;
            }
        }
        //If key down was pressed move down
        else if(Keyboard.getEventKey() == Keyboard.KEY_DOWN) {
            if(Keyboard.getEventKeyState()){
                System.out.println("KEY DOWN!");
                moveDown = true;
            }
            else{
                System.out.println("KEY RELEASED!");
                moveDown = false;
            }
        }

        if(moveUp == true){
            player.playerMovingUp();
        }
        if(moveDown == true){
            player.playerMovingDown();
        }
    }

Im still having the same problem with the code, Im starting to think its they Keyboard.next() that is preventing me from holding the button and the player still moves.

Answer 1

What you need is a boolean flag which triggers when the button is pressed down, and is untriggered when the button is released. The flag would then be added to an if statement before the movement code. Like so:

if(Keyboard.getEventKey() == Keyboard.KEY_RIGHT) {
        if(Keyboard.getEventKeyState()){
            System.out.println("KEY DOWN!");
            flag = true;       
        }
        else{
            System.out.println("KEY RELEASED!");
            flag = false;
        }
    }
}

//player movement code

if(flag) {
    player.playerMovingRight();
}

The way to do it with multiple keys is to use an array of boolean triggers and repeating the checks for each key.

Answer 2

While the above answer will work, LWJGL has the capability to detect if a key is being held down. It is not enabled by default though, so you need to enable it. To do this just set this flag to true somewhere in your input initialization.

Keyboard.enableRepeatEvents(true);

Now in your event loop, just do this check on your keys to see if it is a repeat (held down key).

if(Keyboard.isRepeatEvent())

Here is a small sample to see how to check a key for different key states.

while(Keyboard.next())
    {
        if(Keyboard.getEventKey() == Keyboard.KEY_A)
            if(Keyboard.getEventKeyState())
            {
                if(Keyboard.isRepeatEvent())
                    // Key held down
                else
                    // Key pressed
            }
            else
                // Key released
    }

Answer 3

while(Keyboard.next()) is supposed to be used with events.

In your case, you don't want to only do something, when an event gets triggered. But you want to determine many times per second, whether a key is pressed or not. If it is, you want to do something (eg move).

So it's the best solution to use the Keyboard.isKeyDown() function. A little example:

if (Keyboard.isKeyDown(Keyboard.KEY_UP)) {
    System.out.println("pressing KEY_UP");
}
if (Keyboard.isKeyDown(Keyboard.KEY_DOWN)) {
    System.out.println("pressing KEY_DOWN");
}
if (Keyboard.isKeyDown(Keyboard.KEY_LEFT)) {
    System.out.println("pressing KEY_LEFT");
}
if (Keyboard.isKeyDown(Keyboard.KEY_RIGHT)) {
    System.out.println("pressing KEY_RIGHT");
}

Also, a good tutorial can be found here .