如何在Libgdx中跟踪多个触摸事件？ [英] How to track multiple touch events in Libgdx?

问题描述

我正在使用Libgdx制作赛车游戏。我想触摸屏幕的右半边以加快速度，同时在不移除先前触摸点的情况下再次触摸屏幕左侧的另一个触发点。我无法检测到以后的触摸点。

I am making a racing game using Libgdx. I want to touch the half right side of screen to speed up, at the same time without removing previous touch point touch again another on the left side of the screen to fire a shot. I am unable to detect later touch points.

我搜索并获得 Gdx.input.isTouched（int index）方法，但无法确定如何使用它。我的屏幕触摸代码是：

I have searched and get Gdx.input.isTouched(int index) method, but cannot determin how to use it. My screen touch code is:

if(Gdx.input.isTouched(0) && world.heroCar.state != HeroCar.HERO_STATE_HIT){
    guiCam.unproject(touchPoint.set(Gdx.input.getX(), Gdx.input.getY(), 0));
    if (OverlapTester.pointInRectangle(rightScreenBounds, touchPoint.x, touchPoint.y)) {
       world.heroCar.state = HeroCar.HERO_STATE_FASTRUN;
       world.heroCar.velocity.y = HeroCar.HERO_STATE_FASTRUN_VELOCITY;
    }
} else {
    world.heroCar.velocity.y = HeroCar.HERO_RUN_VELOCITY;
}

if (Gdx.input.isTouched(1)) {
    guiCam.unproject(touchPoint.set(Gdx.input.getX(), Gdx.input.getY(), 0));
    if (OverlapTester.pointInRectangle(leftScreenBounds, touchPoint.x, touchPoint.y)) {
       world.shot();
    }
}

推荐答案

你我想使用 Gdx.input.getX（int index） 方法。整数 index 参数表示活动指针的ID。要正确使用它，你需要遍历所有可能的指针（如果两个人在平板电脑上有20个手指？）。

You'll want to use the Gdx.input.getX(int index) method. The integer index parameter represents the ID of an active pointer. To correctly use this, you will want to iterate through all the possible pointers (in case two people have 20 fingers on the tablet?).

这样的事情：

boolean fire = false;
boolean fast = false;
final int fireAreaMax = 120; // This should be scaled to the size of the screen?
final int fastAreaMin = Gdx.graphics.getWidth() - 120;
for (int i = 0; i < 20; i++) { // 20 is max number of touch points
   if (Gdx.input.isTouched(i)) {
      final int iX = Gdx.input.getX(i);
      fire = fire || (iX < fireAreaMax); // Touch coordinates are in screen space
      fast = fast || (iX > fastAreaMin);
   }
}

if (fast) {
   // speed things up
} else {
   // slow things down
}

if (fire) {
   // Fire!
}

另一种方法是设置 InputProcessor 获取输入事件（而不是轮询 输入如上例所示。当指针进入其中一个区域时，您必须跟踪该指针的状态（如果它离开，您可以清除它）。

An alternative approach is to setup an InputProcessor to get input events (instead of "polling" the input as the above example). And when a pointer enters one of the areas, you would have to track that pointer's state (so you could clear it if it left).

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