LibGDX - 增量时间会导致精灵在曲线移动时有时表现得很奇怪

Question

所以我想出了如何在曲线中移动东西，当你有 3 个点时。 我以这样的曲线移动我的精灵：

以下代码在 render 方法中，该方法循环每个刻度。

if (ship.isMoving()){
// Normalized direction vector towards target
Vector2 dir = ship.getEndPoint().cpy().sub(ship.getLinearVector()).nor();
// Move towards target by adding direction vector multiplied by speed and delta time to linearVector
ship.getLinearVector().add(dir.scl(2 * Gdx.graphics.getDeltaTime()));
// calculate step based on progress towards target (0 -> 1)
float step = 1 - (ship.getEndPoint().dst(ship.getLinearVector()) / ship.getDistanceToEndPoint());
if (ship.getCurrentPerformingMove() != MoveType.FORWARD) {
// step on curve (0 -> 1), first bezier point, second bezier point, third bezier point, temporary vector for calculations
Bezier.quadratic(ship.getCurrentAnimationLocation(), step, ship.getStartPoint().cpy(),
ship.getInbetweenPoint().cpy(), ship.getEndPoint().cpy(), new Vector2());
}
else {
Bezier.quadratic(ship.getCurrentAnimationLocation(), step, ship.getStartPoint().cpy(),
new Vector2(ship.getStartPoint().x, ship.getEndPoint().y), ship.getEndPoint().cpy(), new Vector2());
}
// check if the step is reached to the end, and dispose the movement
if (step >= 0.99f) {
ship.setX(ship.getEndPoint().x);
ship.setY(ship.getEndPoint().y);
ship.setMoving(false);
System.out.println("ENDED MOVE AT  "+ ship.getX() + " " + ship.getY());
}
else {
// process move
ship.setX(ship.getCurrentAnimationLocation().x);
ship.setY(ship.getCurrentAnimationLocation().y);
}
// tick rotation of the ship image
if (System.currentTimeMillis() - ship.getLastAnimationUpdate() >= Vessel.ROTATION_TICK_DELAY) {
ship.tickRotation();
}
}

当我运行这个时，80% 的时间它运行平稳没有问题，但有时它会运行并且只是在 2 个动作之间有一些奇怪的滞后(如果我先做曲线然后做另一个曲线(，就像那里有什么我不明白的鱼

。我用错了增量吗？

Answer 1

正如@Tenfour04评论你的问题。可能是垃圾收集器启动并造成滞后。不要在更新/渲染循环中创建新对象。

// instance variable tmp
private Vector2 tmp = new Vector2();
// dir is now a reference to tmp no new objects allocated
Vector2 dir = this.tmp.set(ship.getEndPoint()).sub(ship.getLinearVector()).nor();
// the same thing with Bezier.quadratic equation
// only the currentAnimationLocation and tmp will be modified in the method
Bezier.quadratic(
ship.getCurrentAnimationLocation(), step, ship.getStartPoint(),
ship.getInbetweenPoint(), ship.getEndPoint(), this.tmp
);