Question

所以当你有3分时，我想出了如何在曲线中移动东西。我将我的精灵移动成这样的曲线：

以下代码位于render方法中，它循环每个tick。

    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();
        }
    }

当我运行它时，80％的时间它没有问题顺利运行，但有时它会运行，并且在两个动作之间只有一些奇怪的延迟（如果我做第一个曲线然后是另一个曲线），就像是我在那里不明白。

我是否使用delta错误？

Answer 1

正如@ Tenfour04对您的问题发表了评论。可能是垃圾收集器开始并造成滞后。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
);

LibGDX - Delta时间导致精灵在曲线移动时有时会表现得很奇怪

1 个答案: