恒定的Box2D体移动到在某一时刻 [英] Constant box2d body moving to point at a time

问题描述

我Box2D的身体在同一时间（定速）移动从（0,0）这个机构（100,100），它可以。怎么可能？我想这code：this.body.setLinearVelocity（新Vector2（1,0））;但它正在不停。

I have box2d body in Andengine.I wanna move this body from (0,0) to (100,100) at a time(constant speed).How can it be possible? I tried this code: this.body.setLinearVelocity(new Vector2(1, 0)); but it is moving non-stop.

推荐答案

我想沿着pdefined路径$ P $ Body.setTransform（...）移动是使用最简单的方法。这样，我们基本上忽略所有的力，摩擦，扭矩，碰撞等，并直接设置体的位置。

I guess the easiest way to move along a predefined path would be to use Body.setTransform(...). This way we basically ignore all forces, friction, torque, collisions etc and set the position of the body directly.

我不知道Andengine，所以这只是伪code：

I don't know Andengine, so this is just pseudocode:

public void updateGameLoop(float deltaTime) {
    Vector2 current = body.getPosition();
    Vector2 target = new Vector2(100, 100);

    if (!current.equals(target)) {
        float speed = 20f;
        Vector2 direction = target.sub(current);
        float distanceToTarget = direction.len();
        float travelDistance = speed * deltaTime;

        // the target is very close, so we set the position to the target directly
        if (distanceToTarget <= travelDistance) {
            body.setTransform(target, body.getAngle());
        } else {
            direction.nor();
            // move a bit in the target direction 
            body.setTransform(current.add(direction.mul(travelDistance)), body.getAngle());
        }
    }
}

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