Box2D LibGDX绳索问题

Question

I am creating a rope with a series of Box2D bodies with the following code: 我正在使用以下代码创建带有一系列Box2D实体的绳索：

public void create(float length, float ropeLength){
    Array<Body> bodies = new Array<Body>();
    bodies.add(BodyFactory.createBox(world, position.x, position.y, length, length, BodyType.StaticBody, 0, 0, 0, "RopeMain"));

    for(int i = 1; i < ropeLength; i++){
        bodies.add(BodyFactory.createBox(world, position.x, position.y - (((length/2) / Core.PPM) * i),
                length, length, BodyType.DynamicBody, 0, 0, 0, "RopeBody" + i));

        RopeJointDef rDef = new RopeJointDef();
        rDef.bodyA = bodies.get(i - 1);
        rDef.bodyB = bodies.get(i);
        rDef.collideConnected = true;
        rDef.maxLength = (length/2)/Core.PPM;
        rDef.localAnchorA.set(position.x, -((length / 2) / Core.PPM));
        rDef.localAnchorB.set(position.x, ((length / 2) / Core.PPM));
        world.createJoint(rDef);
    }
}

Allow me to share some parameters... 请允许我分享一些参数...

For BodyFactory.createBox it requires the following: 对于BodyFactory.createBox它需要满足以下条件：

world, xPos, yPos, width, height BodyType, density, friction, restitution, fixture user data.(length is same because it uses boxes) 世界，xPos，yPos，宽度，高度BodyType，密度，摩擦力，恢复，夹具用户数据。（长度相同，因为它使用方框）

Core.PPM is the pixels per meter. Core.PPM是每米的像素。 Also note that the position is being divided by PPM in the constructor. 另请注意，该位置在构造函数中被PPM划分。

Question: why do the following lines shoot to the right? 问题：以下几行为何向右射击？

Any info is very helpful, also how will density, friction, and restitution affect the rope? 任何信息都非常有帮助，密度，摩擦力和恢复力将如何影响绳索？ Thanks! 谢谢！

Answer 1

The joint's localAnchor is relative to the center of the body and isn't an absolute value. 关节的localAnchor相对于身体的中心，不是绝对值。 That means that if you want to set the joint to the center-bottom of bodyA and center-top of bodyB you need to use 这意味着，如果要将关节设置为bodyA的中心底部和bodyA 中心顶部 ， bodyB需要使用

    rDef.localAnchorA.set(0, -((length / 2) / Core.PPM));
    rDef.localAnchorB.set(0, ((length / 2) / Core.PPM));

Box2D LibGDX绳索问题

问题描述

1 个解决方案

解决方案1
2 已采纳 2016-07-05 07:25:00

Box2D LibGDX绳索问题

问题描述

1 个解决方案

解决方案1 2 已采纳 2016-07-05 07:25:00

解决方案1
2 已采纳 2016-07-05 07:25:00