创建尺寸后如何更改尺寸 [英] How to change size after it has been created

问题描述

我正在使用java，libgdx和box2d

I am using java, libgdx, and box2d

在主班我创建了一个球员.我想将player.class中的shape.setAsBox更改为100.所以换句话说，我想在创建shape.setAsBox之后对其进行更改.我相信唯一的方法就是删除固定装置，然后重新创建一个尺寸为100的新装置.我怎样才能做到这一点.

In main class I have created a player. I want to change shape.setAsBox to 100 in player class. So in other words I want to change shape.setAsBox after it has been created. I believe only way to do this is to delete fixture and recreate a new one with 100 size. How can I do this.

public class main{
  ...
  public main(){
    //create player
    BodyDef bdef = new BodyDef();
    Body body;
    FixtureDef fdef = new FixtureDef();
    PolygonShape shape = new PolygonShape();

    /***Body - Player ***/
    bdef.type = BodyType.DynamicBody;
    bdef.position.set(50 / PPM, 50 / PPM);
    bdef.linearVelocity.set(1.5f, 0);
    body = world.createBody(bdef);

    /*** 1st fixture ***/
    shape.setAsBox(50/ PPM, 50 / PPM);
    fdef.shape = shape;
    fdef.filter.categoryBits = Constants.BIT_PLAYER;
    fdef.filter.maskBits = Constants.BIT_GROUND;
    body.createFixture(fdef).setUserData("player");

    player = new Player(body);
  }

  ....

  public void update(float dt) {
      playerObj.update(dt);
      ...
  }
}

//玩家班级

 public class player{
       public player(Body body){
             super(body);
       }

       ....
       public void update(){
             //get player x position
             currentX = this.getBody().getPosition().x;

             // how can I delete old fixture and recreate a new one? 
             // which will has shape.setAsBox = 100.
       }
}

推荐答案

销毁Fixture并重新定义它.由于您的播放器有一个Fixture，请跟踪它以将其删除或致电:

Destroy the Fixture and redefine it. Since your player has one Fixture, either keep track of it to remove it or call:

this.getBody().destroyFixture(this.getBody().getFixtureList().first());

然后在已经存在的Body中重新创建一个简单的形状:

Then recreate a simple shape in the already existing Body:

PolygonShape shape;
FixtureDef fdef;

// Create box shape
shape = new PolygonShape();
shape.setAsBox(100 / PPM, 100 / PPM);

// Create FixtureDef for player collision box
fdef = new FixtureDef();
fdef.shape = shape;
fdef.filter.categoryBits = Constants.BIT_PLAYER;
fdef.filter.maskBits = Constants.BIT_GROUND;

// Create player collision box fixture
this.getBody().createFixture(fdef).setUserData("player");
shape.dispose();

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