在libgdx中，如何在矩形顶部附加圆形？

Question

我创建了一个体，我创建了两个独立的固定装置，一个固定装置创建一个矩形形状，另一个固定装置创建一个圆形。但是当我使用.createfixture时，它将圆圈放在矩形的中心，我希望圆形在矩形的顶部，就像火柴一样。

这是我的代码不知道该做什么......

rectangleBodyDef = new BodyDef();
rectangleBodyDef.type = BodyType.DynamicBody;
rectangleBodyDef.position.set(10,20);
rectangleBody = world.createBody(rectangleBodyDef);
rectangleBodyShape = new PolygonShape();
rectangleBodyShape.setAsBox(2f, 0.75f);
rectangleBodyFixtureDef = new FixtureDef();
rectangleBodyFixtureDef.shape = rectangleBodyShape;
rectangleBodyFixtureDef.restitution = 0.8f;
rectangleBody.createFixture(rectangleBodyFixtureDef);


/**********************CREATING THE SECOND BODY (CIRCLE BODY) ************/


circleShape = new CircleShape();
circleShape.setRadius(0.75f);
circleFixtureDef = new FixtureDef();
circleFixtureDef.shape = circleShape;
circleFixtureDef.restitution = 0.8f;
rectangleBody.createFixture(circleFixtureDef);

Answer 1

Fixture Definitions相对于身体位置，将CircleShape位置设置为略高于矩形的位置：

CircleShape circleShape = new CircleShape();
circleShape.setRadius(0.75f);

circleShape.setPosition(new Vector2(0,2));   //<------Add this

FixtureDef circleFixtureDef = new FixtureDef();
circleFixtureDef.shape = circleShape;
circleFixtureDef.restitution = 0.8f;
rectangleBody.createFixture(circleFixtureDef);

Answer 2

circleFixtureDef的位置相对于rectangleBody的位置。将circleFixtureDef的位置设置为0,0以外的其他值。