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我目前正在使用 box2d 制作弹射器游戏，但我遇到了弹射器臂旋转的问题。

让我解释一下我的弹射器：

我有 2 个对象。* 弹射器臂 - 动态体 * 弹射器底座 - 静态体

我想让弹射臂在一定范围内来回旋转。这是我的弹射器的图像：http: //i.gyazo.com/7ce4dfa87b2083a0eb62df7c4acd3e47.png

现在，我尝试使用关节“链接它们”，但没有奏效。最初，我希望手臂向左弯曲一点。我有自己的游戏世界对象，其中包含 Box2d 世界对象和所有游戏对象。此外，我有一个名为 Game Renderer 的对象，它负责游戏中的渲染。到目前为止，这是我在 Game World 对象中尝试过的内容：

package com.david.gameworld;

import com.badlogic.gdx.math.Vector2;
import com.badlogic.gdx.physics.box2d.World;
import com.badlogic.gdx.physics.box2d.joints.RevoluteJointDef;
import com.david.objects.CatapultArm;
import com.david.objects.CatapultBase;

public class GameWorld{

    private World b2dWorld;
    private CatapultArm arm;
    private CatapultBase base;
    private RevoluteJointDef jointDef;
    public GameWorld() {
        // Initialize The Box2d World
        b2dWorld = new World(new Vector2(0,0),true);
        initializeObjects();
    }
    public CatapultArm getArm() {
        return arm;
    }
    public CatapultBase getBase() {
        return base;
    }
    public World getBox2DWorld() {
        return b2dWorld;
    }
    public void updateWorld(float delta) {
        b2dWorld.step(1/delta, 8, 5);
    }
    private void initializeObjects() {
        // Initialize The Objects(Catapult, Base)
        arm = new CatapultArm(b2dWorld);
        base = new CatapultBase(b2dWorld);
        jointDef = new RevoluteJointDef();
        jointDef.initialize(arm.getBody(), base.getBody(), new Vector2(120,62));
        jointDef.enableMotor = true;
        jointDef.enableLimit = true;
        jointDef.motorSpeed = -1260;
        jointDef.lowerAngle = (float) Math.toRadians(90);
        jointDef.upperAngle = (float) Math.toRadians(75);;
        jointDef.maxMotorTorque = 4800;
        b2dWorld.createJoint(jointDef);
    }
}

CatapultArm 和 CatapultBase 都是我游戏中的对象，其中包含身体的所有配置（位置、类型等）。

以下是代码：

CatapultBase.java

package com.david.objects;

import com.badlogic.gdx.physics.box2d.BodyDef;
import com.badlogic.gdx.physics.box2d.World;
import com.badlogic.gdx.physics.box2d.BodyDef.BodyType;

public class CatapultBase extends ObjectInWorld{

    public CatapultBase(World world) {
        super(world);
        initiate();
    }
    @Override
    protected void initiate() {
        //The Body
        bodyDef = new BodyDef();
        bodyDef.type = BodyType.StaticBody;
        bodyDef.position.set(140f, 62f);
        body = world.createBody(bodyDef);
    }
}

CatapultArm.java

package com.david.objects;

import com.badlogic.gdx.physics.box2d.BodyDef;
import com.badlogic.gdx.physics.box2d.BodyDef.BodyType;
import com.badlogic.gdx.physics.box2d.World;

public class CatapultArm extends ObjectInWorld{

    public CatapultArm(World world) {
        super(world);
        initiate();
    }

    @Override
    protected void initiate() {
        //The Body
        bodyDef = new BodyDef();
        bodyDef.type = BodyType.DynamicBody;
        bodyDef.position.set(154f, 62f);
        body = world.createBody(bodyDef);
    }
}

ObjectInWorld.java

package com.david.objects;

import com.badlogic.gdx.physics.box2d.Body;
import com.badlogic.gdx.physics.box2d.BodyDef;
import com.badlogic.gdx.physics.box2d.World;

public abstract class ObjectInWorld {

    protected BodyDef bodyDef;
    protected Body body;
    protected World world;
    protected ObjectInWorld(World world) {
        this.world = world;
    }

    protected void initiate() {

    }
    public float getX() {
        return body.getPosition().x;
    }
    public float getY() {
        return body.getPosition().y;
    }
    public Body getBody() {
        return body;
    }
}

我怎样才能将弹射器臂“固定”到底座上，以便它可以很好地旋转？

4

1 回答 1

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Your bodies don't have any fixtures on them. In the original C++ version at least, this would cause them to have no density, and therefore no mass, so they would be treated as fixed rotation.

于 2014-09-28T05:30:34.787 回答