AndEngine之PhysicsRevoluteJointExample

最新推荐文章于 2020-10-03 09:53:43 发布

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本文介绍了一个使用物理铰链关节的示例程序，通过创建静态盒子和动态圆形物体，并利用铰链关节让圆形物体围绕盒子旋转。示例中详细展示了如何设置物体属性、创建关节及连接线等。

public class PhysicsRevoluteJointExample extends BasePhysicsJointExample {
   // ===========================================================
   // Constants
   // ===========================================================

   // ===========================================================
   // Fields
   // ===========================================================

   // ===========================================================
   // Constructors
   // ===========================================================

   // ===========================================================
   // Getter & Setter
   // ===========================================================

   // ===========================================================
   // Methods for/from SuperClass/Interfaces
   // ===========================================================

   @Override
   public Scene onLoadScene() {
       final Scene scene = super.onLoadScene();
       this.initJoints(scene);
       Toast.makeText(this, "In this example, the revolute joints have their motor enabled.", Toast.LENGTH_LONG).show();
       return scene;
   }

   // ===========================================================
   // Methods
   // ===========================================================

   private void initJoints(final Scene pScene) {
       final int centerX = CAMERA_WIDTH / 2;
       final int centerY = CAMERA_HEIGHT / 2;

       final int spriteWidth = this.mBoxFaceTextureRegion.getTileWidth();
       final int spriteHeight = this.mBoxFaceTextureRegion.getTileHeight();

       final FixtureDef objectFixtureDef = PhysicsFactory.createFixtureDef(10, 0.2f, 0.5f);//密度，弹性，摩擦

       for(int i = 0; i < 3; i++) {
           //三个盒子位置
           final float anchorFaceX = centerX - spriteWidth * 0.5f + 220 * (i - 1);
           final float anchorFaceY = centerY - spriteHeight * 0.5f;
           //盒子固定
           final AnimatedSprite anchorFace = new AnimatedSprite(anchorFaceX, anchorFaceY, this.mBoxFaceTextureRegion);
           final Body anchorBody = PhysicsFactory.createBoxBody(this.mPhysicsWorld, anchorFace, BodyType.StaticBody, objectFixtureDef);
           //移动的圆
           final AnimatedSprite movingFace = new AnimatedSprite(anchorFaceX, anchorFaceY + 90, this.mCircleFaceTextureRegion);
           final Body movingBody = PhysicsFactory.createCircleBody(this.mPhysicsWorld, movingFace, BodyType.DynamicBody, objectFixtureDef);

           anchorFace.animate(200);
           anchorFace.animate(200);
           anchorFace.setUpdatePhysics(false);
           movingFace.setUpdatePhysics(false);

           pScene.getTopLayer().addEntity(anchorFace);
           pScene.getTopLayer().addEntity(movingFace);
           //三条线
           final Line connectionLine = new Line(anchorFaceX + spriteWidth / 2, anchorFaceY + spriteHeight / 2, anchorFaceX + spriteWidth / 2, anchorFaceY + spriteHeight / 2);
           pScene.getBottomLayer().addEntity(connectionLine);
           this.mPhysicsWorld.registerPhysicsConnector(new PhysicsConnector(anchorFace, anchorBody, true, true, false, false){
               @Override
               public void onUpdate(final float pSecondsElapsed) {
                   super.onUpdate(pSecondsElapsed);
                   final Vector2 movingBodyWorldCenter = movingBody.getWorldCenter();
                   connectionLine.setPosition(connectionLine.getX1(), connectionLine.getY1(), movingBodyWorldCenter.x * PhysicsConstants.PIXEL_TO_METER_RATIO_DEFAULT, movingBodyWorldCenter.y * PhysicsConstants.PIXEL_TO_METER_RATIO_DEFAULT);
               }
           });
           this.mPhysicsWorld.registerPhysicsConnector(new PhysicsConnector(movingFace, movingBody, true, true, false, false));

           final RevoluteJointDef revoluteJointDef = new RevoluteJointDef();
           revoluteJointDef.initialize(anchorBody, movingBody, anchorBody.getWorldCenter());//绕中心转
           revoluteJointDef.enableMotor = true;//马达
           revoluteJointDef.motorSpeed = 10;
           revoluteJointDef.maxMotorTorque = 200;//扭矩

           this.mPhysicsWorld.createJoint(revoluteJointDef);
       }
   }

   // ===========================================================
   // Inner and Anonymous Classes
   // ===========================================================
}