如何在没有重力的情况下保持所有碰撞和加速效果。我想添加一个不会掉落到地面但如果没有碰撞附加保持其位置的主体。
public class PhysicsMouseJointExample extends SimpleBaseGameActivity implements IAccelerationListener, IOnSceneTouchListener, IOnAreaTouchListener {
// ===========================================================
// Constants
// ===========================================================
private static final int CAMERA_WIDTH = 720;
private static final int CAMERA_HEIGHT = 480;
private static final FixtureDef FIXTURE_DEF = PhysicsFactory.createFixtureDef(1, 0.5f, 0.5f);
// ===========================================================
// Fields
// ===========================================================
private BitmapTextureAtlas mBitmapTextureAtlas;
private TiledTextureRegion mBoxFaceTextureRegion;
private TiledTextureRegion mCircleFaceTextureRegion;
private Scene mScene;
private PhysicsWorld mPhysicsWorld;
private int mFaceCount = 0;
private MouseJoint mMouseJointActive;
private Body mGroundBody;
// ===========================================================
// Constructors
// ===========================================================
// ===========================================================
// Getter & Setter
// ===========================================================
// ===========================================================
// Methods for/from SuperClass/Interfaces
// ===========================================================
@Override
public EngineOptions onCreateEngineOptions() {
Toast.makeText(this, "Touch the screen to add objects.", Toast.LENGTH_LONG).show();
final Camera camera = new Camera(0, 0, CAMERA_WIDTH, CAMERA_HEIGHT);
return new EngineOptions(true, ScreenOrientation.LANDSCAPE_FIXED, new RatioResolutionPolicy(CAMERA_WIDTH, CAMERA_HEIGHT), camera);
}
@Override
public void onCreateResources() {
BitmapTextureAtlasTextureRegionFactory.setAssetBasePath("gfx/");
this.mBitmapTextureAtlas = new BitmapTextureAtlas(this.getTextureManager(), 64, 64, TextureOptions.BILINEAR);
this.mBoxFaceTextureRegion = BitmapTextureAtlasTextureRegionFactory.createTiledFromAsset(this.mBitmapTextureAtlas, this, "face_box_tiled.png", 0, 0, 2, 1); // 64x32
this.mCircleFaceTextureRegion = BitmapTextureAtlasTextureRegionFactory.createTiledFromAsset(this.mBitmapTextureAtlas, this, "face_circle_tiled.png", 0, 32, 2, 1); // 64x32
this.mBitmapTextureAtlas.load();
}
@Override
public Scene onCreateScene() {
this.mEngine.registerUpdateHandler(new FPSLogger());
this.mScene = new Scene();
this.mScene.setBackground(new Background(0, 0, 0));
this.mScene.setOnSceneTouchListener(this);
this.mScene.setOnAreaTouchListener(this);
this.mPhysicsWorld = new PhysicsWorld(new Vector2(0, SensorManager.GRAVITY_EARTH), false);
this.mGroundBody = this.mPhysicsWorld.createBody(new BodyDef());
final VertexBufferObjectManager vertexBufferObjectManager = this.getVertexBufferObjectManager();
final Rectangle ground = new Rectangle(0, CAMERA_HEIGHT - 2, CAMERA_WIDTH, 2, vertexBufferObjectManager);
final Rectangle roof = new Rectangle(0, 0, CAMERA_WIDTH, 2, vertexBufferObjectManager);
final Rectangle left = new Rectangle(0, 0, 2, CAMERA_HEIGHT, vertexBufferObjectManager);
final Rectangle right = new Rectangle(CAMERA_WIDTH - 2, 0, 2, CAMERA_HEIGHT, vertexBufferObjectManager);
final FixtureDef wallFixtureDef = PhysicsFactory.createFixtureDef(0, 0.5f, 0.5f);
PhysicsFactory.createBoxBody(this.mPhysicsWorld, ground, BodyType.StaticBody, wallFixtureDef);
PhysicsFactory.createBoxBody(this.mPhysicsWorld, roof, BodyType.StaticBody, wallFixtureDef);
PhysicsFactory.createBoxBody(this.mPhysicsWorld, left, BodyType.StaticBody, wallFixtureDef);
PhysicsFactory.createBoxBody(this.mPhysicsWorld, right, BodyType.StaticBody, wallFixtureDef);
this.mScene.attachChild(ground);
this.mScene.attachChild(roof);
this.mScene.attachChild(left);
this.mScene.attachChild(right);
this.mScene.registerUpdateHandler(this.mPhysicsWorld);
return this.mScene;
}
@Override
public void onGameCreated() {
this.mEngine.enableVibrator(this);
}
@Override
public boolean onSceneTouchEvent(final Scene pScene, final TouchEvent pSceneTouchEvent) {
if(this.mPhysicsWorld != null) {
switch(pSceneTouchEvent.getAction()) {
case TouchEvent.ACTION_DOWN:
this.addFace(pSceneTouchEvent.getX(), pSceneTouchEvent.getY());
return true;
case TouchEvent.ACTION_MOVE:
if(this.mMouseJointActive != null) {
final Vector2 vec = Vector2Pool.obtain(pSceneTouchEvent.getX() / PhysicsConstants.PIXEL_TO_METER_RATIO_DEFAULT, pSceneTouchEvent.getY() / PhysicsConstants.PIXEL_TO_METER_RATIO_DEFAULT);
this.mMouseJointActive.setTarget(vec);
Vector2Pool.recycle(vec);
}
return true;
case TouchEvent.ACTION_UP:
if(this.mMouseJointActive != null) {
this.mPhysicsWorld.destroyJoint(this.mMouseJointActive);
this.mMouseJointActive = null;
}
return true;
}
return false;
}
return false;
}
@Override
public boolean onAreaTouched(final TouchEvent pSceneTouchEvent, final ITouchArea pTouchArea, final float pTouchAreaLocalX, final float pTouchAreaLocalY) {
if(pSceneTouchEvent.isActionDown()) {
final IAreaShape face = (IAreaShape) pTouchArea;
/*
* If we have a active MouseJoint, we are just moving it around
* instead of creating a second one.
*/
if(this.mMouseJointActive == null) {
this.mEngine.vibrate(100);
this.mMouseJointActive = this.createMouseJoint(face, pTouchAreaLocalX, pTouchAreaLocalY);
}
return true;
}
return false;
}
@Override
public void onAccelerationAccuracyChanged(final AccelerationData pAccelerationData) {
}
@Override
public void onAccelerationChanged(final AccelerationData pAccelerationData) {
final Vector2 gravity = Vector2Pool.obtain(pAccelerationData.getX(), pAccelerationData.getY());
this.mPhysicsWorld.setGravity(gravity);
Vector2Pool.recycle(gravity);
}
@Override
public void onResumeGame() {
super.onResumeGame();
this.enableAccelerationSensor(this);
}
@Override
public void onPauseGame() {
super.onPauseGame();
this.disableAccelerationSensor();
}
// ===========================================================
// Methods
// ===========================================================
public MouseJoint createMouseJoint(final IAreaShape pFace, final float pTouchAreaLocalX, final float pTouchAreaLocalY) {
final Body body = (Body) pFace.getUserData();
final MouseJointDef mouseJointDef = new MouseJointDef();
final Vector2 localPoint = Vector2Pool.obtain((pTouchAreaLocalX - pFace.getWidth() * 0.5f) / PhysicsConstants.PIXEL_TO_METER_RATIO_DEFAULT, (pTouchAreaLocalY - pFace.getHeight() * 0.5f) / PhysicsConstants.PIXEL_TO_METER_RATIO_DEFAULT);
this.mGroundBody.setTransform(localPoint, 0);
mouseJointDef.bodyA = this.mGroundBody;
mouseJointDef.bodyB = body;
mouseJointDef.dampingRatio = 0.95f;
mouseJointDef.frequencyHz = 30;
mouseJointDef.maxForce = (200.0f * body.getMass());
mouseJointDef.collideConnected = true;
mouseJointDef.target.set(body.getWorldPoint(localPoint));
Vector2Pool.recycle(localPoint);
return (MouseJoint) this.mPhysicsWorld.createJoint(mouseJointDef);
}
private void addFace(final float pX, final float pY) {
this.mFaceCount++;
Debug.d("Faces: " + this.mFaceCount);
final AnimatedSprite face;
final Body body;
if(this.mFaceCount % 2 == 0) {
face = new AnimatedSprite(pX, pY, this.mBoxFaceTextureRegion, this.getVertexBufferObjectManager());
body = PhysicsFactory.createBoxBody(this.mPhysicsWorld, face, BodyType.DynamicBody, FIXTURE_DEF);
} else {
face = new AnimatedSprite(pX, pY, this.mCircleFaceTextureRegion, this.getVertexBufferObjectManager());
body = PhysicsFactory.createCircleBody(this.mPhysicsWorld, face, BodyType.DynamicBody, FIXTURE_DEF);
}
face.setUserData(body);
face.animate(200);
this.mScene.registerTouchArea(face);
this.mScene.attachChild(face);
this.mPhysicsWorld.registerPhysicsConnector(new PhysicsConnector(face, body, true, true));
}
// ===========================================================
// Inner and Anonymous Classes
// ===========================================================
}
我试图改变重力，但似乎什么都没有。
this.mPhysicsWorld = new PhysicsWorld(new Vector2(0, -10), false);