大家怎么了
谢谢你的时间。
我正在制作 Pong 克隆，并且我想将 Box2D 限制为最多两个 MouseJoint；每个桨最多一个 MouseJoint。只有当用户的两次触摸之一落在两个桨的边界内时，才应创建 MouseJoint。
我的代码得到了一个奇怪的结果。如果我的第一次触摸落在左侧拨片内，而我的第二次触摸落在任一拨片之外，则在左侧拨片上创建第二个 MouseJoint（见附图）。
注意：图中除了左边的两个MouseJoints外，还有两个PrismaticJoints；一个附在每个桨上。
无济于事，我尝试了所有我能想到或从其他人的代码中改编的算法。
如果可以发布代码解决方案示例或链接，我将不胜感激。
这是我的代码：
public class MyScreen implements Screen, InputProcessor{
/*========some variables and methods omitted for clarity========*/
/*multiple mouse joint experiment*/
public MouseJoint mouseJoint[] = new MouseJoint[2];
Body hitBody[] = new Body[2];
Body tempBody;
public MyScreen(Pong game) {
this.game = game;
}
/*---------------------Screen interface methods--------------------------*/
//methods omitted for clarity
/*---------------------end Screen interface methods----------------------*/
/*---------------------InputProcessor interface methods------------------*/
@Override
public boolean keyDown(int keycode) {
return false;
}
@Override
public boolean keyUp(int keycode) {
return false;
}
@Override
public boolean keyTyped(char character) {
return false;
}
@Override
public boolean touchDown(int screenX, int screenY, int pointer, int button) {
testPoint.set(screenX, screenY, 0);
camera.unproject(testPoint);
// ask the world which bodies are within the given
// bounding box around the mouse pointer
hitBody[pointer] = null;
world.QueryAABB(callback, testPoint.x - 1.0f, testPoint.y - 1.0f, testPoint.x + 1.0f, testPoint.y + 1.0f);
hitBody[pointer] = tempBody;
// if we hit something we create a new mouse joint
// and attach it to the hit body.
if (hitBody[pointer] != null) {
MouseJointDef def = new MouseJointDef();
def.bodyA = groundBody;
def.bodyB = hitBody[pointer];
def.collideConnected = true;
def.target.set(hitBody[pointer].getPosition().x, hitBody[pointer].getPosition().y);
def.maxForce = 3000.0f * hitBody[pointer].getMass();
mouseJoint[pointer] = (MouseJoint)world.createJoint(def);
hitBody[pointer].setAwake(true);
} else {
}
return false;
}
@Override
public boolean touchUp(int screenX, int screenY, int pointer, int button) {
if (mouseJoint[pointer] != null) {
world.destroyJoint(mouseJoint[pointer]);
mouseJoint[pointer] = null;
}
return false;
}
/**a temporary vector for delta target destination during touchDragged() method**/
Vector2 target = new Vector2();
@Override
public boolean touchDragged(int screenX, int screenY, int pointer) {
if (mouseJoint[pointer] != null) {
camera.unproject(testPoint.set(screenX, screenY, 0));
mouseJoint[pointer].setTarget(target.set(testPoint.x, testPoint.y));
}
return false;
}
@Override
public boolean mouseMoved(int screenX, int screenY) {
return false;
}
@Override
public boolean scrolled(int amount) {
return false;
}
/*----------------end InputProcessor interface methods------------------*/
/*------------------------helper methods------------------------------------*/
/*android screen touch vector for a mouse joint*/
Vector3 testPoint = new Vector3(); //we instantiate this vector and the callback here so we don't irritate the GC
QueryCallback callback = new QueryCallback() {
@Override public boolean reportFixture (Fixture fixture) {
// if the hit fixture's body is the ground body
// we ignore it
if (fixture.getBody() == groundBody) return true;
if (fixture.testPoint(testPoint.x, testPoint.y)) {
tempBody = fixture.getBody();
return false;
} else
return true;
}
};
/*------------------------end helper methods-------------------------------*/
}