box2d

问题 I am trying to move a body with no gravity to the click or touch position and then stop it. However, depending where I click it moves really fast or really slow because of the coordinates of my Vector3. Also, it behaves like that game asteroids which I do not want. Basically, I just need myBody follows the click of the mouse our touch. Here where I have got so far: @Override public boolean touchDown(int screenX, int screenY, int pointer, int button) { camera.unproject(touchPosition.set

问题 I know this question has been asked before, but no one has given any helpful answers as to how to fix it. I have a cocos2d ios application that uses the box2d physics engine. I ran a performance test on it and the cpu spends 5.6% of its time on mach_msg_trap. From what I have gathered from other questions, it seems as if mach_msg_trap is just the main thread waisting time as a result of your application being idle. My application isn't idle though. It has shaky performance and hovers in the

问题 I have a Fast Moving Body(A) which is dynamic. It is supposed to collide with another Body(B). A collides with B, but sometimes it passes the Body B without collision. This is totally random behavior. I must have that collision. Kindly guide why it is acting like this, randomly. 回答1: The effect of one object passing through another due to large movement in a single timestep is called tunneling . Box2D uses Continuous Collision Detection between dynamic and static objects to solve this problem

问题 I'm using the UIPinchRecognizer and an open pinch to detect when someone 'pulls apart' a sprite in a Box2D world. The problem is that when you drag two items toward each other it detects this as a close pinch and breaks all my touchjoints and the movement of the box2d objects. I've tried to split my problem into two questions - the question you're reading now: is it is possible to suppress the close pinch, and if that's not possible: how to detect an open pinch myself. I need to either

问题 This question already has answers here : What does suffix 'f' mean in Java code? (5 answers) Closed 5 years ago . It seems to be used in value declarations in the engine but the documentation of JBox-2D does not explain what this 'unit' is. Example: float x = 20.0f //<-- this 'f' FixtureDef fixDef = new FixtureDef(); fixDef.shape = shape; fixDef.density = 0.0f; //<-- this 'f' fixDef.friction = 0.9f; //<-- this 'f' What is it? If it is indeed a unit, what is it relative to? What benefit does

问题 I have created a revoluteJoint with a motor and lower & upper limits. I would like to know how to make the revoluteJoint oscillate between the lower & upper limits. Currently the body swings from the lower to the upper limit and then stops. Any help will be appreciated. This is the code final RevoluteJointDef revoluteJointDef2 = new RevoluteJointDef(); revoluteJointDef2.initialize(legBody, circleBody1, circleBody1.getWorldCenter()); revoluteJointDef2.enableMotor = true; revoluteJointDef2

问题 Kindly suggest some explanation or code regarding how can i detect collision between a specific part of one body with another body in box2d with libgdx.I am able to detect simple collision between two bodies using Contact Listener as mentioned hereBut I also want to check which part of bodies are ovelapping . Thanks, 回答1: The ContactListener provides you with Contact as a callback parameter. Those contacts will tell you which Fixtures did collide via contact.getFixtureA() and contact

问题 I have the following shape: http://s16.postimg.org/sfhb5wgdx/slime.png and I want to draw it in LibGDx just like that because am using Box2d wand will be used in collisions. I have heard I can used a mesh to create this but there isn't much documentation about drawing anything from an image. Do I seriously have to define all the points myself? Is there a better way to extract a shape from in image? 回答1: Use Physics body editor https://code.google.com/p/box2d-editor/ this will solve your

问题 I'm using the UIPinchRecognizer and an open pinch to detect when someone 'pulls apart' a sprite in a Box2D world. If I use UIPinchGestureRecognizer to detect pull aparts, it breaks my mouse joints when two objects are dragged together - which is less than ideal. I've tried to split my problem into two questions - how to detect an open pinch without UIPinchGestureRecognizer and is it is possible to suppress the close pinch. How can I write my own class to detect an open pinch? That is, two

问题 I am developing a game in Libgdx and I am working on collision detection between two bodies in box 2D. I used "Contact Listener" to detect collision but nothing happens when the bodies collide. This is my code public Player(World world,float x,float y,float width) { this.width=width; //IMP height=width*2; BodyDef polygon=new BodyDef(); polygon.type=BodyType.DynamicBody; polygon.position.set(x,y); // polygon.fixedRotation=true; PolygonShape poly =new PolygonShape(); poly.setAsBox(width/2