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Java. Balls split after collision and move in different directions

I have a program where i create balls that bounce around. When two balls collide, both should split into two smaller balls, start moving in different directions.
This is how I handle collision
public boolean intersects (Ball b) {
double distance = Math.sqrt(Math.pow((this.x - b.x), 2) + Math.pow((this.y - b.y), 2));
if (this.size / 2 + b.size / 2 >= distance && !(this.equals(b))) {
return true;
} else return false;
I am looking for an idea, that will help to decide where to place smaller balls, so that they don't immediately collide again. I have tried different maneuvers but they all end up too close to each other so they all start splitting a bouncing and it become a chaos.
Here is the class Ball
public Ball(double x, double y, double size, double dx, double dy) {
this.x = x;
this.y = y;
this.size = size;
this.dx = dx;
this.dy = dy;
To move the balls I do the following
b.x = b.x + b.dx;
b.y = b.y + b.dy;
For the moment when the balls collide, i have two Ball Objects. I know the coordinates of their centers: x, y , speed dx with which they move along the x-axis and speed dy along the y-axis
I leave out the code that handles the view, cause I basically need a solution, how to change dx, dy, x and y for 4 balls, so that all of them move away from each other and do not immediately collide.
I don't really need code-solution , but rather a general idea.

I think you might have two problems. The first is that your four "new" balls are all starting at or near the point of collision, and your collision detector might immediately perceive them as colliding. To solve this, you could mark the "new" balls as unable to collide with each other for a pulse or two of your collision detector. I'd need to see the code to give a better solution.
Secondly, you'll probably want to randomize the result vector of the four "new" balls. Just set dx and dy randomly for each and that should be good enough.

FPS Mouse movement in OpenGL (even outside window)

I'm creating a simple FPS game where the camera movement is controlled with the mouse. It's fairly simple to move the camera with the mouse when it's inside the window. But how can I make this work even when I'm OUT of the window?
I've heard some thing about fixing the mouse in the center of the screen, but I'm not sure how to get this to work.
I currently have the following:
public void mouseMoved(MouseEvent event) {
x = X;
y = Y;
X = event.getX();
Y = event.getY();
}
public void update() {
dX = X - x;
dY = Y - y;
x = X;
y = Y;
}

I've heard some thing about fixing the mouse in the center of the screen, but I'm not sure how to get this to work.
That is a very common way to do it. After you have checked how much your mouse has moved and used that information for camera movement, just move the cursor back to screen center.
Consider something like this:
Vec2 mouseDelta = getMousePosition();
camera.CalculateMovement(mouseDelta);
setMousePosition(0, 0);

You need to "capture" the mouse in your window, typically on the mouse down ( don't forget to release it ).
onMouseDown()
{
BeginCapture();
}
...
ReleaseCapture();

Creating "stick controls" for android game?

I'm trying to create a simple Android game, a 2D action shooter which has 2 control sticks (circles) on the screen, the left one is movement control and the right one weapon control. Direction is being controlled by the position of your thumb relative to the circle’s center.
I've been following a tutorial on this site: http://www.kilobolt.com/day-7-creating-an-android-game-from-start-to-finish.html but it only gave me the base to work on. I have no programming experience so I'm quite lost now.
I got the movement working only on TOUCH_DOWN event, the hero moves to about where it should but to change direction I have to lift my thumb and touch the circle again. TOUCH_DRAGGED (or ACTION_MOVE) is broken because if I drag my finger across the circle the character moves really fast. I guess the problem is too many touch events are being handled, but I have no idea how to fix it.
How can I change this so that I can drag my thumb around the circle and the hero will change its direction instantly, and keep its speed constant all the time? Also the speed should be the same no matter how close or far from the center of the circle you touch.
private void updateRunning(List<TouchEvent> touchEvents, float deltaTime) {
int len = touchEvents.size();
for (int i = 0; i < len; i++) {
TouchEvent event = touchEvents.get(i);
if (event.type == TouchEvent.TOUCH_DOWN || event.type == TouchEvent.TOUCH_DRAGGED) {
if (inBounds(event, 50, 300, 150, 150, 'c')) {
ctrl.setX(event.x);
ctrl.setY(event.y);
ctrl.direction();
hero.move(ctrl.getDirX(), ctrl.getDirY());
}
}
if (event.type == TouchEvent.TOUCH_UP) {
if (inBounds(event, 0, 0, 35, 35,'r')) {
pause();
}
hero.stopMove();
}
}
hero.update();
The movement: hero's speedX and speedY are added to hero's centerX and centerY on every hero.update() call.
public void move(float x, float y) {
speedX += x * MOVESPEED;
speedY += y * MOVESPEED;
}
This method that handles the x & y speed. Found it here at stackoverflow, and because touch_down event is working ok, I guess it's doing it's job. Although I feel it's not exactly how it's supposed to be. L_STICK_C is a constant with values of 100 and 350 (center of the circle).
public void direction() {
dir.x = x - L_STICK_C.x;
dir.y = y - L_STICK_C.y;
double hyp = Math.sqrt(dir.x * dir.x + dir.y * dir.y);
dir.x = (float) (dir.x / hyp);
dir.y = (float) (dir.y / hyp);
}

I suggest you look into some game programming tutorials. You usually would not move the character directly from the touch input. You'd set a game state variable once a game loop which would correspond to the position of your thumb inputs. Then you'd only update the hero once per game loop based on those inputs. This lets allows you to keep the game input control code, and hero code separate, and makes it re-usable for other parts of your game.
EDIT:
Based on your code, every time you drag your finger, you generate a bunch of dragged events. So you are adding onto your characters speed for each event. You should probably just be looking at the distance to center and x / y of the input on the last touch event, not all of them.

Proper Collision

So basically im trying to figure out how to make a proper collision between two Rectangles.
Detecting isn't the problem, but the rectangles begin to clip. I wanted to reset the position, but how do I do that.
I'm trying to use dx and dy to reset, but it won't reset to the right coordinates.
http://i.stack.imgur.com/IU6sK.png (Sorry I can't use images yet)
System.out.println(this.y + this.h + " " + e.getY());
if(this.y + this.h >= e.getY())
{
if(this.dy > 0)
{
this.y -= delta * this.dy + 0.1;
this.dy = 0;
}
else
{
this.y += delta * this.dy;
this.dy = 0;
this.inAir = false;
}
}
This code is just an example to show how I am trying it for the top. (this = the white Rectangle and e = the orange one) I used my class Entity, which extends Rectangle.
I'm checking intersection before I call this. This is a function in the "white" Entity and the intersection is checked in the update function of the main loop.
If I use this, there is like 1px between the rectangles.
Any ideas?
Thanks for any help :)

http://docs.oracle.com/javase/6/docs/api/java/awt/Rectangle.html
Use the Rectangle class.
Here, some code
http://pastebin.com/raw.php?i=TzkST3Hm

The best way to do rectangular collision is to use the Rectangle class to detect collision using the .intersects(Rectangle) method, and then calculate a new variable called displacementX and displacementY.
displacementX = Math.abs(entitiy1.getX() - entity2.getX());
displacementY = Math.abs(entitiy1.getY() - entity2.getY());
So what we have currently is the amount of pixels entity1 is intruding on entity2 (or vice versa due to the absolute value). Then, run some comparisons and move entity1 (or entity2) by the value of the lesser displacement, which should yield perfect-looking collision.
This is at least how I do it. The correct method for rectangular collision is to:
1) Determine if they collide
2) Correct it
3) Render
Simply preventing movement after detecting collision will look horrible (especially on low frame rates).
Hope I helped!
~Izman

Android min3D using touch to rotate around an object

I'm trying to rotate the camera around an object by using the touchscreen. The rotation around Y axis works fine (The X axis is disabled). Rotation around the X axis is really weird. when the Object (its a rocket) gets higher rocket.position().y++ & scene.camera().position.y++, the rotation around the x axis gets bigger and weird. If the rockets stops rocket.position().y = 500; & scene.camera().position.y = 500;, I can't rotate around x axis, I zoom in or out the object instead. With both axis enabled its weird as hell.
In initScene I set the camera to look at the center of the rocket.
Here's my code:
initScene:
scene.camera().position.z = 90;
scene.camera().target = raketeOBJ.position();
onTouchEvent:
public boolean onTouchEvent(MotionEvent me) {
if (me.getAction() == MotionEvent.ACTION_DOWN) {
xpos = me.getX();
ypos = me.getY();
return true;
}
if (me.getAction() == MotionEvent.ACTION_UP) {
xpos = -1;
ypos = -1;
touchTurn = 0;
touchTurnUp = 0;
return true;
}
if (me.getAction() == MotionEvent.ACTION_MOVE) {
float xd = me.getX() - xpos;
float yd = me.getY() - ypos;
xpos = me.getX();
ypos = me.getY();
touchTurn = xd / -200f;
touchTurnUp = yd / -200f;
return true;
}
try {
Thread.sleep(15);
} catch (Exception e) {
}
return super.onTouchEvent(me);
}
UpdateScene:
if (touchTurn != 0) {
scene.camera().position.rotateY(touchTurn);
touchTurn = 0;
}
if (touchTurnUp != 0) {
scene.camera().position.rotateX(touchTurnUp);
touchTurnUp = 0;
}

I think it is a view-orientation-issue. try basic android opengl example "rotating cubes", i think it is a similar behaviour.
To avoid this you have to transform display-coordinates into min3D object rotation-coordinates.
Think about moving your finger 1cm on display to the left, with 3D-object following your finger. This means x_display = x_object.
If you rotate your object, there is still a fixed connection between display and object.
(x_display = - 1cm) equals (x_object = -1cm)
at 90° & 270° your object will move xy-inverted, at 180° your object will move x-inverted.
use some sin/cos to overcome this.
edit: also rotationangle (object) = - rotationangle (camera)

One option is to rotate the container itself instead of the camera. In min3d you often work with an Object3dContainer as a class variable in your activity that displays the model. When you get your MotionEvent you can use the method rotation() from your Object3dContainer class and set x or y properties as appropriate.

You keep saying wierd, but you know that it doesn't describe what you see. Rotate is actually method of Number3d. It doesn't know about the target, so I guess rotation is done according the center, not according the rocket (Didn't quite check that, just a guess). There might be 2 solutions:
The easiest thing is to set the rocket to (0,0,0) and instead moving the rocket, move evertything else. Well that would be a stupid suggestion. Forget it.
The other solution is to calculate camera rotation traectory using sin() and cos()
There might be a third solution, but I didn't think a a lot about it and it might be wrong. What you have to do is move the camera like target is at (0,0,0), rotate and then return the camera.
Would look like something like this:
Number3d target = scene.camera.target;
Number3d cp = scene.camera.position.clone();
// move position like target is (0,0,0)
cp.x -= target.x;
cp.y -= target.y;
cp.z -= target.z;
cp.roateX(angle);
// restore offset
cp.x += target.x;
cp.y += target.y;
cp.z += target.z;
scene.camera.position.setAllFrom(cp);
You can try 3 but don't rely it'll do the job.