# LibGDX: How to make an object falls with random speed

I'm trying to make an object (ball) fall into position Y and when the ball collides with the base. The sprite changes and along with the change I want the speed of the fall to change according to the sprite

public void create () {
circleBall = new Circle();
rectangleBase = new Rectangle();
ball = new Texture("ball.png");
}

public void render () {
spriteBatch.begin();
fallBall();
rand();
spriteBatch.end();
}

void fallBall(){
fallSpeed++;
if(posYBall > 0){
posYBall -= fallSpeed * 2 / 2;
}
}

void rand(){
int rand1 = random.nextInt(15 - 1) + 1;
int rand2 = random.nextInt(10 - 1) + 1;
int rand3 = random.nextInt((55 - 35) + 1) + 35;
collisionBallBase(rand1, rand2, rand3);
}

void collisionBallBase(int rand1, int rand2, int rand3){
if(Intersector.overlaps(circleBall, rectangleBase)){
if(rand1 <= 5){
ball = new Texture("ball.png");
}else if(rand1 <= 10){
ball = new Texture("ballb.png");
}else{
ball = new Texture("ballc.png");
}

if(rand2 >= 5){
ballDirection = 4;
}else{
ballDirection = -4;
}
fallSpeed = -rand3;
}
}

• Just multiply fallSpeed with a variable that get's changed to some other random value every time your condition is met. You need to generate a random float that varies between, for example, 0.5 and 1.5. – VaTTeRGeR Feb 20 '19 at 10:30

Instead of calling the rand function in a render, you can call the function when your action happened.

If you want to have a ball with a random speed on creation time do it on the constructor.

If you want the ball to have a random speeds every time for each activity such a collision, set it in the 'on event' function.

If you really want to call a function in a render function then try something like this

boolean collided = false

somefunctionto
if(collided){
set_random_speed_to_a_ball(..);
collided = false;
}

render(){
if(collisionhappend){
collided = true;
}