Bouncing Ball Program

Programming Questions

wyrzski

in Programming Questions • 11 months ago

I'm trying to write a program where a ball accelerates towards the ground and bounces until it reaches rest position at the bottom of the screen, unfortunately i can't get the ball to bounce. Can anyone see any reason the ball won't bounce? Any help is appreciated.

//Creates a bouncing ball that accelerates towards the ground

class Ball{

float x;

float y;

float vy;

float ay;

int radius;

int redness;

int greenness;

int blueness;

float time;

int bounces;

//defines a constructor

Ball(float p1,float p2, float p3, float p4, int p5, int p6, int p7, int p8, float p9, int p10){

x=p1;

y=p2;

vy=p3;

ay=p4;

radius=p5;

redness=p6;

greenness=p7;

blueness=p8;

time=p9;

bounces=p10;

}

Ball myball;

float timepassed=0;

void setup(){

size(500,500);

frameRate(60);

myball=new Ball(0,-25,0,0,25,int(random(255)),int(random(255)),int(random(255)),0,0);

}

void draw(){

background(255);

if(mousePressed==true)

{myball=new Ball(mouseX,-25,0,98,25,int(random(255)),int(random(255)),int(random(255)),0,0);

mousePressed=false;

}

drawball(myball);

}

void drawball(Ball aball){

fill(aball.redness,aball.greenness,aball.blueness);

ellipse(int(aball.x),int(aball.y),aball.radius,aball.radius);

aball.y=aball.y+(aball.vy*timepassed)+(0.5*aball.ay*aball.time*aball.time);

aball.vy=aball.vy+(aball.ay*aball.time);

aball.time=aball.time+0.01667;

if(aball.y>=height)

{aball.vy=(-0.9)*aball.vy;

aball.bounces=aball.bounces+1;

aball.time=0;

}

Replies(2)

Doctor Ba..

Re: Bouncing Ball Program

11 months ago

Firstly, when posting code in the forum, on the right of the little smiley icon there is an option to put your code in a proper code format. That's no big deal though, just a heads up for easier reading.

I honestly found your code a bit confusing with all of the different values that the ball class constructed with, but who am I to tell you how to write your code. All that I can offer is a simple piece of code to do this exact thing copied from the book, Learning Processing by Daniel Shiffman:

float x = 100; // x location of square
float y = 0; // y location of square
float speed = 0; // speed of square
float gravity = 0.1;
void setup() {
size(200, 200);
}
void draw() {
background(255);
// Display the square
fill(0);
noStroke();
rectMode(CENTER);
rect(x, y, 10, 10);
y = y + speed;
speed = speed + gravity;
// If square reaches the bottom
// Reverse speed
if (y > height) {
speed = speed * -0.95;
}
}

This code example is what I think you are trying to do, and maybe by comparing it with your code you can discern the problem.

PhiLho

Re: Bouncing Ball Program

11 months ago

Simple change:

if(aball.y>=height)
{
println(aball.y + " " + height);
aball.vy=(-0.9)*aball.vy;
aball.bounces=aball.bounces+1;
aball.time=0;
}

As you can see, aball.y is a lot greater than height, so after inverting the speed, it doesn't go higher enough to rebound and remains stuck below the bottom.

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