Help with opposite way bouncing ball

Programming Questions

jts2315

Help with opposite way bouncing ball

in Programming Questions • 8 months ago

Hello I am completely new to processing.

Anyway I found this code for a ball which scrolls down the screen but I want to make it go the other way but cant get it to move the opposite way, also what does y-- mean ? Heres the code:

int x;

 int y;

void setup() {

size(500,500);

 x = width/2;

 y = height/2; }

void draw() {

background(200,100,100);

fill(100,200,100);

ellipse(x, y, 100, 100);

 y++;

if(y>height)

 y=0;

Thanks for any help you can give me.

Replies(2)

asimes

Re: Help with opposite way bouncing ball

8 months ago

y++ means add one to y and y-- means subtract one from y. It is the same as y = y-1. In Processing moving up means subtracting, so you want y--.

You might notice that the ellipse() jumps when it is halfway through the bottom of the screen in your code. That is because the ellipse() is drawn from the center. When the center passes the height, it jumps to the top. The way to fix this is to add the radius to the jump condition (the radius is 50).

int x, y;
void setup() {
size(500, 500);
x = width/2;
y = height/2;
}
void draw() {
background(200, 100, 100);
fill(100, 200, 100);
ellipse(x, y, 100, 100);
y--;
if (y < -50) y = height+50;
}

jts2315

Re: Re: Help with opposite way bouncing ball

8 months ago

Thanks very much for the great help

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