I am trying to recreate a screensaver where a small object, such as a ball, travels around the screen and bounces of the edges.

The ball speeds up and slows down.
I also want the ball to stretch when it is going faster, but since the ball isn't travelling at a right angle, I figured I couldn't do it.

Then I found rotate, and I can't get it to work right. Can someone show me how to properly use rotate without any other kind of translation and without matrices?

Sort of. I can get the rest of my program to work fine, but I can't get it to work when rotate is part of the program. I'm trying to rotate the ball 45 degrees, so that when it is moving quickly (up-left, down-right, etc.), it will stretch in that direction. I want to rotate my ellipse so that it stretches in the direction it is actually travelling, instead of on the x or y axis.

Thankyou!Thankyou!Thankyou!Thankyou!Thankyou!Thankyou!Thankyou!Thankyou!Thankyou
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I have no idea what pushMatrix and popMatrix are actually doing (never got into matrices in precalc), but all the examples of translations use them, so I added them, and I tried your idea for drawing at (0,0) and then translating the objects to the desired position, and IT WORKS! YAY!

So far, it will only stretch in one direction, but I just need to adjust the code that determines my rotation angle variable. I'll post the actual code so you can see how I was doing everything once that's working.

EDIT: I guess my original request (no matrices) doesn't work if you want translations, huh?

Okay, here's my code. I would've posted it earlier, and I probably would've gotten some better help from you guys, but this is for school homework, and I doubt my instructor would like seeing my project here before it's done and turned in.


//Bouncy Ball by compsciguy

//Initializing variables
int x;
int y;
int speedX;
int speedY;
int speed;
int speedCounter = 0;
int speedDirection = 1; //For speedDirection, 1=Up and 0=Down
float circleWidth = 70.0;
float circleHeight = 70.0;
boolean stretched = false;
float rotation;
int Rbg;
int Gbg;
int Bbg;
int Rball;
int Gball;
int Bball;
int colorChanger = 0;

//Setting up
void setup() {
 size(768,512);
 frameRate(30);
 x = (width/2);
 y = (height/2);
 //Randomly choose colors for background and ball
 Rbg = int(random(0,255));
 Gbg = int(random(0,255));
 Bbg = int(random(0,255));
 if(Rbg > 127) {
   Rball = Rbg - 128;
 } else {
   Rball = Rbg + 128;
 }
 if(Gbg > 127) {
   Gball = Gbg - 128;
 } else {
   Gball = Gbg + 128;
 }
 if(Bbg > 127) {
   Bball = Bbg - 128;
 } else {
   Bball = Bbg + 128;
 }
 smooth();//Apparently this enables anti-aliasing (avoids pixelized curves)
}

void draw() {
 //These lines randomly choose a starting direction for the ball; BETWEEN -2 and 2 because random does not include
 while(speedX == 0) {
 speedX = int(random(-2,2));
 speedX *= 5;
 println(abs(speedX));
 }
 while(speedY == 0) {
 speedY = int(random(-2,2));
 speedY *= 5;
 }
 background(Rbg,Gbg,Bbg);
 //Makes the ball move across the screen
 x = x + speedX;
 y = y + speedY;
   
 //This will make the ball speed up or slow down after it has traveled 30 increments of its speed
 //speedCounter increments by 1 at the end of the draw function
 if(speedCounter == 30) {
   if(speedDirection == 1) {
     if(speedX > 0) {
       speedX++;//Travelling right, speeding up
     } else {
       speedX--;//Travelling left, speeding up
     }
     if(speedY > 0) {
       speedY++;//Travelling down, speeding up
     } else {
       speedY--;//Travelling up, speeding up
     }
   }
   if(speedDirection == 0) {
     if(speedX > 0) {
       speedX--;//Travelling right, slowing down
     } else {
       speedX++;//Travelling left, slowing down
     }
     if(speedY > 0) {
       speedY--;//Travelling down, slowing down
     } else {
       speedY++;//Travelling up, slowing down
     }
   }
   speedCounter = 0;
   println(abs(speedX));
 }
 
 //Make the ball slow down if it is speeding up and the speed reaches 30
 if(abs(speedX) == 30) {
   if(speedDirection == 1) {
     speedDirection = 0;
   }
 }

 //Make the ball speed up if it is slowing down and the speed reaches 1
 if(abs(speedX) == 5) {
   if(speedDirection == 0) {
     speedDirection = 1;
   }
 }

 //When the ball's edge reaches a wall, it will change direction
 //I added some code here so that it would change direction when the EDGE of the
 //ball touched the side, instead of the middle of the ball
 //UPDATE: When I rotate the ball, it bounces when the edge is just past the wall;
 //This creates an effect like the ball is invisibly squishing into the wall before bouncing off
 if ((x > width - (circleHeight*(sqrt(2)/4))) || (x < 0 + (circleHeight*(sqrt(2)/4)))) {
   speedX = speedX * -1;
   colorChanger++;
 }
 if ((y > height - (circleHeight*(sqrt(2)/4))) || (y < 0 + (circleHeight*(sqrt(2)/4)))) {
   speedY = speedY * -1;
   colorChanger++;
 }