How to make repeating 3D ball on Y-coordinate?

[processingart]

Hello, I was making an animation on processing. Then, I confused about on a problem. I prepare a simple code for you. Also, I think the question can helpfull for beginners.

PShape ball;
float ballSpeed = random(0.5,1);
float ballSize = random(5,10);
float x = 200, y = 300, z = 0;

void setup(){
size(400,400,P3D);
noStroke();            // That's for "not see details on sphere
ball = createShape(SPHERE, ballSize);
}

void draw(){
  background(0);
  translate(x, y, z);  // rotate the ball
  println(y);          // checking the y coordinates
  fill(255);
  shape(ball);
  y -= ballSpeed;      // the ball can go to top
}

So, I want to make a condition for if the ball reach the 100, the ball should start from the first position and then again it should go to 100 again. I tried many if contions but couldn’t figure out it.
If you help me I will be happy.
Thanks.

[slow_izzm]

Have you tried storing the value of ball y starting position in its own variable?

• if ball y current position is less than or equal to 100
• then set ball y current position equal to ball y starting position

[processingart]

Thank you @slow_izzm I found the solution. Your idea is true.
Let me write down the code. It can helpfull for beginners.

y -= ballSpeed;
if (y <= 100) {
   y = 300;
} 

[Chrisir]

Hello

and welcome to the forum!

Great to have you here!

note that a sphere looks better with lights()

here is a red one going back and forth (into the screen) - Z-axis

Warmest regards,

Chrisir

PShape ball;
float ballSpeed = -random(2.5, 3);
float ballSize = random(25, 35);
float x, y, z; 

void setup() {
  size(1400, 900, P3D);

  x = width/2-150; 
  y = 860-ballSize;
  z = 150;

  noStroke();            // That's for "not see details / lines on sphere"
  ball = createShape(SPHERE, ballSize);
  ball.setFill(color(0, 255, 0));
}

void draw() {
  background(0);
  lights(); 
  floor();

  translate(x, y, z);  // rotate the ball
  println(z);          // checking the y coordinates
  shape(ball);
  z += ballSpeed;      // the ball can go to top

  if (z <= -440) {
    ballSpeed =  abs(ballSpeed) ; // always pos
  }

  if (z > 0) {
    ballSpeed =  - abs(ballSpeed);  // always neg
  }
}//draw()

// ------------------------------------------------------------------------------------


// tab Floor 
// Floor: CheckeredFloor 

void floor () {
  noStroke();

  for (int i = 0; i < 30; i = i+1) {
    for (int j = 0; j < 30; j = j+1) {

      // % is modulo, meaning rest of division 
      if (i%2 == 0) { 
        if (j%2 == 0) { 
          fill (255, 0, 0);
        } else 
        {
          fill ( 103 );
        }
      } else {
        if (j%2 == 0) { 
          fill ( 103 );
        } else 
        {
          fill (255, 0, 0);
        }
      } // if

      pushMatrix();
      translate ( 80*i-610, 860, 80*j-940 );
      box ( 80, 7, 80);  // one cell / tile 
      popMatrix();
    } // for
  } // for
}//floor
// ---------------------------------------------------------------------------------

[processingart]

Thank you @Chrisir