how to change balls that are falling from big to a smaller size gradually ?

michyg

help

(from here: https://forum.processing.org/two/discussion/26841/falling-balls )

TfGuy44

Have their size depend on their position.

If your balls is at a position (x,y), how far is that from the top?

How big does the ball need to be at the top?

How about at the bottom?

If you need more help, post your code. If you have none, attempt some and post the attempt. (Other people get really fussy about this...)

Chrisir

Didn't you like my previous explanation?

michyg

`Drop[] drops = new Drop[100];

void setup() { size(800, 800); for(int i = 0; i < drops.length; i++) { drops[i] = new Drop(); } }

void draw() { background(0); for(int i = 0; i < drops.length; i++) { drops[i].fall(); drops[i].show(); } }

class Drop { float x = random(width); float y = random(-500, -50); float yspeed = random (1, 6); float radius = 7; boolean bDead; void fall() { y = y + yspeed; yspeed = yspeed + 0.00005;

if(y > height) { y = random(-200,-100);

} }

void show() { stroke(255); ellipse( x, y, 20, 20); radius = radius - 0.05; if(radius <= 0) { bDead =true; println("dead"); } } }

`

Chrisir

not bad at all!

you need to use radius in the ellipse command please

Chrisir

you don't check bdead yet.

to do so make a backward for loop over the arrayList in draw and if bdead is true, remove(i)

btw not sure what bdead is initially, you want to say boolean bdead =false; where you declare it

michyg

` ellipse( x, y, radius, radius); radius = radius - 0.05;

` ok but i want to make the ball that falls big then smaller not that the balls first are all small and then get bigger. when they fall the need to gradually get smaller every time

michyg

like when you see something from really close the you star going away from it

Chrisir

they get smaller, starting at 7. if you want, replace 7 with 37

michyg

ok now i need to make them all of a different color bu if i but `void show() { fill(random(255),random(255), random(255));

stroke(255);
ellipse( x, y, radius, radius);
radius = radius -0.05;

}` every ball changes color. how do i make them all different colors

koogs

please don't post duplicates.

please learn how to format code.

Chrisir

at the start of the class

class Drop { 

    color colorDrop = color (random(255),random(255), random(255)); // !!!!

    float x = random(width); 

use the color here:

stroke(colorDrop );  // !!!!!!
ellipse( x, y, radius, radius);
radius = radius -0.05;

michyg

to make it bounce off the bottom what do i do?

Chrisir

Good progress here!

see here please

https://www.processing.org/examples/bounce.html

michyg

Drop[] drops = new Drop[100]; float ypos; float yspeed = 2.2; int ydirection = 1; int rad =60; void setup() { size(800, 800); for(int i = 0; i < drops.length; i++) { drops[i] = new Drop(); } ypos = height/2; } void draw() { background(36, 94, 80); for(int i = 0; i < drops.length; i++) { drops[i].fall(); drops[i].show(); } if (ypos > height-rad) { ydirection *= -1;} }

Chrisir

post also the class, we need the entire code

this must obviously be in the class, hm?

if (ypos > height-rad || ypos < rad) {
    ydirection *= -1;}
}

michyg

yea in which part of the class ?

Chrisir

why not in show() ?

Chrisir

You must declare the variables that are new where the others are declared inside the class

The new commands in show()

Understand the principle of the example, don’t just copy the lines

You have to change the variable names anyway

michyg

ArrayList<PVector> pos; ArrayList<PVector> vel; ArrayList<PVector> size; boolean a=false; color c; //PVector gravity; //int d = 30; void setup() { size(800,800); background(0); c = color (random(255),random(255), random(255)); init(); } void draw() { background(0); for(int i = 0; i < pos.size(); i++) { PVector p = pos.get(i); PVector v = vel.get(i); PVector s = size.get(i); ellipse(p.x, p.y , s.x, s.x); fill(c * i); p.add(v); if (p.y > height) { // println("funziona"); v.y = v.y * -1; p.y = height; a = true; } if (p.y < (height - 50) && v.y < 0 && a==true ) { v.y = v.y * -0.5; //println(p.y); } } particles(); } void init() { pos = new ArrayList<PVector>(); vel = new ArrayList<PVector>(); size = new ArrayList<PVector>(); } void particles() { PVector rndVel = new PVector(0, random(4,6)); vel.add(rndVel); PVector rndPos = new PVector(random(0,width) ,0); pos.add(rndPos); PVector rndSize = new PVector(random(10,15), random(10,15)); size.add(rndSize); }

Chrisir

Looks good!

Does it work?

Solution with a class would have been better but never mind

michyg

it works the only thig is that when it bounces off it needs to fade out but if i put an AlphaValue all the balls fade from the beginning not just when they touch the ground

Chrisir

if i put an AlphaValue all the balls fade from the beginning

instead of using a class, you took a step back and work with parallel arrays now, which is ok

but that means that parallel to

ArrayList size;

you need also an ArrayList with the fade value as int and with the information whether if ball is fading

Chrisir

here is a example for bouncing with gravity

Ball ball;

void setup() {
  size(1200, 860);

  ball = new Ball(111, 420, 40);
  noStroke();
  fill(255);
}

void draw() {
  background(0);

  //  text("Hit any key to jump", 322, 122);

  ball.move();
  ball.display();
}

// ---------------------------------------------------------------
// Input 

void keyPressed() {
  ball.jump();
}

// ================================================================

class Ball {

  float x, y; // position 

  float diameter; //  

  float xadd = 3.4;  // movement / vel 
  float yadd = 4;

  float gravity = 0.53; // Gravity 

  // Constructor
  Ball(float x_in, float y_in, 
    float diameter_in) {

    x = x_in;
    y = y_in;

    diameter = diameter_in;
  }// Constructor 

  void move() {

    // Ball move 

    // gravity changes yadd
    yadd += gravity;

    // move 
    x += xadd;
    y += yadd;

    // When hitting ground 
    if (y + diameter/2 > height) {
      y = height - diameter/2; // fix position  
      yadd=-abs(yadd)*.88; // bounce and damping 
      if (abs(yadd)<0.031) {  
        // full stop 
        xadd=0;
        yadd=0;
      }
    }//if

    // When hitting wall right
    if (x + diameter/2 > width) {
      xadd=-abs(xadd); // bounce
    }//if

    // When hitting wall left
    if (x - diameter/2 < 0) {
      xadd=abs(xadd); // bounce
    }//if
    //
    //
  }// function 

  void jump() {
    // Inits a jump
    yadd = -12.3;  // high negative yadd
  }// function 

  void display() {
    // Ball draw  
    ellipse(x, y, diameter, diameter);
  }// function 
  //
}//class
//