Moving Snowflake

JamesKoo

Hi,

I have created Snowflake animation.

BGADII

Make a snowflake class and create an array of snowflake objects. Why not?

kfrajer

Check prev relevant posts: https://forum.processing.org/two/search?Search=raining

Kf

jeremydouglass

You might be interested in some of the reference Example sketches online: things like clicking to create multiple falling objects, particle systems, etc.

• https://processing.org/examples/arraylistclass.html
• https://processing.org/examples/simpleparticlesystem.html
• https://processing.org/examples/multipleparticlesystems.html

JamesKoo

Currently in my setup(), I have set the size, background, stroke and a for loop to get the final state of the object after substituting the rule into the turtle.

for(int k = 0; k < L; k++){ state = substitute(state, ruleF); }

How can I make it into an array?

kfrajer

the final state of the object after substituting the rule into the turtle.

It is not clear what you are asking. Please remember we don't know anything about your code unless you explicitly show it to us so to be able to understand what you are trying to do. This is a good opportunity to check what a MCVE is: https://stackoverflow.com/help/mcve

Kf

jeremydouglass

@JamesKoo -- yes, this is unclear. What is state? What is substitute()? What is ruleF? What is "the turtle"?

Share your code here -- you can format it for a forum post following these instructions: https://forum.processing.org/two/discussion/15473/how-to-format-code-and-text

Chrisir

here is a example to place two snowflakes

LSystem[] ps=new LSystem[2];

void setup() {
  size(640, 360);
  ps[0] = new LSystem();
  ps[0].simulate(3);
  ps[1] = new LSystem();
  ps[1].simulate(3);
}

void draw() {
  // background(0);
  ps[0].render();
  ps[1].render();
}

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

class LSystem {

  int steps = 12;

  String axiom;
  String rule;
  String production;

  float startLength=100;
  float drawLength;
  float theta;

  int generations;

  float x=random(width-44), y=random(height-44);

  LSystem() {

    axiom = "F";
    rule = "F+F";
    startLength = 90.0;
    theta = radians(120.0);
    reset();
  }

  void reset() {
    production = axiom;
    drawLength = startLength;
    generations = 0;
  }

  int getAge() {
    return generations;
  }

  void render() {
    translate(x, y);
    steps += 5;          
    if (steps > production.length()) {
      steps = production.length();
    }
    for (int i = 0; i < steps; i++) {
      char step = production.charAt(i);
      if (step == 'F') {
        fill(255);
        rect(0, 0, -drawLength, -drawLength);
        noFill();
        translate(0, -drawLength);
      } else if (step == '+') {
        rotate(theta);
      } else if (step == '-') {
        rotate(-theta);
      } else if (step == '[') {
        pushMatrix();
      } else if (step == ']') {
        popMatrix();
      }
    }
  }

  void simulate(int gen) {
    while (getAge() < gen) {
      production = iterate(production, rule);
    }
  }

  String iterate(String prod_, String rule_) {
    drawLength = drawLength * 0.6;
    generations++;
    String newProduction = prod_;          
    newProduction = newProduction.replaceAll("F", rule_);
    return newProduction;
  }
  //
}
//

JamesKoo

Currently I have create a snowflakes class file, but unable to make it into an array to redraw it randomly.

tes[] flakes = new tes[100];

void setup() {
  size(600, 400);
  background(255);
  stroke(0);
  flakes[i] = new tes();
}

void draw() {
  background(255);
  //tes flakes = new tes();
  y = y + speed;
  if (y>height+100) {
    y = -10;
    L = 3; //Set value of L back to 3 when it redraw.
  }
  //flakes.animate();
  //flakes.display();
  for (int i =0; i<100; i++) {
    flakes[i].draw();
    flakes[i].mouseClicked();
  }
}


----------------------------------------------------
  tes class file


int SD = 5, sd = SD/2;
float d = sd;
float angle = PI/3;
String state = "[F+F+F+F+F]";
String ruleF = "F-F++F-F";
float L = 3;
float fade = 1;
float speed = random(1, 5);
float x = random(0, 600);
float y = 100;

public class tes {

  void draw() {
    pushMatrix();
    fade++;
    stroke(fade, 255);
      for (int k = 0; k < L; k++) {
        state = substitute(state, ruleF);
      }
    }
    single();
    popMatrix();
  }

  void mouseClicked() {
    L=L-1;
  }

  void single() {
    translate(x, y);
    for (int i =0; i < state.length(); i++)
      turtle(state.charAt(i));
  }

}

How can i change it to an array of snowflakes?

Chrisir

I demonstrated that above with LSystem class

Move this line

  tes flakes = new tes();

before setup

And change it to

 tes[] flakes=new tes[100];

Now in setup() use a for loop similar to my setup

Inside the for loop

flakes[i] = new tes(......

in draw also use a for loop and then similar to my draw () above

flakes[i].render();

JamesKoo

I have just did some adjustment on my codes on top, is that what you mean?

Chrisir

Does it work?

Does it do what you want?

Chrisir

You are almost there

You need this in setup() too :

for(int i =0; i<100;i++)

Before flakes[....

Do you know why?

;-)

JamesKoo

I edited the codes on my phone, have yet to try it out yet. I don't have my computer with my currently.

If not, it will generate only one flakes right?

Chrisir

It will crash

Chrisir

You need to make additional changes too:

• Since all the snowflakes should have different positions you need to move x,y inside the class

• So each snowflake is individual

• In fact move all or as much as you can of the global variables inside the class

Remark

It would be cool to have different types of flakes, maybe you can vary the rule for each but that’s for later

JamesKoo

Currently my number of iteration is set to 3, also know as the value "L". I tried to add on a mouseClicked() function to decrease the number of iteration. However when I clicked on my mouse, the value of L decrease to 2 but it doesn't update the value of L in the display() of the class file. May i know where have i gone wrong?

Chrisir

post your entire code to check

Chrisir

Is L a variable inside the class or a global one?

JamesKoo

Currently it is global. I update it on 9th post on top.

Chrisir

in setup() use a for loop similar to my setup

Inside the for loop

flakes[i] = new tes(......

in draw also use a for loop and then similar to my draw () above

flakes[i].render();

Chrisir

you haven't moved the variables inside the class as I told you

also better post the entire code a the bottom of the discussion as new post and not edit old posts, because then my remarks about the code don't make sense anymore...

and the whole discussion is just confusing

Chrisir

I got a running version with 100 flakes.

Do you have that too?

(no mouseClicked() function or L change)

JamesKoo

I have shift it to a new discussion to avoid further confusion. Sorry about that.

JamesKoo

Could you pm me on that? I would like to see the different.

Chrisir

Why did you start a new discussion? Pointless. Even more so since in the new discussion your code is not runnable. Bad.

Question:

I got a running version with 100 flakes.

Do you have that too?

JamesKoo

So what do i do currently? Update this post?

JamesKoo

100 snowflakes running with the lsystem?

Chrisir

start by answer my question

Chrisir

post your entire sketch here.

a runnable version

when you want to change L what do you want to achieve in the graphic?