Each particle system with a different color?

selmabrd

Hello creative coders ! I am learning processing, and am working a code with multiple particle systems.

I used kind of the same structure as dans shifman's nature of code example, system of systems, in which a new particle system appears when you click the mouse (see code here)

I want to do something kind of simple. Everytime i click the mouse, a particle system of a different color appears.

My color is defined in the Particle class with a function using noise :

  void col(){
    colorMode(HSB, 360, 100, 100);
    c = map(noise(ct), 0, 1, 140, 360);
    ct-= 0.05;

  }

Should I work it here or in the ParticleSystem class? In words, how can I do this?

Lord_of_the_Galaxy

Allow the Particle class to store its own color in a variable. And this variable should be initialised inside the constructor. The constructor should therefore have an additional color argument.

BTW, the code you have given is quite stupid - line 3 does nothing at all.

selmabrd

Sorry, I corrected it. But ignore it. In shifman's example.. I would declare a new variable in the particlesystem class like : particles.add(new Particle(origin, sysCol));

class Particle {
  PVector position;
  PVector velocity;
  PVector acceleration;
  float lifespan;

  Particle(PVector l, float col) {
    acceleration = new PVector(0,0.05);
    velocity = new PVector(random(-1,1),random(-2,0));
    position = l.get();
    lifespan = 255.0;
  }

To display it :

void display() {
  fill(col);
  ellipse(position.x,position.y,12,12);
}

But if I put col = random(255); to have a random greyscale value here, every particle would have a different color. I guess It needs to be in the ParticleSystem class.

What I don't get is how modify/use a variable from a class to another. Sorry im just getting started

xxMrPHDxx

You should have the color for the particle store like this:-

class Particle {
  PVector position;
  PVector velocity;
  PVector acceleration;
  float lifespan;
  float col;

  Particle(PVector l, float col) {
    acceleration = new PVector(0,0.05);
    velocity = new PVector(random(-1,1),random(-2,0));
    position = l.get();
    lifespan = 255.0;
    this.col = col;
  }
}

Lord_of_the_Galaxy

Yes, @xxMrPHDxx you're probably right. But the OP's comments are a bit unclear, so the exact implementation may be different.

selmabrd

Yay thank you both ! Had no idea aboutthis.

Lord_of_the_Galaxy

Then research about it, it's important.

jeremydouglass

https://processing.org/reference/this.html

Using this is often unnecessary / redundant, but it can add clarity.

Lord_of_the_Galaxy

But sometimes it's better/nescessary to use this because there's just no other way for a variable to pass itself into a function, if you understand me.