Using slider to change randomSeed

apa

Hi all, i'm trying to control a randomSeed() parameter with a slider to create a random number that i can use again in a running sketch, i'm having problems to change the randomSeed, it always get stucked, if i comment the line 31( "sliderValue= int(random(10));") it runs ok, but of course i don't have the random, here's the sketch:

import controlP5.*;

ControlP5 cp5;

//int sliderValue;
int caos, sliderValue;
color myColor;

void setup() {
  size(700, 400);
  noStroke();
  cp5 = new ControlP5(this);

  cp5.addSlider("sliderValue")
    .setPosition(100, 50)
      .setRange(0, 10)
        .setNumberOfTickMarks(10)
          ;

  cp5.addSlider("caos")
    .setPosition(100, 100)
      .setRange(0, 10)
        .setNumberOfTickMarks(10)
          ;
}

void draw() {
  background(0);

  randomSeed(caos);
  sliderValue= int(random(10));

  fill(map(sliderValue, 0, 10, 0, 255));
  rect(0, 0, width, 100);

  println("SLIDER VALUE", sliderValue);
  println("CAOS", caos);
}

void slider(float theColor) {
  myColor = color(theColor);
  println("a slider event. setting background to "+theColor);
}

GoToLoop

According to randomSeed()'s reference:
https://Processing.org/reference/randomSeed_.html

It resets random() back to a pre-determined sequence of pseudo-random values.
You should execute randomSeed() when the slider's value is changed rather than each single draw().

apa

Hi, thanks for your answer, i've tryied that, maybe i'm missing something, here's the code:

import controlP5.*;
ControlP5 cp5;

int caos, sliderValue;
color myColor;

void setup() {
  size(700, 400);
  noStroke();
  cp5 = new ControlP5(this);

  cp5.addSlider("sliderValue")
    .setPosition(100, 50)
      .setRange(0, 10)
        .setNumberOfTickMarks(10)
          ;

  cp5.addSlider("caos")
    .setPosition(100, 100)
      .setRange(0, 10)
        .setNumberOfTickMarks(10)
          ;
}

void draw() {
  background(0);

  fill(map(sliderValue, 0, 10, 0, 255));
  println(sliderValue);
  rect(0, 0, width, 100);
}

public void caos(int theValue) {
  randomSeed(theValue);
  int r = int(random(100));
  sliderValue = r;

  println("CAOS", theValue);
  println("r", r);
}

public void sliderValue(int theValue) {
  sliderValue = theValue;
  println("SLIDER", theValue);
}

GoToLoop

I said you should only change randomSeed() when the "seed" actually changes.
I didn't mention anything about not using random() itself! :-<

_vk

I thought the seed was only good to repeat a serie of pseudo-random each time the program runs. How this works during runtime?

from reference:

Sets the seed value for random(). By default, random() produces different results each time the program is run. Set the seed parameter to a constant to return the same pseudo-random numbers each time the software is run.