Lines are freaking out

smalty

in Contributed Library Questions • 2 years ago

Hello,

I am going for a kind of flying-through-space effect with random-colored lines, and I've basically got it, but if I set the "timer" variable too high, I get like an overload of lines and a bunch of random lines intersecting the origin are randomly drawn. The structure of the code is this; there is a class called "littlelight" which are the individual lines erupting from the origin. That class is called every frame--and every frame a new "littlelight" is generated by "ps" which is an instance of the ParticleSystem class. The ParticleSystem class removes "littlelight"'s from the ArrayList when their "timer" has run out. The "timer" is set to run to zero about when that "littlelight" is entirely off-screen; so, once a "littlelight" leaves the screen area, it dies. However, I really have no idea where this overload behavior is coming from.

This uses toxic libs btw. The code is set now to overload as I have described above. If you go down to where the "timer" variable is set, you will see I have commented code that will work.

This code is based on this example from the Processing website. http://processing.org/learning/topics/simpleparticlesystem.html

Thanks

import toxi.geom.*;
ParticleSystem ps;

void setup ()
{
size(1280, 720, P3D);
frameRate(30);
translate(width/2, height/2);
ps = new ParticleSystem(1, new Vec3D(0, 0, 0));
//smooth();
}

void draw() {
translate(width/2, height/2);
background(0);
ps.run();
ps.addlittlelight(0, 0);
noStroke();
translate(-width/2, -height/2);
}

class ParticleSystem {

//GLOBAL VARIABLES
ArrayList particles;   // An arraylist for all the particles
Vec3D origin;          // An origin point for where particles are born

    //CONSTRUCTOR
ParticleSystem(int num, Vec3D v) {
    particles = new ArrayList();     // Initialize the arraylist
    origin = v;                      // Store the origin point
    // Add "num" amount of particles to the arraylist
    //for (int i = 0; i < num; i++) {
      //particles.add(new littlelight(origin));
    //}
}

//FUNCTIONS
void run() {
    for (int i = particles.size() - 1; i>=0; i--) {
      littlelight p = (littlelight) particles.get(i);
      //p.run();
      if (p.dead()) {
        particles.remove(i);
      }
      else p.run();
    }
}

/*
void addlittlelight() {
   particles.add(new littlelight(origin));
   }
   */

void addlittlelight(float x, float y) {
    particles.add(new littlelight(new Vec3D(x, y, 0)));
}

/*
void addlittlelight(littlelight p) {
   particles.add(p);
   }
   */

boolean dead() {
    if (particles.isEmpty()) {
      return true;
    }
    else
    {
      return false;
    }
}
}

class littlelight {

//GLOBAL VARIABLES
Vec3D loc;
Vec3D loc2;
Vec3D vel = new Vec3D(random(-1, 1), random(-1, 1), random(0.9, 0.99));
Vec3D acc;
float r;
float timer;
float colorr = random(0, 255);
float colorg = random(0, 255);
float colorb = random(0, 255);
float len = 100;

//CONSTRUCTOR
littlelight(Vec3D l) {
    //vel = new Vec3D(random(-1, 1), random(-1, 1), random(0.9, 0.99));
    acc = vel.copy();
    acc.normalizeTo(1);
    loc = l;
    loc2 = vel.copy();
    loc2.normalizeTo(len);
    //loc2.normalizeTo(len);
    timer = 100.0;
    //try this
    //timer = 30.0;
}

//FUNCTIONS
void run() {
    update();
    render();
}

void update() {
    vel.addSelf(acc);
    loc.addSelf(vel);
    loc2.addSelf(vel);
    timer -= 1.0;
}

void render() {
    //noStroke();
    if (timer > -1.0) {
      strokeWeight(1);
      stroke(colorr, colorg, colorb);
      //Line3D boner = new Line3D(loc, loc2);
      line(loc.x, loc.y, loc.z, loc2.x, loc2.y, loc2.z);
      //strokeWeight(10);
      //stroke(255, 0, 0);
      //point(loc.x, loc.y, loc.z);
      //stroke(0, 0, 255);
      //point(loc2.x, loc2.y, loc2.z);
      //ellipse(loc.x, loc.y, r * (1000 - timer), r * (1000 - timer));
      //x = Line3D(loc, loc2);
    }
}

boolean dead() {
    if (timer <= 0.0) {
      return true;
    }
    else {
      return false;
    }
}
}

Replies(6)

amnon.owed

Re: Lines are freaking out

2 years ago

The freakiness is caused by freaky location values. Use println to see them. The quick solution is to dampen the effects of location a bit through the render function. For example, like so...

import toxi.geom.*;
ParticleSystem ps;
void setup () {
size(1280, 720, P3D);
ps = new ParticleSystem(1, new Vec3D(0, 0, 0));
frameRate(30);
}
void draw() {
translate(width/2, height/2);
background(0);
ps.run();
ps.addlittlelight(0, 0);
}
class ParticleSystem {
ArrayList particles;
Vec3D origin;
ParticleSystem(int num, Vec3D v) {
particles = new ArrayList();
origin = v;
}
void run() {
for (int i = particles.size()-1; i>=0; i--) {
littlelight p = (littlelight) particles.get(i);
if (p.dead()) {
particles.remove(i);
} else {
p.run();
}
}
}
void addlittlelight(float x, float y) {
particles.add(new littlelight(new Vec3D(x, y, 0)));
}
}
class littlelight {
Vec3D loc;
Vec3D loc2;
Vec3D vel;
Vec3D acc;
float r;
float timer;
float colorr = random(0, 255);
float colorg = random(0, 255);
float colorb = random(0, 255);
float len = 100;
littlelight(Vec3D l) {
vel = new Vec3D(random(-1, 1), random(-1, 1), random(0.9, 0.99)); // another work-around is to set z to 0
acc = vel.copy();
acc.normalizeTo(1);
loc = l;
loc2 = vel.copy();
loc2.normalizeTo(len);
timer = 100;
}
void run() {
update();
render();
}
void update() {
vel.addSelf(acc);
loc.addSelf(vel);
loc2.addSelf(vel);
timer -= 1.0;
}
void render() {
if (timer > -1.0 && abs(loc.z) < 500) { // don't render if location gets to crazy
strokeWeight(1);
stroke(colorr, colorg, colorb);
line(loc.x, loc.y, loc.z, loc2.x, loc2.y, loc2.z);
}
}
boolean dead() {
if (timer <= 0.0) {
return true;
} else {
return false;
}
}
}

smalty

Re: Re: Lines are freaking out

2 years ago

Thanks way much. As I understand it then, in this specific sketch when a line gets too close to Processing's "camera" it produces artifacts such as we saw?

amnon.owed

Re: Lines are freaking out

2 years ago

There is some truth in that. The problem does surface when lines are close to the camera. Processing's camera in this sketch is around z coordinate 625, and littlelights with z coordinates of approximately 500 up to 625 are the ones that cause unintended lines. However, they're just lines given the generated coordinates, so I don't think artifacts is an accurate description.

I gave the quick solution earlier, which in all fairness fixes the symptoms rather than the cause of the problem. The long-term solution could be to:

Tweak the littlelight dead function so littlelights are removed immediately when they go off-screen. A quick check tells me that littlelights seem to have over 50 off-screen (a small fraction of which are unintended on-screen) frames before they are removed. Accurate removal will prevent the problem.
Tweak the littlelight update function so the coordinates are better controlled. Right now they generate unwanted / unpredictable coordinates, which in some combinations causes lines to enter the screen again. So shape the possible trajectories more carefully. Of course there are different ways to do this.

While working on a solution and/or finding problems, you could move the addlittlelight or the littlelight's update function to a keyPressed function so you can generate and move them one at a time. And as mentioned before, the best way to find problems and solutions is to gather information about what happens in your program. Since println() is the best debug tool available to you, make sure to use it.

smalty

Re: Re: Lines are freaking out

2 years ago

Thanks again. Brilliant.

toxmeister

Re: Lines are freaking out

2 years ago

FYI this warping of 3D lines is only a problem with the P3D renderer. Switching to OPENGL will remove the issue since that uses proper camera clipping planes...

smalty

Re: Re: Lines are freaking out

2 years ago

Toxic,

Hi.

I like your libs. I'm presently coming to grips with toxi.geom and Vec3D, as well as Processing as whole.

I will consider Opengl when I do another sketch like this, but I read somewhere that P3D was generally better than Opengl, so I stuck with P3D for this sketch. I can't remember where I read that.

I was thinking about contacting you for your thoughts on the best way to do this sketch. You'll find the finished sketch below. I mapped the strokeWeight to the z location of the line to create a depth effect--making lines larger as they approach the camera. I like how it came out.

In broad strokes what do you think would be the best way to accomplish something like this using something like 3D cylinders instead of lines? I.e. what classes would be essential and how would the sketch be organized?

Finally, I just started with Processing about a month ago, and I just started with toxi.libs a few weeks ago. What are the most commonly used--and most useful--classes in toxi.libs? I know Vec3D of course, but I assume that there are a few other, very common, very useful classes which I am unaware of.

I appreciate your fine work on toxi.libs.

Sincerely,
Smalty

import toxi.geom.*;
//import processing.video.*;

//MovieMaker mm;

ParticleSystem ps;

void setup () {
size(1280, 720, P3D);
//mm = new MovieMaker(this, width, height, "throughspace.mov", 30, MovieMaker.ANIMATION, MovieMaker.LOSSLESS);
ps = new ParticleSystem(1, new Vec3D(0, 0, 0));
frameRate(30);
smooth();
}

void draw() {
translate(width/2, height/2);
background(0);
ps.run();
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
ps.addlittlelight(0, 0);
//mm.addFrame();
}

class ParticleSystem {
ArrayList particles;
Vec3D origin;

ParticleSystem(int num, Vec3D v) {
    particles = new ArrayList();
    origin = v;
}

void run() {
    for (int i = particles.size()-1; i>=0; i--) {
      littlelight p = (littlelight) particles.get(i);
      if (p.dead()) {
        particles.remove(i);
      } else {
        p.run();
      }
    }
}

void addlittlelight(float x, float y) {
    particles.add(new littlelight(new Vec3D(x, y, 0)));
}
}

class littlelight {
Vec3D loc;
Vec3D loc2;
Vec3D vel;
Vec3D acc;
float r;
float timer;
float colorr = random(0, 255);
float colorg = random(0, 255);
float colorb = random(0, 255);
float len = random(10, 50);

littlelight(Vec3D l) {
    vel = new Vec3D(random(-1, 1), random(-1, 1), random(0.3, 0.99)); // another work-around is to set z to 0
    acc = vel.copy();
    acc.normalizeTo(0.3);
    loc = l;
    loc2 = vel.copy();
    loc2.normalizeTo(len);
    timer = 300;
}

void run() {
    update();
    render();
}

void update() {
    vel.addSelf(acc);
    loc.addSelf(vel);
    loc2.addSelf(vel);
    timer -= 1.0;
}

void render() {
    if (timer > -1.0 && abs(loc.z) < 500) { // don't render if location gets to crazy
      strokeWeight(0.01 * loc.z);
      //stroke(colorr, colorg, colorb);
      stroke(254);
      line(loc.x, loc.y, loc.z, loc2.x, loc2.y, loc2.z);
    }
}

boolean dead() {
    if (timer <= 0.0) {
      return true;
    } else {
      return false;
    }
}
}

/*
void keyPressed() {
if (key == ' ') {
    mm.finish(); // Finish the movie if space bar is pressed!
}
}
*/