Putting point object into new ArrayList, when coordintes are equal

petras_vestartas

Hi,

I have a question about two ArrayLists of my script.

There are two ArraLists:

for(int i = 0; i < inputPolys.size(); i++){
            WB_Polygon2D a = inputPolys.get(i);
            for(int j = 0; j < a.points.length; j++ ){
            pointsInput1.add(a.points[j]);
            }//for
        }//for

for(int i = 0; i < intersectPolys.size(); i++){
            WB_Polygon2D a = intersectPolys.get(i);
            for(int j = 0; j < a.points.length; j++ ){
            pointsInput2.add(a.points[j]);
            }//for
        }//for

The script is dealing with polygons - inputPolys and intersected polygons - intersectPolys. There are N polygons in inputPolys, and from 0 to n-1 polygons in intersectPolys ArrayList (this arrayList changes each frame - the number of objects changes).

What I am doing in these double for() loops is getting the points of polygons and adding them to new ArrayLists
a) pointsInput1 - for inputPolys polygons
b) pointsInput2 - for changing intersectPolys polygons.

Then I want two compare if the location of pointsInput1 (a.points[i].x, a.points[i].y) and pointsInput2(b.points[j].x, b.points[j].y) are the same.

But this is the problem I have.

How to write a code when I want to compare one point of first arraylist with all the other points from second arrayList?

Thanks, Petras

GoToLoop

Although it got nothing to do w/ your code, I think the algorithm used from the code below
to determine whether a Dot is near to each other can be food for thought: :-\"

/** 
 * Moving Dots (v2.26)
 * by Josem.93 (2013/Aug)
 * mod GoToLoop
 * 
 * forum.processing.org/topic/interaction-among-objects-in-an-array
 * forum.processing.org/topic/gradual-movement-within-a-for-loop
 * 
 * studio.processingtogether.com/sp/pad/export/ro.9s0026dE7B8v-/latest
 */

final static int NUM = 30, FPS = 60;
final static Dot[] dots = new Dot[NUM];

boolean isPaused;

void setup() {
  size(800, 600);
  frameRate(FPS);
  noSmooth();
  stroke(Dot.COLOUR);
  fill(Dot.COLOUR);

  for (int i = 0; i != NUM; dots[i++] = new Dot());
}

void draw() {
  background(-1);
  for (int i = 0; i != NUM; connectPoints(i++))   dots[i].script();
}

void mousePressed() {
  if (isPaused = !isPaused)   noLoop();
  else                          loop();
}

void keyTyped() {
  mousePressed();
}

final static void connectPoints(int i) {
  for (int z = i+1; z != NUM; z++)
    if ( dots[i].isNear(dots[z]) )   dots[i].drawLine(dots[z]);
}

class Dot {
  final static short DIM = 5, MIN_DIST = 30, MAX_SPD = 5;
  final static color COLOUR = 0100;

  float x, y;
  float spx = random(-MAX_SPD, MAX_SPD);
  float spy = random(-MAX_SPD, MAX_SPD);

  Dot() {
    x = width>>1;
    y = height>>1;
  }

  void script() {
    move();
    display();
  }

  void move() {
    if ((x += spx) > width  | x < 0)  spx *= -1;
    if ((y += spy) > height | y < 0)  spy *= -1;
  }

  void display() {
    ellipse(x, y, DIM, DIM);
  }

  boolean isNear(Dot other) {
    //return dist(x, y, other.x, other.y) < MIN_DIST;
    return sq(other.x - x) + sq(other.y - y) < MIN_DIST*MIN_DIST;
    //return abs(other.x - x) < MIN_DIST && abs(other.y - y) < MIN_DIST;
  }

  void drawLine(Dot other) {
    line(x, y, other.x, other.y);
  }
}

petras_vestartas

Dear GoToLoop,

I see that the script you posted is dealing with class Dot. Maybe this is a problem I have as I am not very good at using classes.

Could you review my script? It is actually all about ArrayLists and it uses Hemesh library. At top of the script there are 3 triangles initialized, then they are put into inputPolys ArrayList, then intersected polygons are put into intersectPolys ArrayList.

Then I am dealing with the current problem of comparing points of each list. I found the idea how to compare if each point is in the same location. You could look at function called "substractManyfromOne". But still happened another problem. I got at the same time 9 outcomes (not 1 as I need) in the arrayList "inputPoints3" --> the outcome is showed on display by println function. This happened because, there is for loop that is changing like that (1 object, 2 objects,... 9 objects).

Do you know how to solve it?

import processing.core.PApplet;
import wblut.math.*;
import wblut.processing.*;
import wblut.core.*;
import wblut.hemesh.*;
import wblut.geom.*;

import java.util.ArrayList;
import java.util.List;

WB_Render render;

public void setup() {

  size(1280, 720, OPENGL);
  smooth();

  render = new WB_Render(this);
}// setup

public void draw() {

  background(255);
  noStroke();
  noFill();

  int dim = 200;

  //ArrayList of inputpolys
  ArrayList<WB_Polygon2D> inputPolys = new ArrayList<WB_Polygon2D>();
  ArrayList<WB_Point2d> points = new ArrayList<WB_Point2d>();

  // Initialize inputPoly 1
  points.add(new WB_Point2d(width / 2, height / 3 - dim));
  points.add(new WB_Point2d(width / 2 + dim, height / 2 + dim / 2));
  points.add(new WB_Point2d(width / 2 - dim, height / 2 + dim / 2));
  inputPolys.add(new WB_Polygon2D(points));
  // clear points
  points.clear();
  // Initialize inputPoly 2
  points.add(new WB_Point2d(mouseX, mouseY - dim));
  points.add(new WB_Point2d(mouseX + dim, mouseY + dim / 2));
  points.add(new WB_Point2d(mouseX - dim, mouseY + dim / 2));
  inputPolys.add(new WB_Polygon2D(points));
  // clear points
  points.clear();
  // Initialize inputPoly 3
  points.add(new WB_Point2d(width / 4, height / 3 - dim));
  points.add(new WB_Point2d(width / 5 + dim, height / 5 + dim / 2));
  points.add(new WB_Point2d(width / 5 - dim, height / 5 + dim / 2));
  inputPolys.add(new WB_Polygon2D(points));
  // clear points
  points.clear();


  for (WB_Polygon2D p : inputPolys) {
    fill(0, 10);
    render.drawPolygon2D(p);
  }

  //end of inputpolys

  stroke(0);
  fill(0, 50);

  List <WB_Polygon2D> intersectPolys = new ArrayList <WB_Polygon2D>();
  List<WB_Point2d> pointsInput1 = new ArrayList <WB_Point2d>();
  List<WB_Point2d> pointsInput2 = new ArrayList <WB_Point2d>();
  List<WB_Point2d> pointsInput3 = new ArrayList <WB_Point2d>();
  List <WB_Polygon2D> polyBig = new ArrayList <WB_Polygon2D>();
  List <WB_Polygon2D> polySmall = new ArrayList <WB_Polygon2D>();
  List <WB_Polygon2D> polyTest = new ArrayList <WB_Polygon2D>();

  for (int i = 0; i < inputPolys.size(); i++) {
    WB_Polygon2D a = inputPolys.get(i);
    for (int j = i + 1; j < inputPolys.size(); j++) {
      WB_Polygon2D b = inputPolys.get(j);
      intersectPolys.addAll(WB_Polygon2D.intersection(a, b));
    }//for
  }//for

  for (int i = 0; i < inputPolys.size(); i++) {
    WB_Polygon2D a = inputPolys.get(i);
    for (int j = 0; j < a.points.length; j++ ) {
      pointsInput1.add(a.points[j]);
      polyBig.add(new WB_Polygon2D(pointsInput1));
    }//for
  }//for

  for (int i = 0; i < intersectPolys.size(); i++) {
    WB_Polygon2D a = intersectPolys.get(i);
    for (int j = 0; j < a.points.length; j++ ) {
      pointsInput2.add(a.points[j]);
      polySmall.add(new WB_Polygon2D(pointsInput2));
    }//for
  }//for

  for (int i = 0; i < pointsInput1.size(); i++) {
    pointsInput3.addAll(substractManyFromOne(pointsInput1.get(i), 
    pointsInput2));
    println("frameCount " + frameCount + " result " + pointsInput3);
    //polyTest.add((WB_Polygon2D) pointsInput3);
  }// for


  for (WB_Polygon2D p : polyTest) {
    render.drawPolygon2D(p);
  }//for

  stroke(0);
  fill(0, 10);

  for (WB_Polygon2D p : intersectPolys) {

    //render.drawPolygon2D(p);
    render.drawPolygon2DVertices(p, 5);
  }//for
  // end of intersectPolys
}// draw

List<WB_Point2d> substractManyFromOne(WB_Point2d inputPt, List<WB_Point2d> intPt) {
  // this will collect all the pieces that remain from "one" after subtracting "many"
  List<WB_Point2d> eachPtinputPt = new ArrayList<WB_Point2d>();
  //adding points (arraylist list grows like a,b,c,d,e,f,g,h,i points)
  eachPtinputPt.add(inputPt); 
  //println(eachPtinputPt);

  List <WB_Point2d> AllFragmentsMinusOther = new ArrayList <WB_Point2d> ();
  for (WB_Point2d EintPt:intPt) {//enter the intersection list

    for (WB_Point2d eachPt : eachPtinputPt) {

      if (EintPt.x == eachPt.x && EintPt.y == eachPt.y) {

        AllFragmentsMinusOther.add(EintPt);
      }
    }//for
  }//for
  //if(AllFragmentsMinusOther != null){
  return AllFragmentsMinusOther;
}// ArrayList substractManyFromOne  

GoToLoop

Dunno if I'd be able to help you on this. I'm not very good at using 3rd-party libraries yet! 3:-O
Anyways, to raise the chances for some1 to help you out, you should at least post your code well formatted! [..]
After posting it, select it and press the C button (4th button).

petras_vestartas

Actually, it does no have much with 3rd-party library Hemesh. As it is dealing with a few simple classes and functions. If you have the Hemesh or could install it and take a look how my script works, it would be a big help for me:)

Thanks.

petras_vestartas

Found it! Yes.