import mathematik.*;

import teilchen.test.cubicle.*;
import teilchen.integration.*;
import verhalten.*;
import teilchen.*;
import verhalten.view.*;
import teilchen.test.particle.behavior.*;
import teilchen.behavior.*;
import teilchen.demo.*;
import teilchen.test.particle.springs.*;
import teilchen.gestalt.test.*;
import teilchen.cubicle.*;
import verhalten.test.*;
import teilchen.force.flowfield.*;
import teilchen.test.particle.*;
import teilchen.gestalt.util.*;
import teilchen.constraint.*;
import teilchen.force.vectorfield.*;
import teilchen.force.*;
import teilchen.util.*;

import mathematik.*;

import teilchen.Physics;
import teilchen.force.Attractor;
import teilchen.force.Gravity;
import teilchen.force.Spring;
import teilchen.force.ViscousDrag;
import teilchen.integration.RungeKutta;
import teilchen.util.Overlap;
import teilchen.util.StickMan;



/**
 * this demo shows some advanced use of particles, springs and attractors to create stickmen.
 */

Physics mPhysics;

Attractor mAttractor;

Gravity mGravity;

ViscousDrag mViscousDrag;

StickMan[] mMyStickMan;

void setup() {
  size(640, 480, OPENGL);
  smooth();
  frameRate(60);
  noFill();

  mPhysics = new Physics();
  mPhysics.setInegratorRef(new RungeKutta());

  mGravity = new Gravity();
  mGravity.force().y = 20;
  mPhysics.add(mGravity);

  mViscousDrag = new ViscousDrag();
  mViscousDrag.coefficient = 0.85f;
  mPhysics.add(mViscousDrag);

  mAttractor = new Attractor();
  mAttractor.radius(500);
  mAttractor.strength(0);
  mAttractor.position().set(width / 2, height / 2);
  mPhysics.add(mAttractor);

  mMyStickMan = new StickMan[20];
  for (int i = 0; i < mMyStickMan.length; i++) {
    mMyStickMan[i] = new StickMan(mPhysics, random(0, width), random(0.3f, 0.6f));
  }
}

void draw() {

  mPhysics.step(1f / 60f);
  Overlap.resolveOverlap(mPhysics.particles());

  /* constraint particles */
  for (int i = 0; i < mPhysics.particles().size(); i++) {
    if (mPhysics.particles(i).position().y > height - 10) {
      mPhysics.particles(i).position().y = height - 10;
    }
    if (mPhysics.particles(i).position().x > width) {
      mPhysics.particles(i).position().x = width;
    }
    if (mPhysics.particles(i).position().x < 0) {
      mPhysics.particles(i).position().x = 0;
    }
  }

  /* handle particles */
  if (mousePressed) {
    mAttractor.position().set(mouseX, mouseY);
    if (mouseButton == RIGHT) {
      mAttractor.strength(-500);
      mAttractor.radius(500);
    } 
    else {
      mAttractor.strength(500);
      mAttractor.radius(100);
    }
  } 
  else {
    mAttractor.strength(0);
  }

  if (keyPressed) {
    mGravity.force().y = -10;
  } 
  else {
    mGravity.force().y = 20;
  }

  /* draw */
  background(255);

  /* draw springs */
  stroke(0, 20);
  for (int i = 0; i < mPhysics.forces().size(); i++) {
    if (mPhysics.forces(i) instanceof Spring) {
      Spring mySpring = (Spring)mPhysics.forces(i);
      line(mySpring.a().position().x, 
      mySpring.a().position().y, 
      mySpring.b().position().x, 
      mySpring.b().position().y);
    }
  }

  /* draw particles */
  for (int i = 0; i < mPhysics.particles().size(); i++) {
    ellipse(mPhysics.particles(i).position().x, 
    mPhysics.particles(i).position().y, 5, 5);
  }

  /* draw man */
  for (int i = 0; i < mMyStickMan.length; i++) {
    mMyStickMan[i].draw(g);
  }
}