// =========================================================================
// Markus Lerner
// http://www.markuslerner.com
// 2003-10-29
//
// Dynamic Form: Order
// =========================================================================

int hNum = 20;
int vNum = 20;
float hBounds = 15;
float vBounds = 15;
float shiftX = 0;
float shiftY = 0;
Vec2D mouse;

Particle p[][];

void setup() {
  size(300, 300);
  background(0);
  smooth();
  framerate(30);
  ellipseMode(CENTER_DIAMETER);
  rectMode(CENTER_DIAMETER);

  mouse = new Vec2D();

  p = new Particle[hNum][vNum];

  int id = 0;
  for(int i=0; i<hNum; i++) {
    for(int j=0; j<vNum; j++) {
      p[i][j] = new Particle(i*(width-2*hBounds)/(hNum-1), j*(height-2*vBounds)/(vNum-1), id);
	  id++;
	}
  }
}

void loop() {
	mouse.set(mouseX, mouseY);
  background(0);
  translate(hBounds,vBounds);

	if(mouse.x != 0 && mouse.y != 0) {
	  shiftX += (mouse.x-width/2) /100;
	  if(shiftX > 2*PI) {
		  shiftX -= 2*PI;
	  }
	  shiftY += (mouse.y-height/2) /100;
	  if(shiftY > 2*PI) {
		  shiftY -= 2*PI;
	  }
  }

  for(int i=0; i<hNum; i++) {
    for(int j=0; j<vNum; j++) {
      p[i][j].loop();
	}
  }
}

class Particle {
	float x, y;
	int id;
	float size;

	Particle(float _x, float _y, int _id) {
		x = _x;
		y = _y;
		id = _id;
	}
	void loop() {
		size = sin(x*0.05 - shiftX) + sin(y*0.05 - shiftY) + 2;
		size *= 4;
		draw();
	}
	void draw() {
		noStroke();
		ellipse(x,y, size,size);
	}
}
// General vector class for 2D vectors =====================================
class Vec2D {
  float x,y;

  // Constructor with no parameters
  Vec2D() {
    x=0;
    y=0;
  }

  Vec2D(float _x,float _y) {
    x=_x;
    y=_y;
  }

  Vec2D(Vec2D v) {
    x=v.x;
    y=v.y;
  }

  void set(float _x,float _y) {
    x=_x;
    y=_y;
  }

  void set(Vec2D v) {
    x=v.x;
    y=v.y;
  }

  void add(float _x,float _y) {
    x+=_x;
    y+=_y;
  }

  void add(Vec2D v) {
    x+=v.x;
    y+=v.y;
  }

  void sub(float _x,float _y) {
    x-=_x;
    y-=_y;
  }

  void sub(Vec2D v) {
    x-=v.x;
    y-=v.y;
  }

  void mult(float m) {
    x*=m;
    y*=m;
  }

  void div(float m) {
    x/=m;
    y/=m;
  }

  float length() {
    return sqrt(x*x+y*y);
  }

  float angle() {
    return atan2(y,x);
  }

  void normalise() {
    float l=length();
    if(l!=0) {
      x/=l;
      y/=l;
    }
  }

  Vec2D tangent() {
    return new Vec2D(-y,x);
  }

  void rotate(float val) {
    // Due to float not being precise enough, double is used for the calculations
    double cosval=Math.cos(val);
    double sinval=Math.sin(val);
    double tmpx=x*cosval - y*sinval;
    double tmpy=x*sinval + y*cosval;

    x=(float)tmpx;
    y=(float)tmpy;
  }
}