//boidsSimulation.java

import java.awt.*;

/**
* Boids Applet
* ボイドもどき
*
*@version	0.1 29 May 1996
*@author	Tasuku Gouda
*/
public class boidsSimulation extends java.applet.Applet implements Runnable{
	int width,height,bestDistance = 30,colorA = 0,colorB = 128;
	double maxSpeed = 15;
	double copyWait = 0.5;
	double centerWait = 0.5;
	double acceleration = 1.1;
	int LengthList[][];
	Boid ball[];
	boolean trail = false,debag = false;
	Thread t;
	double tempP_x[];
	double tempP_y[];
	double angleList[][];
	double visibleAngle = Math.PI / 2.0;
	double lastAngle[];

	private Image offScreenImage;
	private Graphics offScreenGraphics;

/**
* hypercard では open stack 相当
*/
	public void init(){
		Dimension r = size();
		String s;
		int max = 5;
		width = r.width;
		height = r.height;
		s = getParameter("boids");
		if ( s != null ){
			max = Integer.parseInt(s);
		}
		s = getParameter("max");
		if ( s != null ){
			maxSpeed = Double.valueOf(s).doubleValue();
		}
		s = getParameter("copyWait");
		if ( s != null ){
			copyWait = Double.valueOf(s).doubleValue();
		}
		s = getParameter("centerWait");
		if ( s != null ){
			centerWait = Double.valueOf(s).doubleValue();
		}
		s = getParameter("acceleration");
		if ( s != null ){
			acceleration = Double.valueOf(s).doubleValue();
		}
		s = getParameter("dist");
		if ( s != null ){
			bestDistance = (new Integer(s)).intValue();
			//System.out.println(bestDistance);
		}
		s = getParameter("trail");
		if ( s != null ){
			trail = Boolean.valueOf(s).booleanValue();
		}
		s = getParameter("debag");
		if ( s != null ){
			debag = Boolean.valueOf(s).booleanValue();
		}
		s = getParameter("visibleAngle");
		if ( s != null ){
			visibleAngle = (double)((new Integer(s)).intValue())/2.0 * Math.PI/180.0;
		}
		ball = new Boid[max];
		LengthList = new int[ball.length][ball.length];
		angleList = new double[ball.length][ball.length];
		tempP_x = new double[ball.length];
		tempP_y = new double[ball.length];
		lastAngle = new double[ball.length];
		int px1,py1;
		double speedx,speedy,speed;
		for(int i = 0;i<ball.length;i++){
			px1 = (int)Math.round(Math.random()*(r.width/2)+0.5)+r.width/4;
			py1 = (int)Math.round(Math.random()*(r.height/2)+0.5)+r.height/4;
			speedx = Math.random()*2-1;
			speedy = Math.random()*2-1;
			speed = Math.random()*3+2.5;
			ball[i] = new Boid(width,height,px1,py1,speedx,speedy,speed);
		}
		offScreenImage = createImage(r.width, r.height);
		offScreenGraphics = offScreenImage.getGraphics();
		repaint();
	}
	
/**
*情報
*/
	public String getAppletInfo() {
		return "Boids-Modoki v0.1 (29 May 1996),by task gouda";
	}
	
/**
*パラメーターの説明
*/
  public String[][] getParameterInfo()  {
    String pinfo[][] = { 
      {"boids",    "int",    "Number of boids"}, 
      {"max",       "double",   "max speed"}, 
      {"dist",      "int",   "desired cruising distance"},
      {"copyWait",	"double",	"copyWait(0.0-1.0)"},
      {"centerWait",	"double",	"centerWait(0.0-1.0)"},
      {"acceleration",	"double",	"acceleration of speed(1.01-1.3)"},
      {"trail",	"boolean",	"clear screen or not clear"},
      {"debag",	"boolean",	"printout debag String for console"},
      {"visibleAngle",	"int",	"boid visible angle(1-360)"}
    }; 
    return pinfo;
  }

/**
* hypercard では resumeStack event 相当
*/
	public void start(){
		if( t == null ){
			t = new Thread(this);
			t.start();
		}
	}
	
/**
* hypercard では suspendStack event 相当
*/
	public void stop (){
		if( t != null ){
			t.stop();
			t=null;
		}
	}
	
/**
* hypercard では closeStack event 相当??
*/
	public void destroy (){
		this.stop();
	}
	
/**
*スレッドで実行
*/
	public void run(){
		while(t != null){
			culcNewSpeed();
			repaint();
			try{Thread.sleep(100);
			}
			catch(InterruptedException e){}
		}
	}
	public boolean mouseUp(Event evt,int x,int y){
		clear();
		reset();
		repaint();
		return true;
	}
	
	public void reset(){
		for(int i = 0;i<ball.length;i++){
			ball[i].x = (int)Math.round(Math.random()*(width/2)+0.5)+width/4;
			ball[i].y = (int)Math.round(Math.random()*(height/2)+0.5)+height/4;
			ball[i].vx = Math.random()*2-1;
			ball[i].vy = Math.random()*2-1;
			ball[i].speed = Math.random()*3+2.5;
			
		}
	}
	public void clear(){
		offScreenGraphics.setColor(new Color(0,0,0));
		offScreenGraphics.fillRect(0,0,width,height);
	}
/**
*ダブルバッファで画面描き換え
*/
	public final synchronized void update (Graphics g)
	{
		if( trail != true ){
			clear();
		}
		paint(offScreenGraphics);
		g.drawImage(offScreenImage, 0, 0, null);
	}
	
/**
*画面描画
*/
	public void paint(Graphics g){
		int px,py;
		if( debag == true ){
		System.out.println("-------");
		}
		colorA = ( colorA + 1 )% 256;
		colorB = ( colorB + 1 )% 256;
		for(int i = 0;i<ball.length;i++){
			// ----  moving Boids  ----
			ball[i].move();
			
			px = ball[i].x;
			py = ball[i].y;
			g.setColor(new Color((int)(colorA/2),colorB,255));
			g.fillOval(px-3,py-3,7,7);
			g.setColor(new Color(255,colorB,(int)(colorA/2)));
			g.drawLine(px,py,px+(int)(ball[i].vx*6.0),py+(int)(ball[i].vy*6.0));
			if ( debag == true){
			System.out.println("Boid" + i + " S=" + ball[i].speed +
								 " vx=" + ball[i].vx + " vy=" + ball[i].vy + 
								 " loc=" + ball[i].x + "," + ball[i].y);
			}
		}
	}

/**
*それぞれのあいだの距離の計算
*/
	private void culcDistance (){
		int k;
		for(int i = 0;i < ball.length;i++){
			for(int j = i;j < ball.length;j++){
				if ( i == j ){
					LengthList[i][j] = 0;
					angleList[i][j] = 0;
				}else{
					LengthList[i][j] = culcDistance( ball[i].x , ball[i].y , ball[j].x , ball[j].y );
					LengthList[j][i] = LengthList[i][j];
					if (LengthList[i][j] == 0){
						angleList[i][j] = 0 ; angleList[j][i] = 0;
					}else{
						angleList[i][j] = Math.acos( ( ball[j].x - ball[i].x ) / LengthList[i][j] );
						angleList[j][i] = Math.acos( ( ball[i].x - ball[j].x ) / LengthList[i][j] );
					}
				}
			}
		}
	}
/**
*距離の計算
*/
	private int culcDistance (int x1,int y1,int x2,int y2){
		return (int)Math.sqrt(Math.pow((x1-x2),2)+Math.pow((y1-y2),2));
	}
/**
*中心を求める
*/
	private Point getCenterPoint (){
		Point cp = new Point(0,0);
		for(int i = 0;i<ball.length;i++){
			cp.x += ball[i].x;
			cp.y += ball[i].y;
		}
		cp.x = cp.x/ball.length;
		cp.y = cp.y/ball.length;
		return cp;
	}
/**
*加重平均で中心点を求める
*/
	private Dpoint getCenterPoint (int a){
		Dpoint cp = new Dpoint(0,0);
		double base = 0,temp = 0;
		for(int i = 0;i<ball.length;i++){
			if ( i != a && LengthList[a][i] != 0 ){
				temp = (double)(1.0 + 10.0/(double)LengthList[a][i]);
				cp.x += (double) ball[i].x * temp;
				cp.y += (double) ball[i].y * temp;
				base += temp;
			}
		}
		cp.x = cp.x/base;
		cp.y = cp.y/base;
		return cp;
	}
/**
*ボイドの次のスピードと向きを計算する
*/
	private void culcNewSpeed(){
		int t,difx,dify;
		double x = 3,y = 3,dist,angle,angle2;
		Dpoint centerPoint;
		//centerPoint = getCenterPoint();
		culcDistance();
		
		for(int i = 0 ; i < ball.length ; i++){
		
			//向きの調節
			centerPoint = getCenterPoint(i);
			angle = getAngle( (centerPoint.x - ball[i].x) , (centerPoint.y - ball[i].y) );
			x = Math.cos(angle);
			y = Math.sin(angle);
			t = whoNear(i,lastAngle[i]);
			if ( t < 0 ){
				t = i;
			}
			x = ball[i].vx + ball[t].vx*copyWait + x*centerWait;
			y = ball[i].vy + ball[t].vy*copyWait + y*centerWait;
			if(x != 0 && y != 0){
				angle = getAngle(x,y);
				lastAngle[i] = angle;
				tempP_x[i] = (Math.cos(angle));
				tempP_y[i] = (Math.sin(angle));
			}else{
				lastAngle[i] = 0;
				tempP_x[i] = 0.0;
				tempP_y[i] = 0.0;
			}
			//スピードの調節
			difx = ball[t].x - ball[i].x;
			dify = ball[t].y - ball[i].y;
			dist = getDist(i,t);
			angle2 = getAngle(difx,dify);
			if (angle2 > angle){angle2 = angle2 - angle;}else{angle2 = angle - angle2;}
			if (dist > bestDistance + 0.5) {
				if(angle2 < ( Math.PI/2) || angle2 > (Math.PI * 1.5)){
					ball[i].speed *= acceleration;
				}else{
					ball[i].speed /= acceleration;
				}
			}else if (dist < bestDistance - 0.5) {
				if(angle2 < (Math.PI/2) || angle2 > (Math.PI * 1.5)){
					ball[i].speed /= acceleration;
				}else{
					ball[i].speed *= acceleration;
				}
			}
			if(ball[i].speed > maxSpeed){
				ball[i].speed = maxSpeed;
			}else if (ball[i].speed <= 4){
				ball[i].speed = 4;
			}
		}
		for(int i = 0 ; i < ball.length ; i++){
			ball[i].vx = tempP_x[i];
			ball[i].vy = tempP_y[i];
		}
		
	}
/**
*角度を計算
*@param		double x
*@param		double y
*@return	finded index number
*/
	private double getAngle (double x,double y){
		double dist;
		if (y == 0  && x == 0){
			return 0;
		}
		/*if (x == 0 && y > 0){
			return Math.PI*0.5;
		}else if (x == 0 && y < 0){
			return Math.PI*1.5;
		}*/
		dist = Math.sqrt(Math.pow(x,2) + Math.pow(y,2));
		if (y > 0){
			return (Math.acos(x/dist));
		}else{
			return (Math.PI*2-Math.acos(x/dist));
		}
	}
/**
*一番近くのボイドをさがす
*@param		index number of me
*@return	finded index number
*/
	private int whoNear( int n , double angle){
		int dist,x = -1;
		double kx;
		dist = Integer.MAX_VALUE;
		for(int i = 0;i < ball.length;i++){
			if ( angle > angleList[n][i]){
				kx = angle - angleList[n][i];
			}else{
				kx = angleList[n][i] - angle;
			}
			if ( n != i && 
				LengthList[n][i] < dist &&
				( kx < visibleAngle || 
				kx > (2 * Math.PI - visibleAngle)))
			{
				dist = LengthList[n][i];
				x = i;
			}
		}
		return x;
	}
/**
*ボイド間の距離を返す
*/
	private int getDist(int a,int b){
		return LengthList[a][b];
	}
}

/**
*ボイド
*/
class Boid{
	int width = 0,height = 0,x = 0,y = 0;
	double vx,vy,speed = 5;
	Boid(int width,int height,int locX,int locY,double speedX,double speedY,double speed){
		this.width = width;
		this.height = height;
		this.speed = speed;
		x = locX;
		y = locY;
		vx = speedX;
		vy = speedY;
	}
/**
*移動
*/
	public void move(){
		x += (int)(vx*speed);
		y += (int)(vy*speed);
		if(x >= width ){
			x -= width;
		}else if( x <= 0){
			x += width;
		}
		if(y >= height){
			y -= height;
		}else if( y <= 0){
			y += height;
		}
	}
}

/**
*doubleのPoint
*/
class Dpoint{
	double x,y;
	Dpoint (double x,double y){
		this.x = x;
		this.y = y;
	}
}