nyango/README

## README
なんかストレンジアトラクタとか欲しかったし練習で書いてみた。


クリックすると再描画しますー

ーー
js覚えたてのとき書いたもの
http://jsdo.it/jag/gMbb/

## jsdoit.css
body { background-color: #DDDDDD; font: 30px sans-serif; }

## jsdoit.html
<body onload="draw();" onclick="draw();">
        <canvas id="tutorial" width="600" height="600"></canvas>
    </body>

## jsdoit.js
          function draw(){
                var canvas = document.getElementById('tutorial');
                if (canvas.getContext){
                    var ctx = canvas.getContext('2d');
               		ctx.clearRect(0,0,9999,9999);
                    ctx.globalAlpha = 0.3;
                    NUM = 10000;
                    bairitu = 20;
                    WIDTH = canvas.width;
                    arraymaker();
                    maxBound = 500;
                    minBound = 500;

                    var g = b = 0;
                    var drawX,drawY;
                    for(i = 1; i < NUM; i++){
                        ctx.beginPath();
                        var markColor = 128*Math.floor(2 * i/NUM);
                        r = markColor;
                        ctx.strokeStyle = 'rgb(' + r + ',' + g + ',' + b + ')';
                                tmpDraw = miliDraw(seqX[i-1],seqY[i-1],seqZ[i-1]);
                                ctx.moveTo(tmpDraw[0],tmpDraw[1]);
                                tmpDraw = miliDraw(seqX[i],seqY[i],seqZ[i]);
                                ctx.lineTo(tmpDraw[0],tmpDraw[1]);
                                ctx.stroke();
                    }
                 }
              }


                function miliDraw(x,y,z){
                    X1 = -(x - y)*0.7;
                    Y1 = (x + y)*0.408 + z*0.81;
                    Y1 *= -1;
                    X1 *= bairitu;
                    Y1 *= bairitu;
                    X1 += WIDTH/2;
                    Y1 += WIDTH/2;
                    return [X1,Y1];
                }

                function boundCheck(tmp){
                        if (tmp > maxBound){
                            tmp = maxBound;
                        }
                        if (tmp < minBound){
                            tmp = minBound;
                       }
                        return tmp;
                }
                function arraymaker(){
                    seqX = new Array(NUM);
                    seqY = new Array(NUM);
                    seqZ = new Array(NUM);
                    seqX[0] = Math.random();
                    seqY[0] = 0;
                    seqZ[0] = 0;
                    a = b = 0.2;
                    c = 10*Math.random();
                    maxBound = 500;
                    minBound = -500;
                    dt = 0.01;
                    for(i = 1; i < NUM; i++){
                        tmpX = boundCheck(seqX[i-1]);
                        tmpY = boundCheck(seqY[i-1]);
                        tmpZ = boundCheck(seqZ[i-1]);
                        seqX[i] = tmpX + dt*(- tmpY - tmpZ);
                        seqY[i] = tmpY + dt*(a*tmpY + tmpX);
                        seqZ[i] = tmpZ + dt*(tmpZ*(tmpX - c) + b);
                   }
                }
	なんかストレンジアトラクタとか欲しかったし練習で書いてみた。


	クリックすると再描画しますー

	ーー
	js覚えたてのとき書いたもの
	http://jsdo.it/jag/gMbb/
	<body onload="draw();" onclick="draw();">
	<canvas id="tutorial" width="600" height="600"></canvas>
	</body>
	function draw(){
	var canvas = document.getElementById('tutorial');
	if (canvas.getContext){
	var ctx = canvas.getContext('2d');
	ctx.clearRect(0,0,9999,9999);
	ctx.globalAlpha = 0.3;
	NUM = 10000;
	bairitu = 20;
	WIDTH = canvas.width;
	arraymaker();
	maxBound = 500;
	minBound = 500;

	var g = b = 0;
	var drawX,drawY;
	for(i = 1; i < NUM; i++){
	ctx.beginPath();
	var markColor = 128Math.floor(2 i/NUM);
	r = markColor;
	ctx.strokeStyle = 'rgb(' + r + ',' + g + ',' + b + ')';
	tmpDraw = miliDraw(seqX[i-1],seqY[i-1],seqZ[i-1]);
	ctx.moveTo(tmpDraw[0],tmpDraw[1]);
	tmpDraw = miliDraw(seqX[i],seqY[i],seqZ[i]);
	ctx.lineTo(tmpDraw[0],tmpDraw[1]);
	ctx.stroke();
	}
	}
	}


	function miliDraw(x,y,z){
	X1 = -(x - y)*0.7;
	Y1 = (x + y)0.408 + z0.81;
	Y1 *= -1;
	X1 *= bairitu;
	Y1 *= bairitu;
	X1 += WIDTH/2;
	Y1 += WIDTH/2;
	return [X1,Y1];
	}

	function boundCheck(tmp){
	if (tmp > maxBound){
	tmp = maxBound;
	}
	if (tmp < minBound){
	tmp = minBound;
	}
	return tmp;
	}
	function arraymaker(){
	seqX = new Array(NUM);
	seqY = new Array(NUM);
	seqZ = new Array(NUM);
	seqX[0] = Math.random();
	seqY[0] = 0;
	seqZ[0] = 0;
	a = b = 0.2;
	c = 10*Math.random();
	maxBound = 500;
	minBound = -500;
	dt = 0.01;
	for(i = 1; i < NUM; i++){
	tmpX = boundCheck(seqX[i-1]);
	tmpY = boundCheck(seqY[i-1]);
	tmpZ = boundCheck(seqZ[i-1]);
	seqX[i] = tmpX + dt*(- tmpY - tmpZ);
	seqY[i] = tmpY + dt(atmpY + tmpX);
	seqZ[i] = tmpZ + dt(tmpZ(tmpX - c) + b);
	}
	}