オブジェクトをマウスの方向に、回転行列(Rotating Matrix)を使って回転させる|HTML5

オブジェクトをマウスの方向に、回転行列(Rotating Matrix)を使って回転させる|HTML5

回転行列の公式(x’ = cosθ * x – sinθ * y, y’ = sinθ * x + cosθ * y)を使って、Canvasに描いたオブジェクトをマウスの方向に回転させる。

オブジェクトをマウスの方向に、回転行列(Rotating Matrix)を使って回転させる(HTML5, JavaScript, CSS3) : デモ

オブジェクトをマウスの方向に、回転行列(Rotating Matrix)を使って回転させる(HTML5, JavaScript, CSS3) : ZIPファイル(6kb)

1.HTML

<!DOCTYPE html>
<html lang="jp">
	<head>
		<meta charset="UTF-8" />
		<title>マウスの方向に回転行列|Rotate Matrix to Mouse</title>
		<link href="css/base.css" rel="stylesheet" type="text/css">
		<script src="js/base.js"></script>
		<script src="js/devicecheck.js"></script>
	</head>
	<body>
		<div id="contents">
			<canvas id="canvas" width="300" height="300">
			</canvas>
		</div>
	</body>
</html>

2.CSS

@charset "utf-8";

body
{
	margin:0;
	padding:0;
	background-color: #fff;
	font-family:Helvetica, HiraKakuProN-W3, sans-serif; 
	font-size:12px;
	color:#000;
}

#contents
{
	position: absolute;
	top: 0;
	left: 0;
	width: 300px;
	height:300px;
	border: 1px solid #000;
	overflow:hidden;
}

#canvas
{
	position: absolute;
	top: 0;
	left: 0;
	width: 300px;
	height:300px;
}

3.JavaScript

devicecheck.js

var g_mobiledevice = false;	//iPhone、iPad、Androidのときtrue
var g_browsername = 'unknown';
var g_browserver = -1;

if(checkUserAgent() == false)
{
	window.alert('このブラウザは対象外です');
}

function checkUserAgent()
{
	var ua = navigator.userAgent;

	//iPhoneか?	
	var mstr = ua.match(/iPhone OS \d+/);
	if(mstr != null){
		var vstr = mstr[0].match(/\d+/);
		if(parseInt(vstr[0]) >= 3) 
		{
			g_mobiledevice = true;
			g_browsername = 'iPhone';
			//alert('major-version ' + vstr);
			return true;
		}
	}
	//iPadか?
	if(ua.indexOf('iPad') > -1)
	{
		mstr = ua.match(/CPU OS \d+/);
		if(mstr != null)
		{
			var vstr = mstr[0].match(/\d+/);
			if(parseInt(vstr[0]) >= 3) {
				g_mobiledevice = true;
				g_browsername = 'iPad';
				//alert('major-version ' + vstr);
				return true;
			}		
		}		
	}	
	//Androidか?	
	var mstr = ua.match(/Android \d+\.\d+/);
	if(mstr != null)
	{
		g_browsername = 'Android';
		var vstr = mstr[0].match(/\d+\.\d+/);
		g_browserver = parseFloat(vstr[0]);
		g_mobiledevice = true;
		if(pg_browserver > 2.1) 
		{
			//alert('version ' + vstr);
			return true;
		}
	}
	//Chromeか?
	mstr = ua.match(/Chrome\/\d+/);
	if(mstr != null)
	{
		g_browsername = 'Chrome';
		var vstr = mstr[0].match(/\d+/);
		g_browserver = parseInt(vstr[0]);
		if(g_browserver >= 9) 
		{
			//alert('major-version ' + vstr);
			
			return true;
		}		
	}
	//Safariか?
	if(ua.indexOf('Safari') > -1)
	{
		mstr = ua.match(/Version\/\d+/);
		if(mstr != null){
			var vstr = mstr[0].match(/\d+/);
			if(parseInt(vstr[0]) >= 5) 
			{
				g_browsername = 'Safari';
				//alert('major-version ' + vstr);
				return true;
			}		
		}		
	}
	//Internet Explorerか?
	mstr = ua.match(/MSIE \d+/);
	if(mstr != null)
	{
		var vstr = mstr[0].match(/\d+/);
		if(parseInt(vstr[0]) >= 9) 
		{
			g_browsername = 'MSIE';
			//alert('major-version ' + vstr);
			return true;
		}		
	}
	//Firefoxか?
	mstr = ua.match(/Firefox\/\d+/);
	if(mstr != null){
		var vstr = mstr[0].match(/\d+/);
		if(parseInt(vstr[0]) >= 4) 
		{
			g_browsername = 'Firefox';
			//alert('major-version ' + vstr);
			return true;
		}		
	}
	//Operaか?
	if(ua.indexOf('Opera') > -1)
	{
		mstr = ua.match(/Version\/\d+/);
		if(mstr != null){
			var vstr = mstr[0].match(/\d+/);
			if(parseInt(vstr[0]) >= 11) 
			{
				g_browsername = 'Opera';
				//alert('major-version ' + vstr);
				return true;
			}		
		}		
	}
	
	return false;
}

base.js

window.addEventListener("load", init, false);

var centerX;
var centerY;
var theCanvas;
var ctx;
var currentX0;
var currentY0;
var currentX1;
var currentY1;
var currentX2;
var currentY2;
var points = new Array();
var mouseX;
var mouseY;

function init()
{
	document.getElementById('canvas').addEventListener('touchstart', function() 
	{
		event.preventDefault();
	});
	document.getElementById('canvas').addEventListener('touchmove', function() 
	{
		event.preventDefault();
	});
	document.getElementById('canvas').addEventListener('touchend', function() 
	{
		event.preventDefault();
	});
	//ボタンタイプ
	if(g_mobiledevice==true)
	{
		buttonStart = 'touchstart';
		buttonMove = 'touchmove';
		buttonEnd = 'touchend';
	}
	else
	{
		buttonStart = 'mousedown';
		buttonMove = 'mousemove';
		buttonEnd = 'mouseup';
	}
	
	theCanvas = document.getElementById("contents");
	centerX = (theCanvas.currentStyle || document.defaultView.getComputedStyle(theCanvas,'')).width;
	centerX = Number(centerX.replace('px',''));
	centerX =  centerX / 2;
	centerY = (theCanvas.currentStyle || document.defaultView.getComputedStyle(theCanvas,'')).height;
	centerY = Number(centerY.replace('px',''));
	centerY =  centerY / 2;
	
	theCanvas = document.getElementById("canvas");
	
	theCanvas.addEventListener(buttonMove, mouseDownHandler, false);
	
	function mouseDownHandler(e) 
	{
		if(g_mobiledevice)
		{
		        var rect = event.currentTarget.getBoundingClientRect();	
			mouseX = event.touches[0].pageX - rect.left - centerX;
			mouseY = event.touches[0].pageY - rect.top - centerY;
		}
                else
		if(g_browsername == 'MSIE' || g_browsername == 'Opera')
		{
			rect = document.getElementById("canvas").getBoundingClientRect();
			mouseX = event.clientX - rect.left - centerX;
			mouseY = event.clientY - rect.top - centerY;
		}
		else
		if(g_browsername == 'Firefox')
		{
			rect = document.getElementById("canvas").getBoundingClientRect();
			mouseX = e.clientX - rect.left - centerX;
			mouseY = e.clientY - rect.top - centerY;
		}
		else
		{
                        rect = event.currentTarget.getBoundingClientRect();
			mouseX =  event.clientX - rect.left - centerX;
			mouseY =  event.clientY - rect.top - centerY;
		}
		
		set(mouseX, mouseY);
	}
	ctx =  theCanvas.getContext("2d");
	
	var x = Math.cos(18*Math.PI/180)*50*1.62;
	var y = Math.sin(18*Math.PI/180)*50*1.62;

	points.push({x:-(x/2),y:-y});
	points.push({x:x/2,y:0});
	points.push({x:-(x/2),y:y});
	
	set(0,0);
}

function set(mx,my)
{
	var mx = mx;
	var my = my;
	ctx.clearRect(0,0,300,300);	
	var dx = mx;
	var dy = my;
	var radian = Math.atan2(dy,dx);
	
	var i=0;
	var currentX0 = Math.cos(radian)*points[i].x-Math.sin(radian)*points[i].y;
	var currentY0 = Math.sin(radian)*points[i].x+Math.cos(radian)*points[i].y;
	
	i=1;
	var currentX1 = Math.cos(radian)*points[i].x-Math.sin(radian)*points[i].y;
	var currentY1 = Math.sin(radian)*points[i].x+Math.cos(radian)*points[i].y;
	
	i=2;
	var currentX2 = Math.cos(radian)*points[i].x-Math.sin(radian)*points[i].y;
	var currentY2 = Math.sin(radian)*points[i].x+Math.cos(radian)*points[i].y;
	
	draw(currentX0,currentY0,currentX1,currentY1,currentX2,currentY2);
}

function draw(currentX0,currentY0,currentX1,currentY1,currentX2,currentY2)
{
	ctx.strokeStyle="#000000";
	ctx.lineWidth=1;
	ctx.beginPath();
	ctx.moveTo(centerX+currentX0, centerY+currentY0);
	ctx.lineTo(centerX+currentX1, centerY+currentY1);
	ctx.lineTo(centerX+currentX2, centerY+currentY2);
	ctx.lineTo(centerX+currentX0, centerY+currentY0);
	ctx.stroke();
}

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