PM-visualization/gif.html at master · khoin/PM-visualization · GitHub

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<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<title>Visualizing Phase Modulation</title>
	<link href="https://fonts.googleapis.com/css?family=Cormorant+Infant" rel="stylesheet">
	<script src="gif.js"></script>
	<style>
		html {padding:0; margin: 0;
			background: repeating-radial-gradient(rgba(0,0,0,0.4) 0%,#eee 1px,#eee);
			background-size: 13px 13px;
		}
		body {
			font-family: 'Cormorant Infant', serif;
			color: #66656B;
			margin: 0 auto;
			padding: 35px;
			max-width: 600px;
			background: #f9f7f5;
			box-shadow:  rgba(0,0,0,0.3) 0 0 25px 0;
		}
		canvas {
			width:100%;
			height:100%;
		}
		.half {
			width:50%;
		}
		h1 {
			font-size: 250%;
			text-align: center;
		}
		#notation {
			font-size: 40px;
			text-align: left;
		}
		#notation>input { font-weight: bold; }
		input {
			line-height: 1em; height: 1em; display: inline-block; background: #f9f7f5; border: none;
			width: 1em; font-size: 40px; font-family: 'Cormorant Infant', serif;
		}
		.r1 { color: #C65D1F; }
		.r2, .r3 { color: #1F66C4; }
		#r2, #r3 { width: 1.5em; }
		#f, #a 	{ width: 2.7em; text-align: right;}
		#ft { color: #65907d; font-weight: bold;}
	</style>
</head>
<body>
<h1><em>Phase Modulation</em></h1>
<canvas id="c" class=""></canvas>
<div id="notation">
	<button onclick="dr();"> next frame</button>
	<button onclick="aframe();"> add frame</button>
	<button onclick="gif.render();"> render</button>
	<button onclick="cycle();"> CYCLE </button>
	<button onclick="cycle(123);"> CYCLE ADD</button>
</div>
<script>var d = document;
//CONSTANTS BUT THEY'RE VAR
var r1 = 3,
	r2 = 2,
	r3 = 0.5,
	f = 40,
	a = 0;
/**
d.getElementById("r1").addEventListener("change", function(e) {
	r1 = e.target.value;
});
d.getElementById("r2").addEventListener("change", function(e) {
	r2 = e.target.value;
});
d.getElementById("r3").addEventListener("change", function(e) {
	r3 = e.target.value;
});
d.getElementById("f").addEventListener("change", function(e) {
	f = e.target.value;
});
d.getElementById("a").addEventListener("change", function(e) {
	a = e.target.value;
});
**/
// audio stuff
var aC = new AudioContext();
var node = aC.createScriptProcessor(4096, 0, 1);

var t = 0;

var dsp = function(t) {
	return Math.sin(r1*Math.PI*2*t*f + r3*Math.PI*Math.sin(r2*Math.PI*2*t*f) )* a;
}

node.connect(aC.destination);
node.onaudioprocess = function(audioProcessingEvent) {
	var obuffer = audioProcessingEvent.outputBuffer;
	for( var ch=0; ch < obuffer.numberOfChannels; ch++ ){
		var odata = obuffer.getChannelData(ch);
		for(var i=0; i<obuffer.length; i++) {
			odata[i] = dsp(t + (i/aC.sampleRate) );
		}
	}
	t += obuffer.length/aC.sampleRate;
}

// visual stuff
	var
		c = d.getElementById("c"),
		l = c.getBoundingClientRect(),
		ctx = c.getContext("2d"),
		w = l.width;

		c.width = w; c.height = w ;

		ctx.lineWidth = 3;

		function drawBg() {
			ctx.fillStyle = "#fff";
			ctx.fillRect(0,0, w, w);
		}

		function drawBox(x, y, w, h, c) {
			ctx.strokeStyle = c || "#77756B";
			ctx.strokeRect(x, y, w, h)
		}

		function drawLine(x,y, m,n) {
			ctx.beginPath();
			ctx.moveTo(x,y);
			ctx.lineTo(m,n);
			ctx.stroke();
		}

		function drawWave(x,y, w,h, f, k) {
			if(!k) {
				ctx.beginPath();
				moveTo( x + (w/2) + w*f(0) ,y);
				for(var i = 0; i<h; i++) {
					ctx.lineTo( x + (w/2) + (w/2)*f(i) , y+i);
				}
				ctx.stroke();
			} else {
				ctx.beginPath();
				moveTo( x, y + (h/2) + h*f(0) );
				for(var i = 0; i<w; i++) {
					ctx.lineTo( x+i, y + (h/2) + (h/2)*f(i));
				}
				ctx.stroke();
			}
		}

		var Wave = (function(f){
			this.valueAt = function(z) {
				return f(z);
			}
			return this;
		});

		var Buffe = (function(size) {
			var buff = [];

			for(var j=0; j<size; j++, buff[j]=0);

			this.addValue = function(v) {
				if(buff.length > size) buff.shift();
				buff.push(v);
			}
			this.valueAt = function(i) {
				return (buff[size-i])? buff[size-i]:0;
			}

			return this;
		});
var _t = 0;
var zf = [];

var gif = new GIF({
	workers: 5,
	quality: 40,
	repeat: 0,
	width: 600,
	height: 600
});


function aframe() {
	gif.addFrame(ctx, { copy: true, delay: 60}); dr();
}


		//carrier
		var carrier = new Wave(function(z) {
			return Math.sin( (-_t/1000)*r1 + 4*Math.PI*(z/(w/2)) );
		});
		//mod
		var modu 	= new Wave(function(z) {
			return Math.sin( ( _t/1000)*r2 + 4*Math.PI*(z/(w/2)));
		});
		//out
		var output 	= new Buffe(~~w/2);

		function dr() {
			drawBg();
			_t += 1000*Math.PI/72;

			//carrier txt
			ctx.font = "bold 22px monospace";
			ctx.fillStyle="#C65D1F";
			ctx.fillText("f₁ = "+r1, w/8	, w/8 -10);
			//mod txt
			ctx.font = "bold 22px monospace";
			ctx.fillStyle="#1F66C4";
			ctx.fillText("f₂ = "+r2, w*3/8	, w/8+ w*(2-r3)/8 -10);
			//equation txt
			ctx.font = "bold 22px monospace";
			ctx.fillStyle="#C65D1F";
			ctx.fillText("sin(f₁t               )", w*3/8	, w*6/8 - 10);
			ctx.fillStyle="#1F66C4";
			ctx.fillText("        + π/2 sin(f₂t) ", w*3/8	, w*6/8 - 10);

			ctx.strokeStyle = "#77756B";

			//carrier
			drawBox(w/8		, w/8				, w/8	, w/2	, "#C65D1F");
			//modulator
			drawBox(w*3/8	, w/8+ w*(2-r3)/8	, w/2	, w*r3/4, "#1F66C4");
			//out
			drawBox(w*3/8	, w*6/8				, w/2	, w/8	, "#65907d");
			//reflector
			drawLine(w/8	, w*6/8				, w/4	, w*7/8);

			//carrier
			ctx.strokeStyle = "#C65D1F";
			drawWave(w/8, w/8, w/8, w/2, function(z) {
				return carrier.valueAt(z);
			});

			//mod
			ctx.strokeStyle = "#1F66C4";
			drawWave(w*3/8, w/8+ w*(2-r3)/8, w/2, w*r3/4, function(z) {
				return modu.valueAt(z);
			}, 1);

			//out
			ctx.strokeStyle = "#65907d";
			output.addValue(carrier.valueAt(w/4+w*r3/8*modu.valueAt(0)));
			if( Math.round( carrier.valueAt(w/4+w*r3/8*modu.valueAt(0))*100 ) == 0 ) console.log("zero!"), zf.push(_t/30) ;
			drawWave(w*3/8, w*6/8, w/2, w/8, function(z) {
				return output.valueAt(z);
				//return carrier.valueAt(w/4+z+w/16*modu.valueAt(0))
			}, 1);

			//mod to carrier
			ctx.strokeStyle = "#1F66C4";
			drawLine(	w*3/8,
						w*2.5/8 + w/16 	+ w*r3/8*modu.valueAt(0),
						w/8		+ w/16	+ w/16*carrier.valueAt(w/4+w*r3/8*modu.valueAt(0)),
						w*2.5/8 + w/16 	+ w*r3/8*modu.valueAt(0) );

			//carrier to reflector
			ctx.strokeStyle = "#C65D1F";
			drawLine(	w/8		+ w/16	+ w/16*carrier.valueAt(w/4+w*r3/8*modu.valueAt(0)),
						w*2.5/8 + w/16 	+ w*r3/8*modu.valueAt(0),
						w/8		+ w/16	+ w/16*carrier.valueAt(w/4+w*r3/8*modu.valueAt(0)),
						w*6/8 	+ w/16 	+ w/16*carrier.valueAt(w/4+w*r3/8*modu.valueAt(0))
						);

			ctx.strokeStyle = "#65907d";
			//reflector to output
			drawLine(	w/8		+ w/16	+ w/16*carrier.valueAt(w/4+w*r3/8*modu.valueAt(0)),
						w*6/8 	+ w/16 	+ w/16*carrier.valueAt(w/4+w*r3/8*modu.valueAt(0)),
						w*3/8,
						w*6/8 	+ w/16 	+ w/16*carrier.valueAt(w/4+w*r3/8*modu.valueAt(0)));
			//requestAnimationFrame(dr);
		};

gif.on('finished', function(blob) {
  window.open(URL.createObjectURL(blob));
});

function cycle(a) {
	for(var i=0; i < 72*2; i++ ) {
		if (!a || i%2 !== 0) { dr(); }
		else { aframe(); }
	}
}
</script>
</body>
</html>