<html> <head> <script type="text/javascript" src="https://www.google.com/jsapi"></script> <script type="text/javascript"> google.load("visualization", "1", {packages:["corechart"]}); google.setOnLoadCallback(drawChart); function drawChart() { var options = { title: 'Wave form qr=60' }; var chart = new google.visualization.LineChart(document.getElementById('chart_div')); //chart.draw(data, options); function redraw() { var params = []; for (var i = 0; i < 8; i++) { params.push(parseInt(document.getElementById("param" + i).value)); } var nsamp = parseInt(document.getElementById("nsamp").value); var rawdata = envdata(params, nsamp); var data = google.visualization.arrayToDataTable(rawdata); chart.draw(data, {title: 'Envelope'}); } for (var i = 0; i < 8; i++) { document.getElementById("param" + i).addEventListener("change", redraw); } document.getElementById("nsamp").addEventListener("change", redraw); redraw(); } </script> </head> <body> Level 1: <input id="param0" type="text" value="99"> Rate 1: <input id="param4" type="text" value="80"><br/> Level 2: <input id="param1" type="text" value="80"> Rate 2: <input id="param5" type="text" value="80"><br/> Level 3: <input id="param2" type="text" value="99"> Rate 3: <input id="param6" type="text" value="70"><br/> Level 4: <input id="param3" type="text" value="0"> Rate 4: <input id="param7" type="text" value="80"><br/> Number of samples: <input id="nsamp" type="text" value="4000"><br/> <div id="chart_div" style="width: 900px; height: 500px;"></div> </body> <script> var envmask = [[0, 1, 0, 1, 0, 1, 0, 1], [0, 1, 0, 1, 0, 1, 1, 1], [0, 1, 1, 1, 0, 1, 1, 1], [0, 1, 1, 1, 1, 1, 1, 1]]; var outputlevel = [0, 5, 9, 13, 17, 20, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 42, 43, 45, 46, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127]; function envenable(i, qr) { var shift = (qr >> 2) - 11; if (shift < 0) { var sm = (1 << -shift) - 1; if ((i & sm) != sm) return false; i >>= -shift; } return envmask[qr & 3][i & 7] != 0; } function attackstep(lev, i, qr) { var shift = (qr >> 2) - 11; if (!envenable(i, qr)) return lev; var slope = 17 - (lev >> 8); lev += slope << Math.max(shift, 0); return lev; } function decaystep(lev, i, qr) { var shift = (qr >> 2) - 11; if (!envenable(i, qr)) return lev; lev -= 1 << Math.max(shift, 0); return lev; } function Env(params) { this.params = params; this.level = 0; this.ix = 0; this.i = 0; this.down = true; this.advance(0); } Env.prototype.getsample = function() { if (envenable(this.i, this.qr) && (this.ix < 3 || (this.ix < 4 && !this.down))) { if (this.rising) { var lev = attackstep(this.level, this.i, this.qr); console.log(lev); if (lev >= this.targetlevel) { lev = this.targetlevel; this.advance(this.ix + 1); } this.level = lev; } else { var lev = decaystep(this.level, this.i, this.qr); if (lev <= this.targetlevel) { lev = this.targetlevel; this.advance(this.ix + 1); } this.level = lev; } } this.i++; return this.level; } Env.prototype.advance = function(newix) { this.ix = newix; if (this.ix < 4) { var newlevel = this.params[this.ix]; var scaledlevel = Math.max(0, (outputlevel[newlevel] << 5) - 224); this.targetlevel = scaledlevel; this.rising = (this.targetlevel - this.level) > 0; var rate_scaling = 0; this.qr = Math.min(63, rate_scaling + ((this.params[this.ix + 4] * 41) >> 6)); } //console.log("advance ix="+this.ix+", qr="+this.qr+", target="+this.targetlevel+", rising="+this.rising); } Env.prototype.keyup = function() { this.down = false; this.advance(3); } function attackdata(qr) { var result = [['samp', 'env']]; var i = 0; var count = 0; var lev = 1716; while (true) { result.push([i, lev]); lev = attackstep(lev, i, qr); lev = Math.min(lev, 15 << 8); if (lev >= 15 << 8) { count++; if (count > 100) break; } i++; } return result; } function envdata(params, nsamp) { console.log(nsamp); var result = [['samp', 'env']]; var env = new Env(params); for (var i = 0; i < nsamp; i++) { if (i == 3 * nsamp / 4) { env.keyup(); } result.push([i, env.getsample()]); } return result; } </script> </html>