1 files changed, 114 insertions, 0 deletions
diff --git a/sensfreq/main.js b/sensfreq/main.js
new file mode 100644
index 0000000..6dc431e
--- /dev/null
+++ b/sensfreq/main.js
@@ -0,0 +1,114 @@
+const audioCtx = new (window.AudioContext || window.webkitAudioContext)();
+
+e = s => document.getElementById(s);
+
+let ans = false;
+let nq = 0;
+let nc = 0;
+
+function init()
+{
+	e("gench").disabled = false;
+	e("response").style.display="none";
+	reset_stats();
+	loadTheme();
+}
+
+function play_notes(freq, t, arpt)
+{
+	const stop_notes=function(g, o)
+	{
+		o.stop();
+		g.disconnect(audioCtx.destination);
+		o.disconnect(g);
+	}
+	const play_note=function(f)
+	{
+		const gn = audioCtx.createGain();
+		gn.gain.setValueAtTime(.5/freq.length, audioCtx.currentTime);
+		gn.gain.linearRampToValueAtTime(0, audioCtx.currentTime + t / 1000.);
+		gn.connect(audioCtx.destination);
+		const osc = audioCtx.createOscillator();
+		osc.type = "sine";
+		osc.frequency.setValueAtTime(f, audioCtx.currentTime);
+		osc.connect(gn);
+		osc.start();
+		setTimeout(stop_notes.bind(null, gn, osc), t);
+	}
+	let i=0;
+	freq.forEach(function(f){setTimeout(play_note.bind(null, f), arpt * (i++));});
+}
+
+get_freq = n => 440 * Math.pow(Math.pow(2, 1./12), n-69)
+
+function generate_challenge()
+{
+	const nmin=Number(e("minnnotes").value);
+	const nmax=Number(e("maxnnotes").value);
+	const omin=Number(e("minorange").value);
+	const omax=Number(e("maxorange").value);
+	if (omax < omin || nmax < nmin)
+	{
+		alert("?");
+		return;
+	}
+	const nnotes = Math.floor(Math.random() * (nmax - nmin + 1)) + nmin;
+	const minrange = 60 + omin * 12;
+	const maxrange = 71 + omax * 12;
+	
+	let f = [];
+	let l = [];
+	ans = false;
+	
+	if (Math.random() < 0.3)
+	{
+		const o = Math.floor(Math.random() * (omax - omin + 1)) + omin;
+		let n = 60 + Number(e("note").value) + o * 12;
+		f.push(get_freq(n));
+		l.push(n);
+		ans = true;
+	}
+	while (f.length < nnotes)
+	{
+		let n = Math.floor(Math.random() * (maxrange - minrange + 1)) + minrange;
+		if (l.indexOf(n)!=-1)
+			continue;
+		ans |= ((n % 12) == Number(e("note").value));
+		f.push(get_freq(n));
+	}
+	f.sort((a,b)=>a-b);
+	play_notes(f, 1000, e("arp").checked ? 50 : 0);
+	e("gench").disabled = true;
+	e("response").style.display="";
+}
+
+function update_stats()
+{
+	e("stats").innerHTML=`You got ${nc} of the ${nq} challenges correct.`
+}
+
+function reset_stats()
+{
+	nq = nc = 0;
+	update_stats();
+}
+
+function check_yes()
+{
+	if (ans)
+		++nc;
+	++nq;
+	e("gench").disabled = false;
+	e("response").style.display="none";
+	update_stats();
+}
+
+function check_no()
+{
+	if (!ans)
+		++nc;
+	++nq;
+	e("gench").disabled = false;
+	e("response").style.display="none";
+	update_stats();
+}