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spline.html
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spline.html
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<!DOCTYPE html>
<html>
<head>
<script src="js/nexusUI.js"></script>
</head>
<style type="text/css">
body{
font-style:Helvetica;
}
#background{
background-color: #bbccFF;
opacity:0.1;
position:fixed;
margin:-10px;
width:100%;
height:100%;
}
#canvas{
position:relative;
width:800px;
height:300px;
top:50px;
margin: 30px auto;
display:block;
box-shadow:1px 1px #e0e0e0;
background-color: #fff;
}
#top{
background-color: #fafafa;
padding:20px;
margin:-10px;
box-shadow:1px 1px #e0e0e0;
z-index:10;
}
#top p{
position:relative;
left:22%;
color:#0000a0;
font-size:15pt;
font-family:Helvetica;
display:block;
margin: 10px auto;
}
.widg{
width:50px;
height:50px;
position:relative;
display:inline;
left:100px;
z-index:20;
margin-left:-50px;
}
.contain{
position:relative;
display:inline;
font-family:Helvetica;
font-size:10pt;
background-color: #fafafa;
}
.contain p{
position:relative;
display:inline;
top:20px;
left:20px;
padding-left:10px;
}
#control{
position:relative;
top:100px;
width:560px;
height:60px;
margin: auto;
display:block;
margin-top: -30px;
padding:40px 20px;
box-shadow:0px 1px 1px 0px #e0e0e0;
background-color: #fff;
}
#number{
width:100px;
}
footer{
position:fixed;
margin:-8px;
bottom:0px;
height:40px;
width:100%;
background-color: #fafafa;
padding:30px;
font-size:12pt;
}
footer p{
left:100px;
}
#fork{
position:relative;
width:50px;
height:50px;
display:inline;
left:80%;
top:-60px;
}
a{
color:#000;
}
</style>
<body>
<div id="background"></div>
<div id="top">
<p>GendyJS</p>
<p>A Web Audio Dynamic Stochastic Synthesis Algorithm</p>
</div>
<canvas id="canvas"></canvas>
<div id="control">
<canvas nx="toggle"></canvas>
<div class="contain">
<canvas nx="number" class="widg"></canvas>
<p># breakpoints</p>
</div>
<div class="contain">
<canvas nx="dial" class="widg"></canvas>
<p>x step size</p>
</div>
<div class="contain">
<canvas nx="dial" class="widg"></canvas>
<p>y bounds</p>
</div>
<div class="contain">
<canvas nx="dial" class="widg"></canvas>
<p>y step size</p>
</div>
<div class="contain">
<canvas nx="dial" class="widg"></canvas>
<p>frequency</p>
</div>
<div class="contain">
<canvas nx="dial" class="widg"></canvas>
<p>volume</p>
</div>
</div>
<footer>
<p>GendyJS is a project of <a href="http://www.andrewbernste.in">Andrew Bernstein</a></p>
<a href="http://www.github.com/abbernie/gendy"><img src="fork.png" id="fork"></img></a>
</footer>
</body>
<script>
nx.onload = function(){
nx.sendsTo("js");
nx.showLabels = "true";
nx.colorize("#0000a0");
toggle1.on('*',function(){
if(toggle1.val.value == 1){
pressed();
init(num);
} else if(toggle1.val.value == 0){
stop();
}
});
number1.label = "# of Breakpoints";
console.log(nx.showLabels);
number1.on("*", function(){
num = Math.floor(number1.val.value);
});
number1.set({value:15});
dial1.label = "x step";
console.log(nx.showLabels);
dial1.on("*", function(){
xStep = dial1.val.value * 50;
console.log(xStep);
});
dial1.set({value:0}, true);
dial2.on("*", function(){
yMax = dial2.val.value;
yMin = dial2.val.value*(-1);
console.log(yMax);
});
dial2.set({value:0.5},true);
dial3.on("*", function(){
yStep = dial3.val.value;
console.log(yStep);
});
dial3.set({value:0.015},true);
dial4.on("*", function(){
freq = dial4.val.value*10;
console.log(freq);
});
dial4.set({value:0.1},true);
dial5.on("*", function(){
vol = dial5.val.value;
console.log(vol);
});
dial5.set({value:0.5},true);
}
var canvas = document.getElementById("canvas");
var context = canvas.getContext('2d');
canvas.width = 800;
canvas.height = 300
/*
*
*
* AUDIO SYNTHESIS CODE
*
*
*/
var actx = new (AudioContext || wedkitAudioContext)();
var gain = actx.createGain();
gain.gain.value = 0;
var gain2 = actx.createGain();
var vol = 0.5;
gain2.gain.value = vol;
var scriptNode = actx.createScriptProcessor(512,1,1);
gain.connect(gain2);
gain2.connect(actx.destination);
var breakpoint = [];
var xStep = 1;
var xRoom = 10;
var yMax = 0.5;
var yMin = -0.5;
var yStep = 0.01;
var y = 0;
var point = 0;
var index = 0;
var freq = 1;
var num = 15;
var waveformlength = 850;
function init(breakpoints){
var lastX = 0;
var last = 0;
breakpoint = []
for(var i = 0;i < breakpoints;i++){
if(i == 0){
//generate breakpoints
breakpoint[0] = {
x : 0.0,
y : 0.0,
x1 : 0.0,
y1 : 0.0,
m : 0.0,
b : 0.0
};
} else if(i != 0){
breakpoint[i] = {};
breakpoint[i].x = ((waveformlength/breakpoints)*i);
/* if(breakpoint[i].x >= scriptNode.bufferSize){
breakpoint[i].x = scriptNode.bufferSize-10;
} */
lastX = breakpoint[i].x;
breakpoint[i].y = (Math.random()*2)-1;
if(i == breakpoints-1){
breakpoint[i].y = 0;
}
breakpoint[i].x1 = breakpoint[last].x;
breakpoint[i].y1 = breakpoint[last].y;
breakpoint[i].m = (breakpoint[i].y-breakpoint[last].y1)/(breakpoint[i].x-breakpoint[last].x1);
breakpoint[i].b = breakpoint[i].y-(breakpoint[i].m*breakpoint[i].x);
last = i;
} else if(i == breakpoints-1){
breakpoint[i].y = 0;
}
}
num = breakpoint.length
walk()
}
function walk(){
if (num != breakpoint.length) {
init(num);
}
var last = 0;
var next = 1;
for(var i = 0; i < breakpoint.length;i++){
if(i != 0){
var randomx = Math.floor(Math.random()*2);
var x = breakpoint[i].x;
if(i != breakpoint.length-1){
breakpoint[i].xMax = breakpoint[next].x-xRoom;
} else {
// breakpoint[i].xMax = scriptNode.bufferSize-xRoom;
breakpoint[i].xMax = waveformlength;
}
breakpoint[i].xMin = breakpoint[last].x+xRoom;
// the random walk, 2 samples in either direction
if(randomx == 0){
x = x - xStep;
} else if(randomx == 1){
x = x + xStep;
}
//bounds on the random walk, if it goes out of bounds, it jumps the difference back in
if(x >= breakpoint[i].xMax-xRoom){
x = breakpoint[i].xMax-xRoom;
} else if(x <= breakpoint[i].xMin+xRoom){
x = breakpoint[i].xMin+xRoom;
}
breakpoint[i].x = x;
var randomy = Math.floor(Math.random()*2);
var y = breakpoint[i].y;
if(randomy == 0){
y = y - yStep;
} else if(randomy == 1){
y = y + yStep;
}
if(y > yMax){
y = yMax-(y-yMax);
} else if(y < yMin){
y = yMin-(y-yMin);
}
breakpoint[i].y = y;
}
last = i;
next++;
}
breakpoint[0].y = 0;
breakpoint[breakpoint.length-1].y = 0;
convertBreakpoints();
}
function convertBreakpoints() {
testpts = []
for (var i=0;i<breakpoint.length;i++) {
testpts.push(breakpoint[i].x)
testpts.push(breakpoint[i].y)
}
spline = getCurvePoints(testpts, 0.5, false, 16)
}
scriptNode.onaudioprocess = function(audioProcessingEvent){
context.globalAlpha = 0.5;
context.fillStyle = "#fff"
context.fillRect(0,0,canvas.width,canvas.height);
var outputBuffer = audioProcessingEvent.outputBuffer;
var outputData = outputBuffer.getChannelData(0);
for(var j = 0; j < outputData.length;j++){
if(point < spline.length && index >= spline[point+1].x) {
while (index > spline[point+1].x) {
point++;
if (point > spline.length) { break; }
}
}
// linearly interpolate between the new breakpoint positions
// get the interp point by comparing index to the x distance
var lerp = (index - spline[point].x) / (spline[point+1].x - spline[point].x)
y = lerp * (spline[point+1].y - spline[point].y) + spline[point].y;
outputData[j] = y;
index+=freq;
if(index >= spline[spline.length-1].x){
index = 0;
point = 0;
walk();
}
context.globalAlpha = 1;
context.fillStyle = "#0000a0";
context.fillRect(index,y*canvas.height+canvas.height/2,5,5);
}
}
function connect(output){
scriptNode.connect(output);
}
function disconnect(output){
scriptNode.disconnect(output);
}
function pressed(){
gain.gain.setValueAtTime(0.0,actx.currentTime);
connect(gain);
gain.gain.linearRampToValueAtTime(1.0, actx.currentTime+5.0);
}
function stop(){
disconnect(gain);
}
function getCurvePoints(pts, tension, isClosed, numOfSegments) {
// use input value if provided, or use a default value
tension = (typeof tension != 'undefined') ? tension : 0.5;
isClosed = isClosed ? isClosed : false;
numOfSegments = numOfSegments ? numOfSegments : 16;
var _pts = [], res = [], // clone array
x, y, // our x,y coords
t1x, t2x, t1y, t2y, // tension vectors
c1, c2, c3, c4, // cardinal points
st, t, i; // steps based on num. of segments
// clone array so we don't change the original
_pts = pts.slice(0);
// The algorithm require a previous and next point to the actual point array.
// Check if we will draw closed or open curve.
// If closed, copy end points to beginning and first points to end
// If open, duplicate first points to befinning, end points to end
if (isClosed) {
_pts.unshift(pts[pts.length - 1]);
_pts.unshift(pts[pts.length - 2]);
_pts.unshift(pts[pts.length - 1]);
_pts.unshift(pts[pts.length - 2]);
_pts.push(pts[0]);
_pts.push(pts[1]);
}
else {
_pts.unshift(pts[1]); //copy 1. point and insert at beginning
_pts.unshift(pts[0]);
_pts.push(pts[pts.length - 2]); //copy last point and append
_pts.push(pts[pts.length - 1]);
}
// ok, lets start..
// 1. loop goes through point array
// 2. loop goes through each segment between the 2 pts + 1e point before and after
for (i=2; i < (_pts.length - 4); i+=2) {
for (t=0; t <= numOfSegments; t++) {
// calc tension vectors
t1x = (_pts[i+2] - _pts[i-2]) * tension;
t2x = (_pts[i+4] - _pts[i]) * tension;
t1y = (_pts[i+3] - _pts[i-1]) * tension;
t2y = (_pts[i+5] - _pts[i+1]) * tension;
// calc step
st = t / numOfSegments;
// calc cardinals
c1 = 2 * Math.pow(st, 3) - 3 * Math.pow(st, 2) + 1;
c2 = -(2 * Math.pow(st, 3)) + 3 * Math.pow(st, 2);
c3 = Math.pow(st, 3) - 2 * Math.pow(st, 2) + st;
c4 = Math.pow(st, 3) - Math.pow(st, 2);
// calc x and y cords with common control vectors
x = c1 * _pts[i] + c2 * _pts[i+2] + c3 * t1x + c4 * t2x;
y = c1 * _pts[i+1] + c2 * _pts[i+3] + c3 * t1y + c4 * t2y;
//store points in array
res.push({x: x, y: y});
}
}
return res;
}
</script>
</html>