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Diffstat (limited to 'docs/assets/js/util.js')
| -rw-r--r-- | docs/assets/js/util.js | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/docs/assets/js/util.js b/docs/assets/js/util.js new file mode 100644 index 0000000..e40db4a --- /dev/null +++ b/docs/assets/js/util.js @@ -0,0 +1,139 @@ +const is_iphone = (navigator.userAgent.match(/iPhone/i)) || (navigator.userAgent.match(/iPod/i)) +const is_ipad = (navigator.userAgent.match(/iPad/i)) +const is_android = (navigator.userAgent.match(/Android/i)) +const is_mobile = is_iphone || is_ipad || is_android +const is_desktop = !is_mobile; +document.body.parentNode.classList.add(is_desktop ? 'desktop' : 'mobile') + +function avg(a,b,n){ return (a*(n-1) + b)/n } +function rand(n){ return Math.random()*n } +function randint(n) { return ~~(Math.random()*n) } +function randrange(a,b){ return a+rand(b-a) } +function choice(a) { return a[randint(a.length)] } +function clamp(n,a,b) { return a > n ? a : n > b ? b : n } +function sign(n){ return n < 0 ? -1 : 1 } +function mod(n,m){ return n-(m * Math.floor(n/m)) } +function lerp(n,a,b){ return (b-a)*n+a } +function quantize(m,n){ return n * ((m/n)|0) } + +function randgauss (obj, jog) { + var radius = Math.random() * jog + var angle = Math.random() * Math.PI * 2 + obj.left += Math.sin(angle) * radius + obj.top += Math.cos(angle) * radius +} + +function shuffle(a){ + for (var i = a.length; i > 0; i--){ + var r = randint(i) + var swap = a[i-1] + a[i-1] = a[r] + a[r] = swap + } + return a +} + +function toArray (els){ + return Array.prototype.slice.apply(els) +} + +// easing functions +function circular (t) { return Math.sqrt( 1 - ( --t * t ) ) } +function quadratic (t) { return t * ( 2 - t ) } +function back (t) { + var b = 4; + return ( t = t - 1 ) * t * ( ( b + 1 ) * t + b ) + 1; +} +function bounce (t) { + if (t >= 1) return 1; + if ( ( t /= 1 ) < ( 1 / 2.75 ) ) { + return 7.5625 * t * t; + } else if ( t < ( 2 / 2.75 ) ) { + return 7.5625 * ( t -= ( 1.5 / 2.75 ) ) * t + 0.75; + } else if ( t < ( 2.5 / 2.75 ) ) { + return 7.5625 * ( t -= ( 2.25 / 2.75 ) ) * t + 0.9375; + } else { + return 7.5625 * ( t -= ( 2.625 / 2.75 ) ) * t + 0.984375; + } +} +function elastic (t) { + var f = 0.22, + e = 0.4; + + if ( t === 0 ) { return 0; } + if ( t == 1 ) { return 1; } + + return ( e * Math.pow( 2, - 10 * t ) * Math.sin( ( t - f / 4 ) * ( 2 * Math.PI ) / f ) + 1 ); +} + +function preload (url) { + var img = new Image () + var loaded = false, _cb + img.onload = function(){ + if (loaded) return + loaded = true + if (_cb) { _cb(img) } + } + img.src = url + if (img.complete) { img.onload() } + return { + then: function(cb){ + if (loaded) { cb(img) } + else { _cb = cb } + } + } +} + +function preloadImages () { + var images = toArray(document.getElementById("images").children) + var count = 0, ready = false, _cb + images.forEach(function(img){ + var loaded = false + img.onload = function(){ + if (loaded) return + loaded = true + done(img) + } + if (img.complete) { img.onload() } + }) + function done () { + if (++count == images.length && ! ready) { + ready = true + _cb && _cb() + } + } + return { + then: function(cb){ + if (ready) { cb() } + else { _cb = cb } + } + } +} + +function smoothstep(min,max,n){ + var t = clamp((n - min) / (max - min), 0.0, 1.0); + return t * t * (3.0 - 2.0 * t) +} + +function detrand (x,y) { + return (Math.sin( x * 12.9898 + y * 78.233 ) * 43758.5453) % 1 +} + +function gray_to_transparency(img) { + var canvas = document.createElement("canvas") + var ctx = canvas.getContext('2d') + var nw = img.naturalWidth, nh = img.naturalHeight + canvas.width = nw + canvas.height = nh + ctx.drawImage(img,0,0) + var pixels = ctx.getImageData(0,0,nw,nh) + var data = pixels.data + for (var i = 0, len = nw*nh*4; i < len; i += 4) { + data[i+3] = data[i] + data[i] = data[i+1] = data[i+2] = 255 + } + ctx.putImageData(pixels,0,0) + return canvas +} + +var TWO_PI = 2*Math.PI
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