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Diffstat (limited to 'rickroll/main.js')
| -rw-r--r-- | rickroll/main.js | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/rickroll/main.js b/rickroll/main.js new file mode 100644 index 0000000..8f867fb --- /dev/null +++ b/rickroll/main.js @@ -0,0 +1,66 @@ +const css = window.document.styleSheets[0] + + +let currentTarget={ + fromLeft: 5, + toLeft: 5, // left: 5%; + fromTop:25, + toTop: 25, // top: 25%; + time: 0, +} + +function genTarget(){ + currentTarget.fromLeft = currentTarget.toLeft; + currentTarget.fromTop = currentTarget.toTop; + currentTarget.toLeft = 5 + (randn_bm() - 0.5)*10 + currentTarget.toTop = 25 + (randn_bm()-0.5)*10 + currentTarget.time = randn_bm() * 0.4 +0.05 +} +cssIndex = undefined; + +const toMove = document.getElementById("indihome-content"); +let keyframeId = 0; +function move(){ + genTarget() + if(cssIndex!=undefined){ + css.deleteRule(cssIndex) + } + cssIndex = css.cssRules.length + toMove.style.animation = "" + css.insertRule( + "@keyframes move"+keyframeId+" {\n" + + " 0% {\n" + + " left: "+currentTarget.fromLeft+"%;\n" + + " top: "+currentTarget.fromTop+"%;\n" + + " }\n" + + " 100% {\n" + + " left: "+currentTarget.toLeft+"%;\n" + + " top: "+currentTarget.toTop+"%;\n" + + " }\n" + + "}" + ,cssIndex) + + toMove.style.animation = "move"+keyframeId+" "+currentTarget.time+"s linear" + keyframeId++; +} + +function moveLoop(){ + move() + setTimeout(moveLoop, currentTarget.time*1000) +} +moveLoop() + + +/** + * this code uses the Box–Muller transform to give you a normal distribution between 0 and 1 inclusive. + * https://stackoverflow.com/questions/25582882/javascript-math-random-normal-distribution-gaussian-bell-curve + */ +function randn_bm() { + let u = 0, v = 0; + while(u === 0) u = Math.random(); //Converting [0,1) to (0,1) + while(v === 0) v = Math.random(); + let num = Math.sqrt( -2.0 * Math.log( u ) ) * Math.cos( 2.0 * Math.PI * v ); + num = num / 10.0 + 0.5; // Translate to 0 -> 1 + if (num > 1 || num < 0) return randn_bm() // resample between 0 and 1 + return num +}
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