Cet article présente principalement le JS+HTML5 natif pour réaliser l'effet d'animation de particules qui circule avec la souris, impliquant une réponse aux événements javascript, une opération numérique et une opération dynamique des techniques d'implémentation liées aux attributs des éléments de page. Les amis dans le besoin peuvent s'y référer. 🎜>
L'exemple de cet article décrit l'utilisation de JS+HTML5 natifs pour obtenir des effets d'animation de particules qui suivent la souris. Partagez-le avec tout le monde pour votre référence, les détails sont les suivants :<!DOCTYPE html> <html lang="en"> <head> <meta charset=gbk> <title>www.jb51.net 粒子效果演示</title> <meta name="description" content="HTML5/canvas demo, 500 particles to play around with." /> <meta name="keywords" content="html5,canvas,javascript,particles,interactive,velocity,programming,flash" /> <style type="text/css"> html, body { text-align: center; margin:0; padding:0; background: #000000; color: #666666; line-height: 1.25em; } #outer { position: absolute; top: 50%; left: 50%; width: 1px; height: 1px; overflow: visible; } #canvasContainer { position: absolute; width: 1000px; height: 560px; top: -280px; left: -500px; } canvas { border: 1px solid #333333; } a { color: #00CBCB; text-decoration:none; font-weight:bold; } a:hover { color:#FFFFFF; } #output { font-family: Arial, Helvetica, sans-serif; font-size: 0.75em; margin-top:4px; } #footer{ font-size: 0.6em; font-family: Arial, Helvetica, sans-serif; position: absolute; bottombottom:8px; width:98%; } </style> </head> <body> <p id="outer"> <p id="canvasContainer"> <canvas id="mainCanvas" width="1000" height="560"></canvas> <p id="output"></p> </p> </p> <script type="text/javascript"> //javascript部分 (function(){ var PI_2 = Math.PI * 2; var canvasW = 1000; var canvasH = 560; var numMovers = 600; var friction = 0.96; var movers = []; var canvas; var ctx; var canvasp; var outerp; var mouseX; var mouseY; var mouseVX; var mouseVY; var prevMouseX; var prevMouseY; var isMouseDown; function init(){ canvas = document.getElementById("mainCanvas"); if ( canvas.getContext ){ setup(); setInterval( run , 33 ); trace('你们好'); } else{ trace("Sorry, needs a recent version of Chrome, Firefox, Opera, Safari, or Internet Explorer 9."); } } function setup(){ outerp = document.getElementById("outer"); canvasp = document.getElementById("canvasContainer"); ctx = canvas.getContext("2d"); var i = numMovers; while ( i-- ){ var m = new Mover(); m.x = canvasW * 0.5; m.y = canvasH * 0.5; m.vX = Math.cos(i) * Math.random() * 34; m.vY = Math.sin(i) * Math.random() * 34; movers[i] = m; } mouseX = prevMouseX = canvasW * 0.5; mouseY = prevMouseY = canvasH * 0.5; document.onmousedown = onDocMouseDown; document.onmouseup = onDocMouseUp; document.onmousemove = onDocMouseMove; } function run(){ ctx.globalCompositeOperation = "source-over"; ctx.fillStyle = "rgba(8,8,12,0.65)"; ctx.fillRect( 0 , 0 , canvasW , canvasH ); ctx.globalCompositeOperation = "lighter"; mouseVX = mouseX - prevMouseX; mouseVY = mouseY - prevMouseY; prevMouseX = mouseX; prevMouseY = mouseY; var toDist = canvasW * 0.86; var stirDist = canvasW * 0.125; var blowDist = canvasW * 0.5; var Mrnd = Math.random; var Mabs = Math.abs; var i = numMovers; while ( i-- ){ var m = movers[i]; var x = m.x; var y = m.y; var vX = m.vX; var vY = m.vY; var dX = x - mouseX; var dY = y - mouseY; var d = Math.sqrt( dX * dX + dY * dY ) || 0.001; dX /= d; dY /= d; if ( isMouseDown ){ if ( d < blowDist ){ var blowAcc = ( 1 - ( d / blowDist ) ) * 14; vX += dX * blowAcc + 0.5 - Mrnd(); vY += dY * blowAcc + 0.5 - Mrnd(); } } if ( d < toDist ){ var toAcc = ( 1 - ( d / toDist ) ) * canvasW * 0.0014; vX -= dX * toAcc; vY -= dY * toAcc; } if ( d < stirDist ){ var mAcc = ( 1 - ( d / stirDist ) ) * canvasW * 0.00026; vX += mouseVX * mAcc; vY += mouseVY * mAcc; } vX *= friction; vY *= friction; var avgVX = Mabs( vX ); var avgVY = Mabs( vY ); var avgV = ( avgVX + avgVY ) * 0.5; if( avgVX < .1 ) vX *= Mrnd() * 3; if( avgVY < .1 ) vY *= Mrnd() * 3; var sc = avgV * 0.45; sc = Math.max( Math.min( sc , 3.5 ) , 0.4 ); var nextX = x + vX; var nextY = y + vY; if ( nextX > canvasW ){ nextX = canvasW; vX *= -1; } else if ( nextX < 0 ){ nextX = 0; vX *= -1; } if ( nextY > canvasH ){ nextY = canvasH; vY *= -1; } else if ( nextY < 0 ){ nextY = 0; vY *= -1; } m.vX = vX; m.vY = vY; m.x = nextX; m.y = nextY; ctx.fillStyle = m.color; ctx.beginPath(); ctx.arc( nextX , nextY , sc , 0 , PI_2 , true ); ctx.closePath(); ctx.fill(); } } function onDocMouseMove( e ){ var ev = e ? e : window.event; mouseX = ev.clientX - outerp.offsetLeft - canvasp.offsetLeft; mouseY = ev.clientY - outerp.offsetTop - canvasp.offsetTop; } function onDocMouseDown( e ){ isMouseDown = true; return false; } function onDocMouseUp( e ){ isMouseDown = false; return false; } function Mover(){ this.color = "rgb(" + Math.floor( Math.random()*255 ) + "," + Math.floor( Math.random()*255 ) + "," + Math.floor( Math.random()*255 ) + ")"; this.y = 0; this.x = 0; this.vX = 0; this.vY = 0; this.size = 1; } function rect( context , x , y , w , h ){ context.beginPath(); context.rect( x , y , w , h ); context.closePath(); context.fill(); } function trace( str ){ document.getElementById("output").innerHTML = str; } window.onload = init; })(); </script> </body> </html>
Effet d'animation de chute de flocon de neige réalisé par JS natif
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