Вращающаяся сфера из частиц на HTML5 и jQuery
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<canvas id="canvasOne" width="900" height="520"></canvas></script> |
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<script> window.addEventListener("load", windowLoadHandler, false); var sphereRad = 300; var radius_sp = 1; //for debug messages var Debugger = function() {}; Debugger.log = function(message) { try { console.log(message); } catch (exception) { return; } } function windowLoadHandler() { canvasApp(); } function canvasSupport() { return Modernizr.canvas; } function canvasApp() { if (!canvasSupport()) { return; } var theCanvas = document.getElementById("canvasOne"); var context = theCanvas.getContext("2d"); var displayWidth; var displayHeight; var timer; var wait; var count; var numToAddEachFrame; var particleList; var recycleBin; var particleAlpha; var r, g, b; var fLen; var m; var projCenterX; var projCenterY; var zMax; var turnAngle; var turnSpeed; var sphereCenterX, sphereCenterY, sphereCenterZ; var particleRad; var zeroAlphaDepth; var randAccelX, randAccelY, randAccelZ; var gravity; var rgbString; //we are defining a lot of variables used in the screen update functions globally so that they don't have to be redefined every frame. var p; var outsideTest; var nextParticle; var sinAngle; var cosAngle; var rotX, rotZ; var depthAlphaFactor; var i; var theta, phi; var x0, y0, z0; init(); function init() { wait = 2; count = wait - 1; numToAddEachFrame = 1; //particle color r = 70; g = 255; b = 140; rgbString = "rgba(" + r + "," + g + "," + b + ","; //partial string for color which will be completed by appending alpha value. particleAlpha = 1; //maximum alpha displayWidth = theCanvas.width; displayHeight = theCanvas.height; fLen = 320; //represents the distance from the viewer to z=0 depth. //projection center coordinates sets location of origin projCenterX = displayWidth / 2; projCenterY = displayHeight / 2; //we will not draw coordinates if they have too large of a z-coordinate (which means they are very close to the observer). zMax = fLen - 2; particleList = {}; recycleBin = {}; //random acceleration factors - causes some random motion randAccelX = 0.1; randAccelY = 0.1; randAccelZ = 0.1; gravity = -0; //try changing to a positive number (not too large, for example 0.3), or negative for floating upwards. particleRad = 2.5; sphereCenterX = 0; sphereCenterY = 0; sphereCenterZ = -3 - sphereRad; //alpha values will lessen as particles move further back, causing depth-based darkening: zeroAlphaDepth = -750; turnSpeed = 2 * Math.PI / 5000; //the sphere will rotate at this speed (one complete rotation every 1600 frames). turnAngle = 0; //initial angle timer = setInterval(onTimer, 10 / 24); } function onTimer() { //if enough time has elapsed, we will add new particles. count++; if (count >= wait) { count = 0; for (i = 0; i < numToAddEachFrame; i++) { theta = Math.random() * 2 * Math.PI; phi = Math.acos(Math.random() * 2 - 1); x0 = sphereRad * Math.sin(phi) * Math.cos(theta); y0 = sphereRad * Math.sin(phi) * Math.sin(theta); z0 = sphereRad * Math.cos(phi); //We use the addParticle function to add a new particle. The parameters set the position and velocity components. //Note that the velocity parameters will cause the particle to initially fly outwards away from the sphere center (after //it becomes unstuck). var p = addParticle(x0, sphereCenterY + y0, sphereCenterZ + z0, 0.002 * x0, 0.002 * y0, 0.002 * z0); //we set some "envelope" parameters which will control the evolving alpha of the particles. p.attack = 50; p.hold = 50; p.decay = 100; p.initValue = 0; p.holdValue = particleAlpha; p.lastValue = 0; //the particle will be stuck in one place until this time has elapsed: p.stuckTime = 90 + Math.random() * 20; p.accelX = 0; p.accelY = gravity; p.accelZ = 0; } } //update viewing angle turnAngle = (turnAngle + turnSpeed) % (2 * Math.PI); sinAngle = Math.sin(turnAngle); cosAngle = Math.cos(turnAngle); //background fill context.fillStyle = "#000000"; context.fillRect(0, 0, displayWidth, displayHeight); //update and draw particles p = particleList.first; while (p != null) { //before list is altered record next particle nextParticle = p.next; //update age p.age++; //if the particle is past its "stuck" time, it will begin to move. if (p.age > p.stuckTime) { p.velX += p.accelX + randAccelX * (Math.random() * 2 - 1); p.velY += p.accelY + randAccelY * (Math.random() * 2 - 1); p.velZ += p.accelZ + randAccelZ * (Math.random() * 2 - 1); p.x += p.velX; p.y += p.velY; p.z += p.velZ; } /* We are doing two things here to calculate display coordinates. The whole display is being rotated around a vertical axis, so we first calculate rotated coordinates for x and z (but the y coordinate will not change). Then, we take the new coordinates (rotX, y, rotZ), and project these onto the 2D view plane. */ rotX = cosAngle * p.x + sinAngle * (p.z - sphereCenterZ); rotZ = -sinAngle * p.x + cosAngle * (p.z - sphereCenterZ) + sphereCenterZ; m = radius_sp * fLen / (fLen - rotZ); p.projX = rotX * m + projCenterX; p.projY = p.y * m + projCenterY; //update alpha according to envelope parameters. if (p.age < p.attack + p.hold + p.decay) { if (p.age < p.attack) { p.alpha = (p.holdValue - p.initValue) / p.attack * p.age + p.initValue; } else if (p.age < p.attack + p.hold) { p.alpha = p.holdValue; } else if (p.age < p.attack + p.hold + p.decay) { p.alpha = (p.lastValue - p.holdValue) / p.decay * (p.age - p.attack - p.hold) + p.holdValue; } } else { p.dead = true; } //see if the particle is still within the viewable range. if ((p.projX > displayWidth) || (p.projX < 0) || (p.projY < 0) || (p.projY > displayHeight) || (rotZ > zMax)) { outsideTest = true; } else { outsideTest = false; } if (outsideTest || p.dead) { recycle(p); } else { //depth-dependent darkening depthAlphaFactor = (1 - rotZ / zeroAlphaDepth); depthAlphaFactor = (depthAlphaFactor > 1) ? 1 : ((depthAlphaFactor < 0) ? 0 : depthAlphaFactor); context.fillStyle = rgbString + depthAlphaFactor * p.alpha + ")"; //draw context.beginPath(); context.arc(p.projX, p.projY, m * particleRad, 0, 2 * Math.PI, false); context.closePath(); context.fill(); } p = nextParticle; } } function addParticle(x0, y0, z0, vx0, vy0, vz0) { var newParticle; var color; //check recycle bin for available drop: if (recycleBin.first != null) { newParticle = recycleBin.first; //remove from bin if (newParticle.next != null) { recycleBin.first = newParticle.next; newParticle.next.prev = null; } else { recycleBin.first = null; } } //if the recycle bin is empty, create a new particle (a new ampty object): else { newParticle = {}; } //add to beginning of particle list if (particleList.first == null) { particleList.first = newParticle; newParticle.prev = null; newParticle.next = null; } else { newParticle.next = particleList.first; particleList.first.prev = newParticle; particleList.first = newParticle; newParticle.prev = null; } //initialize newParticle.x = x0; newParticle.y = y0; newParticle.z = z0; newParticle.velX = vx0; newParticle.velY = vy0; newParticle.velZ = vz0; newParticle.age = 0; newParticle.dead = false; if (Math.random() < 0.5) { newParticle.right = true; } else { newParticle.right = false; } return newParticle; } function recycle(p) { //remove from particleList if (particleList.first == p) { if (p.next != null) { p.next.prev = null; particleList.first = p.next; } else { particleList.first = null; } } else { if (p.next == null) { p.prev.next = null; } else { p.prev.next = p.next; p.next.prev = p.prev; } } //add to recycle bin if (recycleBin.first == null) { recycleBin.first = p; p.prev = null; p.next = null; } else { p.next = recycleBin.first; recycleBin.first.prev = p; recycleBin.first = p; p.prev = null; } } } $(function() { $("#slider-range").slider({ range: false, min: 20, max: 500, value: 280, slide: function(event, ui) { console.log(ui.value); sphereRad = ui.value; } }); }); $(function() { $("#slider-test").slider({ range: false, min: 1.0, max: 2.0, value: 1, step: 0.01, slide: function(event, ui) { radius_sp = ui.value; } }); }); </script> |