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实例教程 HTML5 Canvas 超炫酷烟花绽放动画实现代码_html5教程技巧

程序员文章站 2022-03-11 21:21:36
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　　这是一个很酷的HTML5 Canvas动画，它将模拟的是我们现实生活中烟花绽放的动画特效，效果非常逼真，但是毕竟是电脑模拟，带女朋友看就算了，效果还是差了点，呵呵。这个HTML5 Canvas动画有一点比较出色，就是其性能，Chrome上基本没有卡的感觉，就算你放出很多烟花也一样。

实例教程 HTML5 Canvas 超炫酷烟花绽放动画实现代码_html5教程技巧

　　下面我们来简单分析一下实现这款HTML5烟花特效的过程及代码，主要由HTML代码、CSS代码以及Javascript代码组成，当然javascript代码是最重要的。

　　HTML代码：

XML/HTML Code复制内容到剪贴板
  1. div id=”gui”>div>
  2. div id=”canvas-container”> div id=”mountains2″>div>
  3. div id=”mountains1″>div>div id=”skyline”>div> div>

　　HTML的结构非常简单，即构造了一个canvas容器，我们会利用JS在这个容器中生成一个Canvas对象。看最后的JS代码你就会知道了。

　　CSS代码：

CSS Code复制内容到剪贴板
  1. #canvas-container { background: #000 url(bg.jpg); height: 400px; left: 50%; margin: -200px 0 0 -300px; position: absolute; top: 50%; width: 600px; z-index: 2;
  2. } canvas { cursor: crosshair; display: block; position: relative; z-index: 3;
  3. } canvas:active { cursor: crosshair;
  4. } #skyline { background: url(skyline.png) repeat-x 50% 0; bottombottom: 0; height: 135px; left: 0; position: absolute; width: 100%; z-index: 1;
  5. } #mountains1 { background: url(mountains1.png) repeat-x 40% 0; bottombottom: 0; height: 200px; left: 0; position: absolute; width: 100%; z-index: 1;
  6. } #mountains2 { background: url(mountains2.png) repeat-x 30% 0; bottombottom: 0; height: 250px; left: 0; position: absolute; width: 100%; z-index: 1;
  7. } #gui { rightright: 0; position: fixed; top: 0; z-index: 3;
  8. }

　　CSS代码没什么特别，主要也就定义一下背景色和边框之类的。

　　接下来是最重要的Javascript代码。

　　Javascript代码：

JavaScript Code复制内容到剪贴板
  1. self.init = function(){
  2. self.dt = 0;
  3. self.oldTime = Date.now();
  4. self.canvas = document.createElement('canvas');
  5. self.canvasContainer = $('#canvas-container'); var canvasContainerDisabled = document.getElementById('canvas-container');
  6. self.canvas.onselectstart = function() { return false;
  7. };
  9. self.canvas.width = self.cw = 600;
  10. self.canvas.height = self.ch = 400;
  12. self.particles = [];
  13. self.partCount = 30;
  14. self.fireworks = [];
  15. self.mx = self.cw/2;
  16. self.my = self.ch/2;
  17. self.currentHue = 170;
  18. self.partSpeed = 5;
  19. self.partSpeedVariance = 10;
  20. self.partWind = 50;
  21. self.partFriction = 5;
  22. self.partGravity = 1;
  23. self.hueMin = 150;
  24. self.hueMax = 200;
  25. self.fworkSpeed = 2;
  26. self.fworkAccel = 4;
  27. self.hueVariance = 30;
  28. self.flickerDensity = 20;
  29. self.showShockwave = false;
  30. self.showTarget = true;
  31. self.clearAlpha = 25;
  33. self.canvasContainer.append(self.canvas);
  34. self.ctx = self.canvas.getContext('2d');
  35. self.ctx.lineCap = 'round';
  36. self.ctx.lineJoin = 'round';
  37. self.lineWidth = 1;
  38. self.bindEvents();
  39. self.canvasLoop();
  41. self.canvas.onselectstart = function() { return false;
  42. };
  44. };

　　这段JS代码主要是往canvas容器中构造一个Canvas对象，并且对这个canvas对象的外观以及动画属性作了初始化。

JavaScript Code复制内容到剪贴板
  1. var Particle = function(x, y, hue){ this.x = x; this.y = y; this.coordLast = [
  2. {x: x, y: y},
  3. {x: x, y: y},
  4. {x: x, y: y}
  5. ]; this.angle = rand(0, 360); this.speed = rand(((self.partSpeed - self.partSpeedVariance) this.friction = 1 - self.partFriction/100; this.gravity = self.partGravity/2; this.hue = rand(hue-self.hueVariance, hue+self.hueVariance); this.brightness = rand(50, 80); this.alpha = rand(40,100)/100; this.decay = rand(10, 50)/1000; this.wind = (rand(0, self.partWind) - (self.partWind/2))/25; this.lineWidth = self.lineWidth;
  6. };
  8. Particle.prototype.update = function(index){ var radians = this.angle * Math.PI / 180; var vx = Math.cos(radians) * this.speed; var vy = Math.sin(radians) * this.speed + this.gravity; this.speed *= this.friction; this.coordLast[2].x = this.coordLast[1].x; this.coordLast[2].y = this.coordLast[1].y; this.coordLast[1].x = this.coordLast[0].x; this.coordLast[1].y = this.coordLast[0].y; this.coordLast[0].x = this.x; this.coordLast[0].y = this.y; this.x += vx * self.dt; this.y += vy * self.dt; this.angle += this.wind; this.alpha -= this.decay; if(!hitTest(0,0,self.cw,self.ch,this.x-this.radius, this.y-this.radius, this.radius*2, this.radius*2) || this.alpha
  9. self.particles.splice(index, 1);
  10. }
  11. };
  13. Particle.prototype.draw = function(){ var coordRand = (rand(1,3)-1);
  14. self.ctx.beginPath();
  15. self.ctx.moveTo(Math.round(this.coordLast[coordRand].x), Math.round(this.coordLast[coordRand].y));
  16. self.ctx.lineTo(Math.round(this.x), Math.round(this.y));
  17. self.ctx.closePath();
  18. self.ctx.strokeStyle = 'hsla('+this.hue+', 100%, '+this.brightness+'%, '+this.alpha+')';
  19. self.ctx.stroke(); if(self.flickerDensity > 0){ var inverseDensity = 50 - self.flickerDensity; if(rand(0, inverseDensity) === inverseDensity){
  20. self.ctx.beginPath();
  21. self.ctx.arc(Math.round(this.x), Math.round(this.y), rand(this.lineWidth,this.lineWidth+3)/2, 0, Math.PI*2, false) self.ctx.closePath(); var randAlpha = rand(50,100)/100;
  22. self.ctx.fillStyle = 'hsla('+this.hue+', 100%, '+this.brightness+'%, '+randAlpha+')';
  23. self.ctx.fill();
  24. }
  25. }
  26. };

　　这段JS代码的功能是实现烟花爆炸后的小颗粒的绘制，从draw方法中可以看出，创建几个随机点，烟花颗粒即可在这个范围的随机点中散落。

JavaScript Code复制内容到剪贴板
  1. var Firework = function(startX, startY, targetX, targetY){ this.x = startX; this.y = startY; this.startX = startX; this.startY = startY; this.hitX = false; this.hitY = false; this.coordLast = [
  2. {x: startX, y: startY},
  3. {x: startX, y: startY},
  4. {x: startX, y: startY}
  5. ]; this.targetX = targetX; this.targetY = targetY; this.speed = self.fworkSpeed; this.angle = Math.atan2(targetY - startY, targetX - startX); this.shockwaveAngle = Math.atan2(targetY - startY, targetX - startX)+(90*(Math.PI/180)); this.acceleration = self.fworkAccel/100; this.hue = self.currentHue; this.brightness = rand(50, 80); this.alpha = rand(50,100)/100; this.lineWidth = self.lineWidth; this.targetRadius = 1;
  6. };
  8. Firework.prototype.update = function(index){
  9. self.ctx.lineWidth = this.lineWidth;
  11. vx = Math.cos(this.angle) * this.speed,
  12. vy = Math.sin(this.angle) * this.speed; this.speed *= 1 + this.acceleration; this.coordLast[2].x = this.coordLast[1].x; this.coordLast[2].y = this.coordLast[1].y; this.coordLast[1].x = this.coordLast[0].x; this.coordLast[1].y = this.coordLast[0].y; this.coordLast[0].x = this.x; this.coordLast[0].y = this.y; if(self.showTarget){ if(this.targetRadius this.targetRadius += .25 * self.dt;
  13. } else { this.targetRadius = 1 * self.dt;
  14. }
  15. } if(this.startX >= this.targetX){ if(this.x + vx this.targetX){ this.x = this.targetX; this.hitX = true;
  16. } else { this.x += vx * self.dt;
  17. }
  18. } else { if(this.x + vx >= this.targetX){ this.x = this.targetX; this.hitX = true;
  19. } else { this.x += vx * self.dt;
  20. }
  21. } if(this.startY >= this.targetY){ if(this.y + vy this.targetY){ this.y = this.targetY; this.hitY = true;
  22. } else { this.y += vy * self.dt;
  23. }
  24. } else { if(this.y + vy >= this.targetY){ this.y = this.targetY; this.hitY = true;
  25. } else { this.y += vy * self.dt;
  26. }
  27. } if(this.hitX && this.hitY){ var randExplosion = rand(0, 9);
  28. self.createParticles(this.targetX, this.targetY, this.hue);
  29. self.fireworks.splice(index, 1);
  30. }
  31. };
  33. Firework.prototype.draw = function(){
  34. self.ctx.lineWidth = this.lineWidth; var coordRand = (rand(1,3)-1);
  35. self.ctx.beginPath();
  36. self.ctx.moveTo(Math.round(this.coordLast[coordRand].x), Math.round(this.coordLast[coordRand].y));
  37. self.ctx.lineTo(Math.round(this.x), Math.round(this.y));
  38. self.ctx.closePath();
  39. self.ctx.strokeStyle = 'hsla('+this.hue+', 100%, '+this.brightness+'%, '+this.alpha+')';
  40. self.ctx.stroke(); if(self.showTarget){
  41. self.ctx.save();
  42. self.ctx.beginPath();
  43. self.ctx.arc(Math.round(this.targetX), Math.round(this.targetY), this.targetRadius, 0, Math.PI*2, false)
  44. self.ctx.closePath();
  45. self.ctx.lineWidth = 1;
  46. self.ctx.stroke();
  47. self.ctx.restore();
  48. } if(self.showShockwave){
  49. self.ctx.save();
  50. self.ctx.translate(Math.round(this.x), Math.round(this.y));
  51. self.ctx.rotate(this.shockwaveAngle);
  52. self.ctx.beginPath();
  53. self.ctx.arc(0, 0, 1*(this.speed/5), 0, Math.PI, true);
  54. self.ctx.strokeStyle = 'hsla('+this.hue+', 100%, '+this.brightness+'%, '+rand(25, 60)/100+')';
  55. self.ctx.lineWidth = this.lineWidth;
  56. self.ctx.stroke();
  57. self.ctx.restore();
  58. }
  59. };

　　这段JS代码是创建烟花实例的，我们也可以从draw方法中看出，当我们鼠标点击画布中的某点时，烟花发射的目的地就在那个点上。

　　这款HTML5 Canvas烟花效果的核心代码就是这样，谢谢阅读，希望能帮到大家，请继续关注脚本之家，我们会努力分享更多优秀的文章。

相关标签： html5烟花绽放效果 html5canvas HTML5动画教程

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