用p5.js制作烟花特效的示例代码

function setup() { //processing初始化设置 createCanvas(window.innerWidth, window.innerHeight); frameRate(50); imageMode(CENTER);}function draw() { //循环执行，达成画面渲染效果 background(0, 0, 40); for (var i = 0; i < fireworks.length; i++) {  fireworks[i].display();  fireworks[i].update();  if (fireworks[i].needRemove()) {   fireworks.splice(i, 1);  } }}

function Fireworks(radius) { var num = 512; //一发烟花里，有多少个点 (比较吃机器) var centerPosition = new p5.Vector(random(width / 8, width * 7 / 8), random(height / 2, height * 4 / 5), random(-100, 100)); //烟花的中心位置 var velocity = new p5.Vector(0, -22, 0); var accel = new p5.Vector(0, 0.4, 0); var img; var firePosition = []; var cosTheta; var sinTheta; var phi; var colorChange = random(0, 5); for (var i = 0; i < num; i++) {  cosTheta = random(0, 1) * 2 - 1;  sinTheta = sqrt(1 - cosTheta * cosTheta);  phi = random(0, 1) * 2 * PI;  firePosition[i] = new p5.Vector(radius * sinTheta * cos(phi), radius * sinTheta * sin(phi), radius * cosTheta); //1发烟花里各个点的位置计算  firePosition[i] = p5.Vector.mult(firePosition[i], 1.12); } //调整烟花随机颜色，使其更亮丽 if(colorChange>=3.8){  img=createLight(0.9,random(0.2,0.5),random(0.2,0.5)); }else if(colorChange>3.2){  img=createLight(random(0.2,0.5),0.9,random(0.2,0.5)); }else if(colorChange>2){  img=createLight(random(0.2,0.5),random(0.2,0.5),0.9); } else {  img=createLight(random(0.5,0.8),random(0.5,0.8),random(0.5,0.8)); } this.display = function () {  for (var i = 0; i < num; i++) {   push();   translate(centerPosition.x, centerPosition.y, centerPosition.z);   translate(firePosition[i].x, firePosition[i].y, firePosition[i].z);   blendMode(ADD); //各个小点（发光源遮罩效果）   image(img, 0, 0);   pop();   firePosition[i] = p5.Vector.mult(firePosition[i], 1.015); //更新小点（发光源）扩散位置  }  } this.update = function () { //模拟重力加速度  radius = dist(0, 0, 0, firePosition[0].x, firePosition[0].y, firePosition[0].z);  centerPosition.add(velocity);  velocity.add(accel); } this.needRemove = function () {  if (centerPosition.y - radius > height) {   return true;  } else {   return false;  } }}

function createLight(rPower, gPower, bPower) { var side = 64; var center = side / 2.0; var img = createImage(side, side); img.loadPixels(); for (var y = 0; y < side; y++) {  for (var x = 0; x < side; x++) {   var distance = (sq(center - x) + sq(center - y)) / 10.0;   var r = int((255 * rPower) / distance);   var g = int((255 * gPower) / distance);   var b = int((255 * bPower) / distance);   // img.pixels[x + y * side] = color(r, g, b);   img.set(y, x, color(r, g, b));  } } img.updatePixels(); return img;}

function keyPressed() { //每事件添加一发烟花 fireworks.push(new Fireworks(80)); //80为烟花初始半径}function touchStarted() { //每事件添加一发烟花 fireworks.push(new Fireworks(80)); return false;}