本文实例为大家分享了javascript实现3D烟花特效的具体代码，供大家参考，具体内容如下
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title></title>
<meta charset="utf-8">
<title>3D烟花</title>
<style>
html,body{
margin:0px;
width:100%;
height:100%;
overflow:hidden;
background:#000;
}
#canvas{
width:100%;
height:100%;
}
</style>
</head>
<body>
<canvas id="canvas" width="825" height="631"></canvas><script>
function initVars(){
pi=Math.PI;
ctx=canvas.getContext("2d");
canvas.width=canvas.clientWidth;
canvas.height=canvas.clientHeight;
cx=canvas.width/2;
cy=canvas.height/2;
playerZ=-25;
playerX=playerY=playerVX=playerVY=playerVZ=pitch=yaw=pitchV=yawV=0;
scale=600;
seedTimer=0;seedInterval=5,seedLife=100;gravity=.02;
seeds=new Array();
sparkPics=new Array();
s="https://cantelope.org/NYE/";
for(i=1;i<=10;++i){
sparkPic=new Image();
sparkPic.src=s+"spark"+i+".png";
sparkPics.push(sparkPic);
}
sparks=new Array();
pow1=new Audio(s+"pow1.ogg");
pow2=new Audio(s+"pow2.ogg");
pow3=new Audio(s+"pow3.ogg");
pow4=new Audio(s+"pow4.ogg");
frames = 0;
}
function rasterizePoint(x,y,z){
var p,d;
x-=playerX;
y-=playerY;
z-=playerZ;
p=Math.atan2(x,z);
d=Math.sqrt(x*x+z*z);
x=Math.sin(p-yaw)*d;
z=Math.cos(p-yaw)*d;
p=Math.atan2(y,z);
d=Math.sqrt(y*y+z*z);
y=Math.sin(p-pitch)*d;
z=Math.cos(p-pitch)*d;
var rx1=-1000,ry1=1,rx2=1000,ry2=1,rx3=0,ry3=0,rx4=x,ry4=z,uc=(ry4-ry3)*(rx2-rx1)-(rx4-rx3)*(ry2-ry1);
if(!uc) return {x:0,y:0,d:-1};
var ua=((rx4-rx3)*(ry1-ry3)-(ry4-ry3)*(rx1-rx3))/uc;
var ub=((rx2-rx1)*(ry1-ry3)-(ry2-ry1)*(rx1-rx3))/uc;
if(!z)z=.000000001;
if(ua>0&&ua<1&&ub>0&&ub<1){
return {
x:cx+(rx1+ua*(rx2-rx1))*scale,
y:cy+y/z*scale,
d:Math.sqrt(x*x+y*y+z*z)
};
}else{
return {
x:cx+(rx1+ua*(rx2-rx1))*scale,
y:cy+y/z*scale,
d:-1
};
}
}
function spawnSeed(){
seed=new Object();
seed.x=-50+Math.random()*100;
seed.y=25;
seed.z=-50+Math.random()*100;
seed.vx=.1-Math.random()*.2;
seed.vy=-1.5;//*(1+Math.random()/2);
seed.vz=.1-Math.random()*.2;
seed.born=frames;
seeds.push(seed);
}
function splode(x,y,z){
t=5+parseInt(Math.random()*150);
sparkV=1+Math.random()*2.5;
type=parseInt(Math.random()*3);
switch(type){
case 0:
pic1=parseInt(Math.random()*10);
break;
case 1:
pic1=parseInt(Math.random()*10);
do{ pic2=parseInt(Math.random()*10); }while(pic2==pic1);
break;
case 2:
pic1=parseInt(Math.random()*10);
do{ pic2=parseInt(Math.random()*10); }while(pic2==pic1);
do{ pic3=parseInt(Math.random()*10); }while(pic3==pic1 || pic3==pic2);
break;
}
for(m=1;m<t;++m){
spark=new Object();
spark.x=x; spark.y=y; spark.z=z;
p1=pi*2*Math.random();
p2=pi*Math.random();
v=sparkV*(1+Math.random()/6)
spark.vx=Math.sin(p1)*Math.sin(p2)*v;
spark.vz=Math.cos(p1)*Math.sin(p2)*v;
spark.vy=Math.cos(p2)*v;
switch(type){
case 0: spark.img=sparkPics[pic1]; break;
case 1:
spark.img=sparkPics[parseInt(Math.random()*2)"pow1.ogg"); break;
case 1: pow=new Audio(s+"pow2.ogg"); break;
case 2: pow=new Audio(s+"pow3.ogg"); break;
case 3: pow=new Audio(s+"pow4.ogg"); break;
}
d=Math.sqrt((x-playerX)*(x-playerX)+(y-playerY)*(y-playerY)+(z-playerZ)*(z-playerZ));
pow.volume=1.5/(1+d/10);
pow.play();
}
function doLogic(){
if(seedTimer<frames){
seedTimer=frames+seedInterval*Math.random()*10;
spawnSeed();
}
for(i=0;i<seeds.length;++i){
seeds[i].vy+=gravity;
seeds[i].x+=seeds[i].vx;
seeds[i].y+=seeds[i].vy;
seeds[i].z+=seeds[i].vz;
if(frames-seeds[i].born>seedLife){
splode(seeds[i].x,seeds[i].y,seeds[i].z);
seeds.splice(i,1);
}
}
for(i=0;i<sparks.length;++i){
if(sparks[i].alpha>0 && sparks[i].radius>5){
sparks[i].alpha-=.01;
sparks[i].radius/=1.02;
sparks[i].vy+=gravity;
point=new Object();
point.x=sparks[i].x;
point.y=sparks[i].y;
point.z=sparks[i].z;
if(sparks[i].trail.length){
x=sparks[i].trail[sparks[i].trail.length-1].x;
y=sparks[i].trail[sparks[i].trail.length-1].y;
z=sparks[i].trail[sparks[i].trail.length-1].z;
d=((point.x-x)*(point.x-x)+(point.y-y)*(point.y-y)+(point.z-z)*(point.z-z));
if(d>9){
sparks[i].trail.push(point);
}
}else{
sparks[i].trail.push(point);
}
if(sparks[i].trail.length>5)sparks[i].trail.splice(0,1);
sparks[i].x+=sparks[i].vx;
sparks[i].y+=sparks[i].vy;
sparks[i].z+=sparks[i].vz;
sparks[i].vx/=1.075;
sparks[i].vy/=1.075;
sparks[i].vz/=1.075;
}else{
sparks.splice(i,1);
}
}
p=Math.atan2(playerX,playerZ);
d=Math.sqrt(playerX*playerX+playerZ*playerZ);
d+=Math.sin(frames/80)/1.25;
t=Math.sin(frames/200)/40;
playerX=Math.sin(p+t)*d;
playerZ=Math.cos(p+t)*d;
yaw=pi+p+t;
}
function rgb(col){
var r = parseInt((.5+Math.sin(col)*.5)*16);
var g = parseInt((.5+Math.cos(col)*.5)*16);
var b = parseInt((.5-Math.sin(col)*.5)*16);
return "#"+r.toString(16)+g.toString(16)+b.toString(16);
}
function draw(){
ctx.clearRect(0,0,cx*2,cy*2);
ctx.fillStyle="#ff8";
for(i=-100;i<100;i+=3){
for(j=-100;j<100;j+=4){
x=i;z=j;y=25;
point=rasterizePoint(x,y,z);
if(point.d!=-1){
size=250/(1+point.d);
d = Math.sqrt(x * x + z * z);
a = 0.75 - Math.pow(d / 100, 6) * 0.75;
if(a>0){
ctx.globalAlpha = a;
ctx.fillRect(point.x-size/2,point.y-size/2,size,size);
}
}
}
}
ctx.globalAlpha=1;
for(i=0;i<seeds.length;++i){
point=rasterizePoint(seeds[i].x,seeds[i].y,seeds[i].z);
if(point.d!=-1){
size=200/(1+point.d);
ctx.fillRect(point.x-size/2,point.y-size/2,size,size);
}
}
point1=new Object();
for(i=0;i<sparks.length;++i){
point=rasterizePoint(sparks[i].x,sparks[i].y,sparks[i].z);
if(point.d!=-1){
size=sparks[i].radius*200/(1+point.d);
if(sparks[i].alpha<0)sparks[i].alpha=0;
if(sparks[i].trail.length){
point1.x=point.x;
point1.y=point.y;
switch(sparks[i].img){
case sparkPics[0]:ctx.strokeStyle="#f84";break;
case sparkPics[1]:ctx.strokeStyle="#84f";break;
case sparkPics[2]:ctx.strokeStyle="#8ff";break;
case sparkPics[3]:ctx.strokeStyle="#fff";break;
case sparkPics[4]:ctx.strokeStyle="#4f8";break;
case sparkPics[5]:ctx.strokeStyle="#f44";break;
case sparkPics[6]:ctx.strokeStyle="#f84";break;
case sparkPics[7]:ctx.strokeStyle="#84f";break;
case sparkPics[8]:ctx.strokeStyle="#fff";break;
case sparkPics[9]:ctx.strokeStyle="#44f";break;
}
for(j=sparks[i].trail.length-1;j>=0;--j){
point2=rasterizePoint(sparks[i].trail[j].x,sparks[i].trail[j].y,sparks[i].trail[j].z);
if(point2.d!=-1){
ctx.globalAlpha=j/sparks[i].trail.length*sparks[i].alpha/2;
ctx.beginPath();
ctx.moveTo(point1.x,point1.y);
ctx.lineWidth=1+sparks[i].radius*10/(sparks[i].trail.length-j)/(1+point2.d);
ctx.lineTo(point2.x,point2.y);
ctx.stroke();
point1.x=point2.x;
point1.y=point2.y;
}
}
}
ctx.globalAlpha=sparks[i].alpha;
ctx.drawImage(sparks[i].img,point.x-size/2,point.y-size/2,size,size);
}
}
}
function frame(){
if(frames>100000){
seedTimer=0;
frames=0;
}
frames++;
draw();
doLogic();
requestAnimationFrame(frame);
}
window.addEventListener("resize",()=>{
canvas.width=canvas.clientWidth;
canvas.height=canvas.clientHeight;
cx=canvas.width/2;
cy=canvas.height/2;
});
initVars();
frame();</script>
</body>
</html>
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。