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web前端学习教程 -前端工程师带你用JAVASCRIPT和html5打造不同的炫酷烟花效果

web前端开发html2019-04-18 12:03:49

先看下效果:


源码展示:

<!doctype html>

<html>

<head>

<meta charset="utf-8">

<title>Canvas绘制3D烟花动画特效</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"></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)?pic1:pic2];

break;

case 2:

switch(parseInt(Math.random()*3)){

case 0: spark.img=sparkPics[pic1]; break;

case 1: spark.img=sparkPics[pic2]; break;

case 2: spark.img=sparkPics[pic3]; break;

}

break;

}

spark.radius=25+Math.random()*50;

spark.alpha=1;

spark.trail=new Array();

sparks.push(spark);

}

switch(parseInt(Math.random()*4)){

case 0: pow=new Audio(s+"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>

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