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新年快乐! javascript实现超级炫酷的3D烟花特效

2019年03月17日  | 移动技术网IT编程  | 我要评论

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)?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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