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    javascript实现超好看的3D烟花特效

    栏目:代码类 时间:2020-01-01 18:10

    本文实例为大家分享了超好看3D烟花的具体代码,供大家参考,具体内容如下

    <!doctype html>
    <html>
    <head>
    <meta charset="utf-8">
    <title>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 ></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>
    <div >
    </div>
    </body>
    </html>