本文實例為大家分享了javascript實現3D煙花特效的具體代碼，供大家參考，具體內容如下
<!DOCTYPE html><html> <head> <meta charset="utf-8" /> <title></title> <meta charset="utf-8"><title>3D煙花</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>以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持VeVb武林網。
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