52 lines
1.6 KiB
JavaScript
52 lines
1.6 KiB
JavaScript
(function(){
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window.HPX = window.HPX || {};
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window.HPX['firework'] = function(el){
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const U = window.HPX._u;
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const k = U.canvas(el), ctx = k.ctx;
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const pal = U.palette(el);
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let rockets = [], sparks = [];
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const launch = () => {
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rockets.push({
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x: U.rand(k.w*0.2, k.w*0.8), y: k.h+10,
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vx: U.rand(-30,30), vy: U.rand(-520,-380),
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tgtY: U.rand(k.h*0.15, k.h*0.45),
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c: pal[(Math.random()*pal.length)|0]
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});
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};
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const burst = (x, y, c) => {
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const n = 70;
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for (let i=0;i<n;i++){
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const a = Math.random()*Math.PI*2;
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const s = U.rand(60, 240);
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sparks.push({x,y,vx:Math.cos(a)*s,vy:Math.sin(a)*s,life:1,c});
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}
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};
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let last = -1;
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const stop = U.loop((t) => {
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ctx.fillStyle = 'rgba(0,0,0,0.18)';
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ctx.fillRect(0,0,k.w,k.h);
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if (t - last > 0.7) { launch(); last = t; }
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const dt = 1/60;
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rockets = rockets.filter(r => {
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r.x += r.vx*dt; r.y += r.vy*dt; r.vy += 260*dt;
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ctx.fillStyle = r.c;
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ctx.beginPath(); ctx.arc(r.x, r.y, 2.5, 0, Math.PI*2); ctx.fill();
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if (r.y <= r.tgtY || r.vy >= 0) { burst(r.x, r.y, r.c); return false; }
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return true;
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});
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sparks = sparks.filter(p => p.life > 0);
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for (const p of sparks){
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p.vy += 90*dt;
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p.vx *= 0.98; p.vy *= 0.98;
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p.x += p.vx*dt; p.y += p.vy*dt;
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p.life -= 0.012;
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ctx.globalAlpha = Math.max(0, p.life);
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ctx.fillStyle = p.c;
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ctx.beginPath(); ctx.arc(p.x, p.y, 2, 0, Math.PI*2); ctx.fill();
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}
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ctx.globalAlpha = 1;
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});
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return { stop(){ stop(); k.destroy(); } };
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};
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})();
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