first-commit

skills/html-ppt/assets/animations/fx/firework.js

@@ -0,0 +1,51 @@
+(function(){
+  window.HPX = window.HPX || {};
+  window.HPX['firework'] = function(el){
+    const U = window.HPX._u;
+    const k = U.canvas(el), ctx = k.ctx;
+    const pal = U.palette(el);
+    let rockets = [], sparks = [];
+    const launch = () => {
+      rockets.push({
+        x: U.rand(k.w*0.2, k.w*0.8), y: k.h+10,
+        vx: U.rand(-30,30), vy: U.rand(-520,-380),
+        tgtY: U.rand(k.h*0.15, k.h*0.45),
+        c: pal[(Math.random()*pal.length)|0]
+      });
+    };
+    const burst = (x, y, c) => {
+      const n = 70;
+      for (let i=0;i<n;i++){
+        const a = Math.random()*Math.PI*2;
+        const s = U.rand(60, 240);
+        sparks.push({x,y,vx:Math.cos(a)*s,vy:Math.sin(a)*s,life:1,c});
+      }
+    };
+    let last = -1;
+    const stop = U.loop((t) => {
+      ctx.fillStyle = 'rgba(0,0,0,0.18)';
+      ctx.fillRect(0,0,k.w,k.h);
+      if (t - last > 0.7) { launch(); last = t; }
+      const dt = 1/60;
+      rockets = rockets.filter(r => {
+        r.x += r.vx*dt; r.y += r.vy*dt; r.vy += 260*dt;
+        ctx.fillStyle = r.c;
+        ctx.beginPath(); ctx.arc(r.x, r.y, 2.5, 0, Math.PI*2); ctx.fill();
+        if (r.y <= r.tgtY || r.vy >= 0) { burst(r.x, r.y, r.c); return false; }
+        return true;
+      });
+      sparks = sparks.filter(p => p.life > 0);
+      for (const p of sparks){
+        p.vy += 90*dt;
+        p.vx *= 0.98; p.vy *= 0.98;
+        p.x += p.vx*dt; p.y += p.vy*dt;
+        p.life -= 0.012;
+        ctx.globalAlpha = Math.max(0, p.life);
+        ctx.fillStyle = p.c;
+        ctx.beginPath(); ctx.arc(p.x, p.y, 2, 0, Math.PI*2); ctx.fill();
+      }
+      ctx.globalAlpha = 1;
+    });
+    return { stop(){ stop(); k.destroy(); } };
+  };
+})();