first-commit

skills/html-ppt/assets/animations/fx/particle-burst.js

@@ -0,0 +1,42 @@
+(function(){
+  window.HPX = window.HPX || {};
+  window.HPX['particle-burst'] = function(el){
+    const U = window.HPX._u;
+    const k = U.canvas(el), ctx = k.ctx;
+    const pal = U.palette(el);
+    let parts = [];
+    const spawn = () => {
+      const cx = k.w/2, cy = k.h/2;
+      const n = 90;
+      for (let i=0;i<n;i++){
+        const a = Math.random()*Math.PI*2;
+        const s = U.rand(80, 260);
+        parts.push({
+          x: cx, y: cy,
+          vx: Math.cos(a)*s, vy: Math.sin(a)*s,
+          life: 1, r: U.rand(2,5),
+          c: pal[(Math.random()*pal.length)|0]
+        });
+      }
+    };
+    spawn();
+    let lastSpawn = 0;
+    const stop = U.loop((t) => {
+      ctx.clearRect(0,0,k.w,k.h);
+      if (t - lastSpawn > 2.5) { spawn(); lastSpawn = t; }
+      const dt = 1/60;
+      parts = parts.filter(p => p.life > 0);
+      for (const p of parts){
+        p.vy += 220*dt;
+        p.vx *= 0.985; p.vy *= 0.985;
+        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, p.r, 0, Math.PI*2); ctx.fill();
+      }
+      ctx.globalAlpha = 1;
+    });
+    return { stop(){ stop(); k.destroy(); } };
+  };
+})();