Chest Open Part 1

Add this game-feel effect to my 2D game: Chest Open — Light Rays.

Reference scene (context only — map it onto my own characters and sizes):
Side-view pixel art on a dusk ground. The hero is 12×13 art pixels drawn at 7px (84×91px); all sizes are screen px at that scale, so scale them to your sprite size. The hero stands on the left; a treasure chest stands 175px to its right, seen from the front and slightly above: 106px wide, 50px-tall front, 22px-thick lid, 44px deep (top shows as a 17px band). Wood #6B4A33, lid top #7D5A3E, lid inside #4A3222, gold #FFC24B trim (12px bands at 20% and 80% of the width, 5px rims, a lock plate), 3px #1A1014 outline. The scene repeats every 1.0s: at t=0 the lid swings back on its rear hinge from 0° to 100° in 0.08s (easeOutCubic 1 − (1 − x)³), showing the dark mouth and a #FFE28C glow (radius 70px); it closes from 0.62s to 0.70s (easeInCubic x³), then stays shut. Point M = chest center x, 58px above the ground. Play the effect below on every open.

The effect:
When the chest opens at t=0, burst rotating god rays from behind it. Center: point M raised 6px. Strength g = easeOutCubic(t/0.15) × (1 − clamp((t − 0.45)/0.17)), where easeOutCubic(x) = 1 − (1 − x)³. It grows in 0.15s, holds, fades linearly from 0.45s to 0.62s, and is 0 after that. Draw 10 rays as thin wedges from the center, length 170px × g, evenly spaced (36° apart). Their half-widths alternate 0.13 and 0.18 radians, and the whole set rotates at 0.9 rad/s (angle = 0.9t + n × 36°). Fill each ray with a gradient from #FFE28C at 75% × g at the center to #FFAA3C at 0% at the tip, with additive blending, and draw the rays behind the chest. On top of the chest, at M raised 12px, add a white 4-point pixel sparkle whose arm length is 30px × sin(π × t/0.5) for t < 0.5s. Its arms are a cross with bar thickness 22% of the arm length (at least 3px) plus a center square twice that thickness. Everything is gone before the lid closes, so it replays cleanly.

Make it a reusable effect with its numbers exposed as parameters, triggered by one call (for example on hit, on pickup or on landing). Use my engine's normal tools (tweens, timers, particles, shaders). If you don't know which engine I use, ask me first.