In this post, I’ll walk you through how to create a custom shader in Three.js that simulates the look of a foil sticker, complete with angle-dependent iridescence and sparkling metallic flakes. The goal is to capture that premium, holographic effect you see on collectible stickers, trading cards, and high-end packaging, but to render it in real time directly in the browser. Iridescence If you’ve ever tilted a holographic sticker or watched sunlight catch on a soap bubble, you’ve seen ir...