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Caustics - Free Online | FunToolX

Use Caustics online for free, no download required. FunToolX offers hundreds of fun online tools.

Sunlight refracting through the water surface casts shifting caustic light webs on the seabed. Tap Tint to change the water colour.

About this tool

Caustics is a free online visual effect. Simulates sunlight refracting through water, casting shifting web-like light patterns on the seabed. Interactive eye-candy rendered live on your screen. It runs entirely in your browser — no download or sign-up needed.

After opening the page, it will display the caustic spot effect produced by light passing through the water surface or glass. The spot forms beautiful patterns on the water bottom or on the desktop. Parameters such as light source position, refractive index, and caustic intensity can be adjusted.

The entire process is pure front-end animation, with a WebGL-based shader program that uses a simplified version of photon mapping to simulate caustics.

Suitable for underwater theme decoration, optical display, or purely appreciating the beautiful effects of caustics spots. The implementation principle is a simplified photon mapping algorithm.

Caustics is a visual effect that simulates the caustic spot effect produced by light passing through a transparent object. It is rendered in real time based on a WebGL shader.