Fast and Gorgeous Erosion Filter

2 days ago

The blog post introduces an erosion technique that produces realistic-looking gullies and ridges in virtual landscapes without simulating water drops.
The technique builds on earlier work by Clay John and Fewes, refining and evolving the approach over eight months.
Key improvements include two approaches: the 'frequency approach' from earlier versions and a new 'fade approach' developed by the author.
The fade approach preserves crisp peaks and valleys by fading gullies towards a target value based on altitude, avoiding bulges at valleys.
Three techniques enhance crispness: stacked fading, normalized gullies, and straight gullies to create cleaner branching patterns.
Normalized gullies ensure consistent magnitude using Phacelle Noise, while straight gullies prevent curling by faking consistent slopes.
Additional features include pointy peaks adjustment, rounding of ridges and creases for realism, and water drainage simulation using a ridge map.
The final iteration is shared via Shadertoys and open-sourced under the Mozilla Public License v2, encouraging further development.
Practical applications and examples from others are mentioned, along with tools for rendering Shadertoys footage.

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