Clamp F_ab.x in specular multiscatter to fix grazing angle artifacts #22833
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# Objective The F_AB() polynomial approximation produces F_ab.x values approaching zero or slightly negative on highly reflective surfaces viewed at grazing angles, causing fireflies and black pixelated aliasing. ## Solution Clamp F_ab.x to a minimum of 0.1. ## Testing - `cargo run --example atmosphere` (with free camera to get grazing angle with water) --- ## Showcase Before: <img width="1542" height="561" alt="image" src="https://github.com/user-attachments/assets/b9649267-4dbc-4623-8938-9012d5059e3f" /> After: <img width="1768" height="688" alt="image" src="https://github.com/user-attachments/assets/709c070a-4366-49fe-882d-ad9e1c2f1edb" />
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Objective
The F_AB() polynomial approximation produces F_ab.x values approaching zero or slightly negative on highly reflective surfaces viewed at grazing angles, causing fireflies and black pixelated aliasing.
Solution
Clamp F_ab.x to a minimum of 0.1.
Testing
cargo run --example atmosphere(with free camera to get grazing angle with water)Showcase
Before:
After: