# Objective
- In particularly dark scenes, auto-exposure would lead to an unexpected
darkening of the view.
- Fixes#13446.
## Solution
The average luminance should default to something else than 0.0 instead,
when there are no samples. We set it to `settings.min_log_lum`.
## Testing
I was able to reproduce the problem on the `auto_exposure` example by
setting the point light intensity to 2000 and looking into the
right-hand corner. There was a sudden darkening.
Now, the discontinuity is gone.
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Co-authored-by: Alice Cecile <alice.i.cecil@gmail.com>
Co-authored-by: Bram Buurlage <brambuurlage@gmail.com>
# Objective
- Add auto exposure/eye adaptation to the bevy render pipeline.
- Support features that users might expect from other engines:
- Metering masks
- Compensation curves
- Smooth exposure transitions
This PR is based on an implementation I already built for a personal
project before https://github.com/bevyengine/bevy/pull/8809 was
submitted, so I wasn't able to adopt that PR in the proper way. I've
still drawn inspiration from it, so @fintelia should be credited as
well.
## Solution
An auto exposure compute shader builds a 64 bin histogram of the scene's
luminance, and then adjusts the exposure based on that histogram. Using
a histogram allows the system to ignore outliers like shadows and
specular highlights, and it allows to give more weight to certain areas
based on a mask.
---
## Changelog
- Added: AutoExposure plugin that allows to adjust a camera's exposure
based on it's scene's luminance.
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Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
