bevy/assets
Patrick Walton 961b24deaf
Implement filmic color grading. (#13121)
This commit expands Bevy's existing tonemapping feature to a complete
set of filmic color grading tools, matching those of engines like Unity,
Unreal, and Godot. The following features are supported:

* White point adjustment. This is inspired by Unity's implementation of
the feature, but simplified and optimized. *Temperature* and *tint*
control the adjustments to the *x* and *y* chromaticity values of [CIE
1931]. Following Unity, the adjustments are made relative to the [D65
standard illuminant] in the [LMS color space].

* Hue rotation. This simply converts the RGB value to [HSV], alters the
hue, and converts back.

* Color correction. This allows the *gamma*, *gain*, and *lift* values
to be adjusted according to the standard [ASC CDL combined function].

* Separate color correction for shadows, midtones, and highlights.
Blender's source code was used as a reference for the implementation of
this. The midtone ranges can be adjusted by the user. To avoid abrupt
color changes, a small crossfade is used between the different sections
of the image, again following Blender's formulas.

A new example, `color_grading`, has been added, offering a GUI to change
all the color grading settings. It uses the same test scene as the
existing `tonemapping` example, which has been factored out into a
shared glTF scene.

[CIE 1931]: https://en.wikipedia.org/wiki/CIE_1931_color_space

[D65 standard illuminant]:
https://en.wikipedia.org/wiki/Standard_illuminant#Illuminant_series_D

[LMS color space]: https://en.wikipedia.org/wiki/LMS_color_space

[HSV]: https://en.wikipedia.org/wiki/HSL_and_HSV

[ASC CDL combined function]:
https://en.wikipedia.org/wiki/ASC_CDL#Combined_Function

## Changelog

### Added

* Many new filmic color grading options have been added to the
`ColorGrading` component.

## Migration Guide

* `ColorGrading::gamma` and `ColorGrading::pre_saturation` are now set
separately for the `shadows`, `midtones`, and `highlights` sections. You
can migrate code with the `ColorGrading::all_sections` and
`ColorGrading::all_sections_mut` functions, which access and/or update
all sections at once.
* `ColorGrading::post_saturation` and `ColorGrading::exposure` are now
fields of `ColorGrading::global`.

## Screenshots

![Screenshot 2024-04-27
143144](https://github.com/bevyengine/bevy/assets/157897/c1de5894-917d-4101-b5c9-e644d141a941)

![Screenshot 2024-04-27
143216](https://github.com/bevyengine/bevy/assets/157897/da393c8a-d747-42f5-b47c-6465044c788d)
2024-05-02 12:18:59 +00:00
..
android-res/mipmap-mdpi android example polish (#845) 2020-11-11 16:31:16 -08:00
animation_graphs Implement the AnimationGraph, allowing for multiple animations to be blended together. (#11989) 2024-03-07 20:22:42 +00:00
branding Remove unused namespace declarations (#10965) 2023-12-13 22:29:16 +00:00
data Added Support for Extension-less Assets (#10153) 2024-01-31 14:58:08 +00:00
docs Improve Mesh documentation (#9061) 2023-07-31 18:55:42 +00:00
environment_maps Implement minimal reflection probes (fixed macOS, iOS, and Android). (#11366) 2024-01-19 07:33:52 +00:00
fonts Add the license for the FiraMono font (#3589) 2022-05-06 19:29:43 +00:00
irradiance_volumes Implement irradiance volumes. (#10268) 2024-02-06 23:23:20 +00:00
lightmaps Implement lightmaps. (#10231) 2024-01-02 20:38:47 +00:00
models Implement filmic color grading. (#13121) 2024-05-02 12:18:59 +00:00
pixel Add example for pixel-perfect grid snapping in 2D (#8112) 2023-12-26 17:15:50 +00:00
scenes Fix scene example (#11289) 2024-01-22 15:14:41 +00:00
shaders Fix example game of life (#12897) 2024-04-08 17:19:07 +00:00
sounds Programmed soundtrack example (#12774) 2024-03-29 20:32:30 +00:00
textures Slicing support for texture atlas (#12059) 2024-03-05 16:05:39 +00:00