bevy/examples/3d
Patrick Walton 77ed72bc16
Implement clearcoat per the Filament and the KHR_materials_clearcoat specifications. (#13031)
Clearcoat is a separate material layer that represents a thin
translucent layer of a material. Examples include (from the [Filament
spec]) car paint, soda cans, and lacquered wood. This commit implements
support for clearcoat following the Filament and Khronos specifications,
marking the beginnings of support for multiple PBR layers in Bevy.

The [`KHR_materials_clearcoat`] specification describes the clearcoat
support in glTF. In Blender, applying a clearcoat to the Principled BSDF
node causes the clearcoat settings to be exported via this extension. As
of this commit, Bevy parses and reads the extension data when present in
glTF. Note that the `gltf` crate has no support for
`KHR_materials_clearcoat`; this patch therefore implements the JSON
semantics manually.

Clearcoat is integrated with `StandardMaterial`, but the code is behind
a series of `#ifdef`s that only activate when clearcoat is present.
Additionally, the `pbr_feature_layer_material_textures` Cargo feature
must be active in order to enable support for clearcoat factor maps,
clearcoat roughness maps, and clearcoat normal maps. This approach
mirrors the same pattern used by the existing transmission feature and
exists to avoid running out of texture bindings on platforms like WebGL
and WebGPU. Note that constant clearcoat factors and roughness values
*are* supported in the browser; only the relatively-less-common maps are
disabled on those platforms.

This patch refactors the lighting code in `StandardMaterial`
significantly in order to better support multiple layers in a natural
way. That code was due for a refactor in any case, so this is a nice
improvement.

A new demo, `clearcoat`, has been added. It's based on [the
corresponding three.js demo], but all the assets (aside from the skybox
and environment map) are my original work.

[Filament spec]:
https://google.github.io/filament/Filament.html#materialsystem/clearcoatmodel

[`KHR_materials_clearcoat`]:
https://github.com/KhronosGroup/glTF/blob/main/extensions/2.0/Khronos/KHR_materials_clearcoat/README.md

[the corresponding three.js demo]:
https://threejs.org/examples/webgl_materials_physical_clearcoat.html

![Screenshot 2024-04-19
101143](https://github.com/bevyengine/bevy/assets/157897/3444bcb5-5c20-490c-b0ad-53759bd47ae2)

![Screenshot 2024-04-19
102054](https://github.com/bevyengine/bevy/assets/157897/6e953944-75b8-49ef-bc71-97b0a53b3a27)

## Changelog

### Added

* `StandardMaterial` now supports a clearcoat layer, which represents a
thin translucent layer over an underlying material.
* The glTF loader now supports the `KHR_materials_clearcoat` extension,
representing materials with clearcoat layers.

## Migration Guide

* The lighting functions in the `pbr_lighting` WGSL module now have
clearcoat parameters, if `STANDARD_MATERIAL_CLEARCOAT` is defined.

* The `R` reflection vector parameter has been removed from some
lighting functions, as it was unused.
2024-05-05 22:57:05 +00:00
..
3d_scene.rs Migrate from LegacyColor to bevy_color::Color (#12163) 2024-02-29 19:35:12 +00:00
3d_shapes.rs Implement percentage-closer filtering (PCF) for point lights. (#12910) 2024-04-10 20:16:08 +00:00
3d_viewport_to_world.rs separating finite and infinite 3d planes (#12426) 2024-04-18 14:13:22 +00:00
animated_material.rs Add hue traits (#12399) 2024-03-22 00:36:46 +00:00
anti_aliasing.rs Migrate from LegacyColor to bevy_color::Color (#12163) 2024-02-29 19:35:12 +00:00
atmospheric_fog.rs Migrate from LegacyColor to bevy_color::Color (#12163) 2024-02-29 19:35:12 +00:00
auto_exposure.rs Implement Auto Exposure plugin (#12792) 2024-05-03 17:45:17 +00:00
blend_modes.rs Migrate from LegacyColor to bevy_color::Color (#12163) 2024-02-29 19:35:12 +00:00
bloom_3d.rs Improve Bloom 3D lighting (#11981) 2024-03-07 15:20:38 +00:00
clearcoat.rs Implement clearcoat per the Filament and the KHR_materials_clearcoat specifications. (#13031) 2024-05-05 22:57:05 +00:00
color_grading.rs Fix CI error on new color grading example (#13180) 2024-05-02 13:40:45 +00:00
deferred_rendering.rs Implement GPU frustum culling. (#12889) 2024-04-28 12:50:00 +00:00
fog.rs Migrate from LegacyColor to bevy_color::Color (#12163) 2024-02-29 19:35:12 +00:00
generate_custom_mesh.rs Clarify comment about camera coordinate system (#13056) 2024-04-23 14:58:28 +00:00
irradiance_volumes.rs separating finite and infinite 3d planes (#12426) 2024-04-18 14:13:22 +00:00
lighting.rs Fix pink colors in examples (#12451) 2024-03-18 17:44:46 +00:00
lightmaps.rs fix example lightmaps after color migration (#12265) 2024-03-03 21:36:11 +00:00
lines.rs Intern mesh vertex buffer layouts so that we don't have to compare them over and over. (#12216) 2024-03-01 20:56:21 +00:00
load_gltf.rs New Exposure and Lighting Defaults (and calibrate examples) (#11868) 2024-02-15 20:42:48 +00:00
meshlet.rs Example setup for tooling (#13088) 2024-05-02 20:10:09 +00:00
motion_blur.rs Per-Object Motion Blur (#9924) 2024-04-25 01:16:02 +00:00
orthographic.rs Migrate from LegacyColor to bevy_color::Color (#12163) 2024-02-29 19:35:12 +00:00
parallax_mapping.rs Move close_on_esc to bevy_dev_tools (#12855) 2024-04-03 01:29:06 +00:00
parenting.rs Migrate from LegacyColor to bevy_color::Color (#12163) 2024-02-29 19:35:12 +00:00
pbr.rs Migrate from LegacyColor to bevy_color::Color (#12163) 2024-02-29 19:35:12 +00:00
reflection_probes.rs Migrate from LegacyColor to bevy_color::Color (#12163) 2024-02-29 19:35:12 +00:00
render_to_texture.rs Migrate from LegacyColor to bevy_color::Color (#12163) 2024-02-29 19:35:12 +00:00
shadow_biases.rs Implement percentage-closer filtering (PCF) for point lights. (#12910) 2024-04-10 20:16:08 +00:00
shadow_caster_receiver.rs Remove redundant imports (#12817) 2024-04-01 19:59:08 +00:00
skybox.rs Migrate from LegacyColor to bevy_color::Color (#12163) 2024-02-29 19:35:12 +00:00
spherical_area_lights.rs Migrate from LegacyColor to bevy_color::Color (#12163) 2024-02-29 19:35:12 +00:00
split_screen.rs Fix "dark grey" colors becoming lighter in various examples (#12333) 2024-03-06 05:19:59 +00:00
spotlight.rs Adding explanation to seeded rng used in examples (#12593) 2024-03-26 19:40:18 +00:00
ssao.rs Migrate from LegacyColor to bevy_color::Color (#12163) 2024-02-29 19:35:12 +00:00
texture.rs Migrate from LegacyColor to bevy_color::Color (#12163) 2024-02-29 19:35:12 +00:00
tonemapping.rs Implement filmic color grading. (#13121) 2024-05-02 12:18:59 +00:00
transmission.rs Implement filmic color grading. (#13121) 2024-05-02 12:18:59 +00:00
transparency_3d.rs Implement alpha to coverage (A2C) support. (#12970) 2024-04-15 20:37:52 +00:00
two_passes.rs Migrate from LegacyColor to bevy_color::Color (#12163) 2024-02-29 19:35:12 +00:00
update_gltf_scene.rs New Exposure and Lighting Defaults (and calibrate examples) (#11868) 2024-02-15 20:42:48 +00:00
vertex_colors.rs Migrate from LegacyColor to bevy_color::Color (#12163) 2024-02-29 19:35:12 +00:00
visibility_range.rs Implement visibility ranges, also known as hierarchical levels of detail (HLODs). (#12916) 2024-05-03 00:11:35 +00:00
wireframe.rs Use WireframeColor to override global color (#13034) 2024-04-20 13:59:12 +00:00