This commit allows specular highlights to be tinted with a color and for
the reflectance and color tint values to vary across a model via a pair
of maps. The implementation follows the [`KHR_materials_specular`] glTF
extension. In order to reduce the number of samplers and textures in the
default `StandardMaterial` configuration, the maps are gated behind the
`pbr_specular_textures` Cargo feature.
Specular tinting is currently unsupported in the deferred renderer,
because I didn't want to bloat the deferred G-buffers. A possible fix
for this in the future would be to make the G-buffer layout more
configurable, so that specular tints could be supported on an opt-in
basis. As an alternative, Bevy could force meshes with specular tints to
render in forward mode. Both of these solutions require some more
design, so I consider them out of scope for now.
Note that the map is a *specular* map, not a *reflectance* map. In Bevy
and Filament terms, the reflectance values in the specular map range
from [0.0, 0.5], rather than [0.0, 1.0]. This is an unfortunate
[`KHR_materials_specular`] specification requirement that stems from the
fact that glTF is specified in terms of a specular strength model, not
the reflectance model that Filament and Bevy use. A workaround, which is
noted in the `StandardMaterial` documentation, is to set the
`reflectance` value to 2.0, which spreads the specular map range from
[0.0, 1.0] as normal.
The glTF loader has been updated to parse the [`KHR_materials_specular`]
extension. Note that, unless the non-default `pbr_specular_textures` is
supplied, the maps are ignored. The `specularFactor` value is applied as
usual. Note that, as with the specular map, the glTF `specularFactor` is
twice Bevy's `reflectance` value.
This PR adds a new example, `specular_tint`, which demonstrates the
specular tint and map features. Note that this example requires the
[`KHR_materials_specular`] Cargo feature.
[`KHR_materials_specular`]:
https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Khronos/KHR_materials_specular
## Changelog
### Added
* Specular highlights can now be tinted with the `specular_tint` field
in `StandardMaterial`.
* Specular maps are now available in `StandardMaterial`, gated behind
the `pbr_specular_textures` Cargo feature.
* The `KHR_materials_specular` glTF extension is now supported, allowing
for customization of specular reflectance and specular maps. Note that
the latter are gated behind the `pbr_specular_textures` Cargo feature.
# Objective
- Running example `load_gltf` when not using bindless gives this error
```
ERROR bevy_render::render_resource::pipeline_cache: failed to process shader:
error: no definition in scope for identifier: 'slot'
┌─ crates/bevy_pbr/src/render/pbr_fragment.wgsl:153:13
│
153 │ slot,
│ ^^^^ unknown identifier
│
= no definition in scope for identifier: 'slot'
```
- since https://github.com/bevyengine/bevy/pull/16825
## Solution
- Set `slot` to the expected value when not mindless
- Also use it for `uv_b`
## Testing
- Run example `load_gltf` on a Mac or in wasm
This commit allows Bevy to bind 16 lightmaps at a time, if the current
platform supports bindless textures. Naturally, if bindless textures
aren't supported, Bevy falls back to binding only a single lightmap at a
time. As lightmaps are usually heavily atlased, I doubt many scenes will
use more than 16 lightmap textures.
This has little performance impact now, but it's desirable for us to
reap the benefits of multidraw and bindless textures on scenes that use
lightmaps. Otherwise, we might have to break batches in order to switch
those lightmaps.
Additionally, this PR slightly reduces the cost of binning because it
makes the lightmap index in `Opaque3dBinKey` 32 bits instead of an
`AssetId`.
## Migration Guide
* The `Opaque3dBinKey::lightmap_image` field is now
`Opaque3dBinKey::lightmap_slab`, which is a lightweight identifier for
an entire binding array of lightmaps.
This commit makes `StandardMaterial` use bindless textures, as
implemented in PR #16368. Non-bindless mode, as used for example in
Metal and WebGL 2, remains fully supported via a plethora of `#ifdef
BINDLESS` preprocessor definitions.
Unfortunately, this PR introduces quite a bit of unsightliness into the
PBR shaders. This is a result of the fact that WGSL supports neither
passing binding arrays to functions nor passing individual *elements* of
binding arrays to functions, except directly to texture sample
functions. Thus we're unable to use the `sample_texture` abstraction
that helped abstract over the meshlet and non-meshlet paths. I don't
think there's anything we can do to help this other than to suggest
improvements to upstream Naga.
Early implementation. I still have to fix the documentation and consider
writing a small migration guide.
Questions left to answer:
* [x] should thickness be an overridable constant?
* [x] is there a better way to implement `Eq`/`Hash` for `SSAOMethod`?
* [x] do we want to keep the linear sampler for the depth texture?
* [x] is there a better way to separate the logic than preprocessor
macros?
## Migration guide
SSAO algorithm was changed from GTAO to VBAO (visibility bitmasks). A
new field, `constant_object_thickness`, was added to
`ScreenSpaceAmbientOcclusion`. `ScreenSpaceAmbientOcclusion` also lost
its `Eq` and `Hash` implementations.
---------
Co-authored-by: JMS55 <47158642+JMS55@users.noreply.github.com>
* Save 16 bytes per vertex by calculating tangents in the shader at
runtime, rather than storing them in the vertex data.
* Based on https://jcgt.org/published/0009/03/04,
https://www.jeremyong.com/graphics/2023/12/16/surface-gradient-bump-mapping.
* Fixed visbuffer resolve to use the updated algorithm that flips ddy
correctly
* Added some more docs about meshlet material limitations, and some
TODOs about transforming UV coordinates for the future.
For testing add a normal map to the bunnies with StandardMaterial like
below, and then test that on both main and this PR (make sure to
download the correct bunny for each). Results should be mostly
identical.
```rust
normal_map_texture: Some(asset_server.load_with_settings(
"textures/BlueNoise-Normal.png",
|settings: &mut ImageLoaderSettings| settings.is_srgb = false,
)),
```
# Objective
- Standard Material is starting to run out of samplers (currently uses
13 with no additional features off, I think in 0.13 it was 12).
- This change adds a new feature switch, modelled on the other ones
which add features to Standard Material, to turn off the new anisotropy
feature by default.
## Solution
- feature + texture define
## Testing
- Anisotropy example still works fine
- Other samples work fine
- Standard Material now takes 12 samplers by default on my Mac instead
of 13
## Migration Guide
- Add feature pbr_anisotropy_texture if you are using that texture in
any standard materials.
---------
Co-authored-by: John Payne <20407779+johngpayne@users.noreply.github.com>
This commit implements support for physically-based anisotropy in Bevy's
`StandardMaterial`, following the specification for the
[`KHR_materials_anisotropy`] glTF extension.
[*Anisotropy*] (not to be confused with [anisotropic filtering]) is a
PBR feature that allows roughness to vary along the tangent and
bitangent directions of a mesh. In effect, this causes the specular
light to stretch out into lines instead of a round lobe. This is useful
for modeling brushed metal, hair, and similar surfaces. Support for
anisotropy is a common feature in major game and graphics engines;
Unity, Unreal, Godot, three.js, and Blender all support it to varying
degrees.
Two new parameters have been added to `StandardMaterial`:
`anisotropy_strength` and `anisotropy_rotation`. Anisotropy strength,
which ranges from 0 to 1, represents how much the roughness differs
between the tangent and the bitangent of the mesh. In effect, it
controls how stretched the specular highlight is. Anisotropy rotation
allows the roughness direction to differ from the tangent of the model.
In addition to these two fixed parameters, an *anisotropy texture* can
be supplied. Such a texture should be a 3-channel RGB texture, where the
red and green values specify a direction vector using the same
conventions as a normal map ([0, 1] color values map to [-1, 1] vector
values), and the the blue value represents the strength. This matches
the format that the [`KHR_materials_anisotropy`] specification requires.
Such textures should be loaded as linear and not sRGB. Note that this
texture does consume one additional texture binding in the standard
material shader.
The glTF loader has been updated to properly parse the
`KHR_materials_anisotropy` extension.
A new example, `anisotropy`, has been added. This example loads and
displays the barn lamp example from the [`glTF-Sample-Assets`]
repository. Note that the textures were rather large, so I shrunk them
down and converted them to a mixture of JPEG and KTX2 format, in the
interests of saving space in the Bevy repository.
[*Anisotropy*]:
https://google.github.io/filament/Filament.md.html#materialsystem/anisotropicmodel
[anisotropic filtering]:
https://en.wikipedia.org/wiki/Anisotropic_filtering
[`KHR_materials_anisotropy`]:
https://github.com/KhronosGroup/glTF/blob/main/extensions/2.0/Khronos/KHR_materials_anisotropy/README.md
[`glTF-Sample-Assets`]:
https://github.com/KhronosGroup/glTF-Sample-Assets/
## Changelog
### Added
* Physically-based anisotropy is now available for materials, which
enhances the look of surfaces such as brushed metal or hair. glTF scenes
can use the new feature with the `KHR_materials_anisotropy` extension.
## Screenshots
With anisotropy:
Without anisotropy:
# Objective
- Fixes#10909
- Fixes#8492
## Solution
- Name all matrices `x_from_y`, for example `world_from_view`.
## Testing
- I've tested most of the 3D examples. The `lighting` example
particularly should hit a lot of the changes and appears to run fine.
---
## Changelog
- Renamed matrices across the engine to follow a `y_from_x` naming,
making the space conversion more obvious.
## Migration Guide
- `Frustum`'s `from_view_projection`, `from_view_projection_custom_far`
and `from_view_projection_no_far` were renamed to
`from_clip_from_world`, `from_clip_from_world_custom_far` and
`from_clip_from_world_no_far`.
- `ComputedCameraValues::projection_matrix` was renamed to
`clip_from_view`.
- `CameraProjection::get_projection_matrix` was renamed to
`get_clip_from_view` (this affects implementations on `Projection`,
`PerspectiveProjection` and `OrthographicProjection`).
- `ViewRangefinder3d::from_view_matrix` was renamed to
`from_world_from_view`.
- `PreviousViewData`'s members were renamed to `view_from_world` and
`clip_from_world`.
- `ExtractedView`'s `projection`, `transform` and `view_projection` were
renamed to `clip_from_view`, `world_from_view` and `clip_from_world`.
- `ViewUniform`'s `view_proj`, `unjittered_view_proj`,
`inverse_view_proj`, `view`, `inverse_view`, `projection` and
`inverse_projection` were renamed to `clip_from_world`,
`unjittered_clip_from_world`, `world_from_clip`, `world_from_view`,
`view_from_world`, `clip_from_view` and `view_from_clip`.
- `GpuDirectionalCascade::view_projection` was renamed to
`clip_from_world`.
- `MeshTransforms`' `transform` and `previous_transform` were renamed to
`world_from_local` and `previous_world_from_local`.
- `MeshUniform`'s `transform`, `previous_transform`,
`inverse_transpose_model_a` and `inverse_transpose_model_b` were renamed
to `world_from_local`, `previous_world_from_local`,
`local_from_world_transpose_a` and `local_from_world_transpose_b` (the
`Mesh` type in WGSL mirrors this, however `transform` and
`previous_transform` were named `model` and `previous_model`).
- `Mesh2dTransforms::transform` was renamed to `world_from_local`.
- `Mesh2dUniform`'s `transform`, `inverse_transpose_model_a` and
`inverse_transpose_model_b` were renamed to `world_from_local`,
`local_from_world_transpose_a` and `local_from_world_transpose_b` (the
`Mesh2d` type in WGSL mirrors this).
- In WGSL, in `bevy_pbr::mesh_functions`, `get_model_matrix` and
`get_previous_model_matrix` were renamed to `get_world_from_local` and
`get_previous_world_from_local`.
- In WGSL, `bevy_sprite::mesh2d_functions::get_model_matrix` was renamed
to `get_world_from_local`.
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
## 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.
[Alpha to coverage] (A2C) replaces alpha blending with a
hardware-specific multisample coverage mask when multisample
antialiasing is in use. It's a simple form of [order-independent
transparency] that relies on MSAA. ["Anti-aliased Alpha Test: The
Esoteric Alpha To Coverage"] is a good summary of the motivation for and
best practices relating to A2C.
This commit implements alpha to coverage support as a new variant for
`AlphaMode`. You can supply `AlphaMode::AlphaToCoverage` as the
`alpha_mode` field in `StandardMaterial` to use it. When in use, the
standard material shader automatically applies the texture filtering
method from ["Anti-aliased Alpha Test: The Esoteric Alpha To Coverage"].
Objects with alpha-to-coverage materials are binned in the opaque pass,
as they're fully order-independent.
The `transparency_3d` example has been updated to feature an object with
alpha to coverage. Happily, the example was already using MSAA.
This is part of #2223, as far as I can tell.
[Alpha to coverage]: https://en.wikipedia.org/wiki/Alpha_to_coverage
[order-independent transparency]:
https://en.wikipedia.org/wiki/Order-independent_transparency
["Anti-aliased Alpha Test: The Esoteric Alpha To Coverage"]:
https://bgolus.medium.com/anti-aliased-alpha-test-the-esoteric-alpha-to-coverage-8b177335ae4f
---
## Changelog
### Added
* The `AlphaMode` enum now supports `AlphaToCoverage`, to provide
limited order-independent transparency when multisample antialiasing is
in use.
# Objective
- Fixes#12081
## Solution
Passing the `Affine2` as a neatly packed `mat3x2` breaks WebGL with
`drawElementsInstanced: Buffer for uniform block is smaller than
UNIFORM_BLOCK_DATA_SIZE.`
I fixed this by using a `mat3x3` instead.
Alternative solutions that come to mind:
- Pass in a `mat3x2` on non-webgl targets and a `mat3x3` otherwise. I
guess I could use `#ifdef SIXTEEN_BYTE_ALIGNMENT` for this, but it
doesn't seem quite right? This would be more efficient, but decrease
code quality.
- Do something about `UNIFORM_BLOCK_DATA_SIZE`. I don't know how, so I'd
need some guidance here.
@superdump let me know if you'd like me to implement other variants.
Otherwise, I vote for merging this as a quick fix for `main` and then
improving the packing in subsequent PRs :)
## Additional notes
Ideally we should merge this before @JMS55 rebases #10164 so that they
don't have to rebase everything a second time.
Adopted #8266, so copy-pasting the description from there:
# Objective
Support the KHR_texture_transform extension for the glTF loader.
- Fixes#6335
- Fixes#11869
- Implements part of #11350
- Implements the GLTF part of #399
## Solution
As is, this only supports a single transform. Looking at Godot's source,
they support one transform with an optional second one for detail, AO,
and emission. glTF specifies one per texture. The public domain
materials I looked at seem to share the same transform. So maybe having
just one is acceptable for now. I tried to include a warning if multiple
different transforms exist for the same material.
Note the gltf crate doesn't expose the texture transform for the normal
and occlusion textures, which it should, so I just ignored those for
now. (note by @janhohenheim: this is still the case)
Via `cargo run --release --example scene_viewer
~/src/clone/glTF-Sample-Models/2.0/TextureTransformTest/glTF/TextureTransformTest.gltf`:
## Changelog
Support for the
[KHR_texture_transform](https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Khronos/KHR_texture_transform)
extension added. Texture UVs that were scaled, rotated, or offset in a
GLTF are now properly handled.
---------
Co-authored-by: Al McElrath <hello@yrns.org>
Co-authored-by: Kanabenki <lucien.menassol@gmail.com>
# Objective
- Address #10338
## Solution
- When implementing specular and diffuse transmission, I inadvertently
introduced a performance regression. On high-end hardware it is barely
noticeable, but **for lower-end hardware it can be pretty brutal**. If I
understand it correctly, this is likely due to use of masking by the GPU
to implement control flow, which means that you still pay the price for
the branches you don't take;
- To avoid that, this PR introduces new shader defs (controlled via
`StandardMaterialKey`) that conditionally include the transmission
logic, that way the shader code for both types of transmission isn't
even sent to the GPU if you're not using them;
- This PR also renames ~~`STANDARDMATERIAL_NORMAL_MAP`~~ to
`STANDARD_MATERIAL_NORMAL_MAP` for consistency with the naming
convention used elsewhere in the codebase. (Drive-by fix)
---
## Changelog
- Added new shader defs, set when using transmission in the
`StandardMaterial`:
- `STANDARD_MATERIAL_SPECULAR_TRANSMISSION`;
- `STANDARD_MATERIAL_DIFFUSE_TRANSMISSION`;
- `STANDARD_MATERIAL_SPECULAR_OR_DIFFUSE_TRANSMISSION`.
- Fixed performance regression caused by the introduction of
transmission, by gating transmission shader logic behind the newly
introduced shader defs;
- Renamed ~~`STANDARDMATERIAL_NORMAL_MAP`~~ to
`STANDARD_MATERIAL_NORMAL_MAP` for consistency;
## Migration Guide
- If you were using `#ifdef STANDARDMATERIAL_NORMAL_MAP` on your shader
code, make sure to update the name to `STANDARD_MATERIAL_NORMAL_MAP`;
(with an underscore between `STANDARD` and `MATERIAL`)
# Objective
Lightmaps, textures that store baked global illumination, have been a
mainstay of real-time graphics for decades. Bevy currently has no
support for them, so this pull request implements them.
## Solution
The new `Lightmap` component can be attached to any entity that contains
a `Handle<Mesh>` and a `StandardMaterial`. When present, it will be
applied in the PBR shader. Because multiple lightmaps are frequently
packed into atlases, each lightmap may have its own UV boundaries within
its texture. An `exposure` field is also provided, to control the
brightness of the lightmap.
Note that this PR doesn't provide any way to bake the lightmaps. That
can be done with [The Lightmapper] or another solution, such as Unity's
Bakery.
---
## Changelog
### Added
* A new component, `Lightmap`, is available, for baked global
illumination. If your mesh has a second UV channel (UV1), and you attach
this component to the entity with that mesh, Bevy will apply the texture
referenced in the lightmap.
[The Lightmapper]: https://github.com/Naxela/The_Lightmapper
---------
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
<img width="1920" alt="Screenshot 2023-04-26 at 01 07 34"
src="https://user-images.githubusercontent.com/418473/234467578-0f34187b-5863-4ea1-88e9-7a6bb8ce8da3.png">
This PR adds both diffuse and specular light transmission capabilities
to the `StandardMaterial`, with support for screen space refractions.
This enables realistically representing a wide range of real-world
materials, such as:
- Glass; (Including frosted glass)
- Transparent and translucent plastics;
- Various liquids and gels;
- Gemstones;
- Marble;
- Wax;
- Paper;
- Leaves;
- Porcelain.
Unlike existing support for transparency, light transmission does not
rely on fixed function alpha blending, and therefore works with both
`AlphaMode::Opaque` and `AlphaMode::Mask` materials.
## Solution
- Introduces a number of transmission related fields in the
`StandardMaterial`;
- For specular transmission:
- Adds logic to take a view main texture snapshot after the opaque
phase; (in order to perform screen space refractions)
- Introduces a new `Transmissive3d` phase to the renderer, to which all
meshes with `transmission > 0.0` materials are sent.
- Calculates a light exit point (of the approximate mesh volume) using
`ior` and `thickness` properties
- Samples the snapshot texture with an adaptive number of taps across a
`roughness`-controlled radius enabling “blurry” refractions
- For diffuse transmission:
- Approximates transmitted diffuse light by using a second, flipped +
displaced, diffuse-only Lambertian lobe for each light source.
## To Do
- [x] Figure out where `fresnel_mix()` is taking place, if at all, and
where `dielectric_specular` is being calculated, if at all, and update
them to use the `ior` value (Not a blocker, just a nice-to-have for more
correct BSDF)
- To the _best of my knowledge, this is now taking place, after
964340cdd. The fresnel mix is actually "split" into two parts in our
implementation, one `(1 - fresnel(...))` in the transmission, and
`fresnel()` in the light implementations. A surface with more
reflectance now will produce slightly dimmer transmission towards the
grazing angle, as more of the light gets reflected.
- [x] Add `transmission_texture`
- [x] Add `diffuse_transmission_texture`
- [x] Add `thickness_texture`
- [x] Add `attenuation_distance` and `attenuation_color`
- [x] Connect values to glTF loader
- [x] `transmission` and `transmission_texture`
- [x] `thickness` and `thickness_texture`
- [x] `ior`
- [ ] `diffuse_transmission` and `diffuse_transmission_texture` (needs
upstream support in `gltf` crate, not a blocker)
- [x] Add support for multiple screen space refraction “steps”
- [x] Conditionally create no transmission snapshot texture at all if
`steps == 0`
- [x] Conditionally enable/disable screen space refraction transmission
snapshots
- [x] Read from depth pre-pass to prevent refracting pixels in front of
the light exit point
- [x] Use `interleaved_gradient_noise()` function for sampling blur in a
way that benefits from TAA
- [x] Drill down a TAA `#define`, tweak some aspects of the effect
conditionally based on it
- [x] Remove const array that's crashing under HLSL (unless a new `naga`
release with https://github.com/gfx-rs/naga/pull/2496 comes out before
we merge this)
- [ ] Look into alternatives to the `switch` hack for dynamically
indexing the const array (might not be needed, compilers seem to be
decent at expanding it)
- [ ] Add pipeline keys for gating transmission (do we really want/need
this?)
- [x] Tweak some material field/function names?
## A Note on Texture Packing
_This was originally added as a comment to the
`specular_transmission_texture`, `thickness_texture` and
`diffuse_transmission_texture` documentation, I removed it since it was
more confusing than helpful, and will likely be made redundant/will need
to be updated once we have a better infrastructure for preprocessing
assets_
Due to how channels are mapped, you can more efficiently use a single
shared texture image
for configuring the following:
- R - `specular_transmission_texture`
- G - `thickness_texture`
- B - _unused_
- A - `diffuse_transmission_texture`
The `KHR_materials_diffuse_transmission` glTF extension also defines a
`diffuseTransmissionColorTexture`,
that _we don't currently support_. One might choose to pack the
intensity and color textures together,
using RGB for the color and A for the intensity, in which case this
packing advice doesn't really apply.
---
## Changelog
- Added a new `Transmissive3d` render phase for rendering specular
transmissive materials with screen space refractions
- Added rendering support for transmitted environment map light on the
`StandardMaterial` as a fallback for screen space refractions
- Added `diffuse_transmission`, `specular_transmission`, `thickness`,
`ior`, `attenuation_distance` and `attenuation_color` to the
`StandardMaterial`
- Added `diffuse_transmission_texture`, `specular_transmission_texture`,
`thickness_texture` to the `StandardMaterial`, gated behind a new
`pbr_transmission_textures` cargo feature (off by default, for maximum
hardware compatibility)
- Added `Camera3d::screen_space_specular_transmission_steps` for
controlling the number of “layers of transparency” rendered for
transmissive objects
- Added a `TransmittedShadowReceiver` component for enabling shadows in
(diffusely) transmitted light. (disabled by default, as it requires
carefully setting up the `thickness` to avoid self-shadow artifacts)
- Added support for the `KHR_materials_transmission`,
`KHR_materials_ior` and `KHR_materials_volume` glTF extensions
- Renamed items related to temporal jitter for greater consistency
## Migration Guide
- `SsaoPipelineKey::temporal_noise` has been renamed to
`SsaoPipelineKey::temporal_jitter`
- The `TAA` shader def (controlled by the presence of the
`TemporalAntiAliasSettings` component in the camera) has been replaced
with the `TEMPORAL_JITTER` shader def (controlled by the presence of the
`TemporalJitter` component in the camera)
- `MeshPipelineKey::TAA` has been replaced by
`MeshPipelineKey::TEMPORAL_JITTER`
- The `TEMPORAL_NOISE` shader def has been consolidated with
`TEMPORAL_JITTER`
# Objective
Right now, we flip the `world_normal` in response to `double_sided &&
!is_front`, however when calculating `N` from tangents and the normal
map, we don't flip the normal read from the normal map, which produces
extremely weird results.
## Solution
- Pass `double_sided` and `is_front` flags to the
`apply_normal_mapping()` function and use them to conditionally flip
`Nt`
## Comparison
Note: These are from a custom scene running with the `transmission`
branch, (#8015) I noticed lighting got pretty weird for the back side of
translucent `double_sided` materials whenever I added a normal map.
### Before
<img width="1392" alt="Screenshot 2023-10-31 at 01 26 06"
src="https://github.com/bevyengine/bevy/assets/418473/d5f8c9c3-aca1-4c2f-854d-f0d0fd2fb19a">
### After
<img width="1392" alt="Screenshot 2023-10-31 at 01 25 42"
src="https://github.com/bevyengine/bevy/assets/418473/fa0e1aa2-19ad-4c27-bb08-37299d97971c">
---
## Changelog
- Fixed a bug where `StandardMaterial::double_sided` would interact
incorrectly with normal maps, producing broken results.
# Objective
- bump naga_oil to 0.10
- update shader imports to use rusty syntax
## Migration Guide
naga_oil 0.10 reworks the import mechanism to support more syntax to
make it more rusty, and test for item use before importing to determine
which imports are modules and which are items, which allows:
- use rust-style imports
```
#import bevy_pbr::{
pbr_functions::{alpha_discard as discard, apply_pbr_lighting},
mesh_bindings,
}
```
- import partial paths:
```
#import part::of::path
...
path::remainder::function();
```
which will call to `part::of::path::remainder::function`
- use fully qualified paths without importing:
```
// #import bevy_pbr::pbr_functions
bevy_pbr::pbr_functions::pbr()
```
- use imported items without qualifying
```
#import bevy_pbr::pbr_functions::pbr
// for backwards compatibility the old style is still supported:
// #import bevy_pbr::pbr_functions pbr
...
pbr()
```
- allows most imported items to end with `_` and numbers (naga_oil#30).
still doesn't allow struct members to end with `_` or numbers but it's
progress.
- the vast majority of existing shader code will work without changes,
but will emit "deprecated" warnings for old-style imports. these can be
suppressed with the `allow-deprecated` feature.
- partly breaks overrides (as far as i'm aware nobody uses these yet) -
now overrides will only be applied if the overriding module is added as
an additional import in the arguments to `Composer::make_naga_module` or
`Composer::add_composable_module`. this is necessary to support
determining whether imports are modules or items.
# Objective
allow extending `Material`s (including the built in `StandardMaterial`)
with custom vertex/fragment shaders and additional data, to easily get
pbr lighting with custom modifications, or otherwise extend a base
material.
# Solution
- added `ExtendedMaterial<B: Material, E: MaterialExtension>` which
contains a base material and a user-defined extension.
- added example `extended_material` showing how to use it
- modified AsBindGroup to have "unprepared" functions that return raw
resources / layout entries so that the extended material can combine
them
note: doesn't currently work with array resources, as i can't figure out
how to make the OwnedBindingResource::get_binding() work, as wgpu
requires a `&'a[&'a TextureView]` and i have a `Vec<TextureView>`.
# Migration Guide
manual implementations of `AsBindGroup` will need to be adjusted, the
changes are pretty straightforward and can be seen in the diff for e.g.
the `texture_binding_array` example.
---------
Co-authored-by: Robert Swain <robert.swain@gmail.com>
