0fc670fbd4
4 Commits
| Author | SHA1 | Message | Date | |
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charlotte 🌸
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96dcbc5f8c
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Ugrade to wgpu version 25.0 (#19563)
# Objective Upgrade to `wgpu` version `25.0`. Depends on https://github.com/bevyengine/naga_oil/pull/121 ## Solution ### Problem The biggest issue we face upgrading is the following requirement: > To facilitate this change, there was an additional validation rule put in place: if there is a binding array in a bind group, you may not use dynamic offset buffers or uniform buffers in that bind group. This requirement comes from vulkan rules on UpdateAfterBind descriptors. This is a major difficulty for us, as there are a number of binding arrays that are used in the view bind group. Note, this requirement does not affect merely uniform buffors that use dynamic offset but the use of *any* uniform in a bind group that also has a binding array. ### Attempted fixes The easiest fix would be to change uniforms to be storage buffers whenever binding arrays are in use: ```wgsl #ifdef BINDING_ARRAYS_ARE_USED @group(0) @binding(0) var<uniform> view: View; @group(0) @binding(1) var<uniform> lights: types::Lights; #else @group(0) @binding(0) var<storage> view: array<View>; @group(0) @binding(1) var<storage> lights: array<types::Lights>; #endif ``` This requires passing the view index to the shader so that we know where to index into the buffer: ```wgsl struct PushConstants { view_index: u32, } var<push_constant> push_constants: PushConstants; ``` Using push constants is no problem because binding arrays are only usable on native anyway. However, this greatly complicates the ability to access `view` in shaders. For example: ```wgsl #ifdef BINDING_ARRAYS_ARE_USED mesh_view_bindings::view.view_from_world[0].z #else mesh_view_bindings::view[mesh_view_bindings::view_index].view_from_world[0].z #endif ``` Using this approach would work but would have the effect of polluting our shaders with ifdef spam basically *everywhere*. Why not use a function? Unfortunately, the following is not valid wgsl as it returns a binding directly from a function in the uniform path. ```wgsl fn get_view() -> View { #if BINDING_ARRAYS_ARE_USED let view_index = push_constants.view_index; let view = views[view_index]; #endif return view; } ``` This also poses problems for things like lights where we want to return a ptr to the light data. Returning ptrs from wgsl functions isn't allowed even if both bindings were buffers. The next attempt was to simply use indexed buffers everywhere, in both the binding array and non binding array path. This would be viable if push constants were available everywhere to pass the view index, but unfortunately they are not available on webgpu. This means either passing the view index in a storage buffer (not ideal for such a small amount of state) or using push constants sometimes and uniform buffers only on webgpu. However, this kind of conditional layout infects absolutely everything. Even if we were to accept just using storage buffer for the view index, there's also the additional problem that some dynamic offsets aren't actually per-view but per-use of a setting on a camera, which would require passing that uniform data on *every* camera regardless of whether that rendering feature is being used, which is also gross. As such, although it's gross, the simplest solution just to bump binding arrays into `@group(1)` and all other bindings up one bind group. This should still bring us under the device limit of 4 for most users. ### Next steps / looking towards the future I'd like to avoid needing split our view bind group into multiple parts. In the future, if `wgpu` were to add `@builtin(draw_index)`, we could build a list of draw state in gpu processing and avoid the need for any kind of state change at all (see https://github.com/gfx-rs/wgpu/issues/6823). This would also provide significantly more flexibility to handle things like offsets into other arrays that may not be per-view. ### Testing Tested a number of examples, there are probably more that are still broken. --------- Co-authored-by: François Mockers <mockersf@gmail.com> Co-authored-by: Elabajaba <Elabajaba@users.noreply.github.com> |
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Patrick Walton
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b7bcd313ca
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Cluster light probes using conservative spherical bounds. (#13746)
This commit allows the Bevy renderer to use the clustering infrastructure for light probes (reflection probes and irradiance volumes) on platforms where at least 3 storage buffers are available. On such platforms (the vast majority), we stop performing brute-force searches of light probes for each fragment and instead only search the light probes with bounding spheres that intersect the current cluster. This should dramatically improve scalability of irradiance volumes and reflection probes. The primary platform that doesn't support 3 storage buffers is WebGL 2, and we continue using a brute-force search of light probes on that platform, as the UBO that stores per-cluster indices is too small to fit the light probe counts. Note, however, that that platform also doesn't support bindless textures (indeed, it would be very odd for a platform to support bindless textures but not SSBOs), so we only support one of each type of light probe per drawcall there in the first place. Consequently, this isn't a performance problem, as the search will only have one light probe to consider. (In fact, clustering would probably end up being a performance loss.) Known potential improvements include: 1. We currently cull based on a conservative bounding sphere test and not based on the oriented bounding box (OBB) of the light probe. This is improvable, but in the interests of simplicity, I opted to keep the bounding sphere test for now. The OBB improvement can be a follow-up. 2. This patch doesn't change the fact that each fragment only takes a single light probe into account. Typical light probe implementations detect the case in which multiple light probes cover the current fragment and perform some sort of weighted blend between them. As the light probe fetch function presently returns only a single light probe, implementing that feature would require more code restructuring, so I left it out for now. It can be added as a follow-up. 3. Light probe implementations typically have a falloff range. Although this is a wanted feature in Bevy, this particular commit also doesn't implement that feature, as it's out of scope. 4. This commit doesn't raise the maximum number of light probes past its current value of 8 for each type. This should be addressed later, but would possibly require more bindings on platforms with storage buffers, which would increase this patch's complexity. Even without raising the limit, this patch should constitute a significant performance improvement for scenes that get anywhere close to this limit. In the interest of keeping this patch small, I opted to leave raising the limit to a follow-up. ## Changelog ### Changed * Light probes (reflection probes and irradiance volumes) are now clustered on most platforms, improving performance when many light probes are present. --------- Co-authored-by: Benjamin Brienen <Benjamin.Brienen@outlook.com> Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com> |
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Ricky Taylor
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9b9d3d81cb
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Normalise matrix naming (#13489)
# 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`. |
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Patrick Walton
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4c15dd0fc5
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Implement irradiance volumes. (#10268)
# Objective
Bevy could benefit from *irradiance volumes*, also known as *voxel
global illumination* or simply as light probes (though this term is not
preferred, as multiple techniques can be called light probes).
Irradiance volumes are a form of baked global illumination; they work by
sampling the light at the centers of each voxel within a cuboid. At
runtime, the voxels surrounding the fragment center are sampled and
interpolated to produce indirect diffuse illumination.
## Solution
This is divided into two sections. The first is copied and pasted from
the irradiance volume module documentation and describes the technique.
The second part consists of notes on the implementation.
### Overview
An *irradiance volume* is a cuboid voxel region consisting of
regularly-spaced precomputed samples of diffuse indirect light. They're
ideal if you have a dynamic object such as a character that can move
about
static non-moving geometry such as a level in a game, and you want that
dynamic object to be affected by the light bouncing off that static
geometry.
To use irradiance volumes, you need to precompute, or *bake*, the
indirect
light in your scene. Bevy doesn't currently come with a way to do this.
Fortunately, [Blender] provides a [baking tool] as part of the Eevee
renderer, and its irradiance volumes are compatible with those used by
Bevy.
The [`bevy-baked-gi`] project provides a tool, `export-blender-gi`, that
can
extract the baked irradiance volumes from the Blender `.blend` file and
package them up into a `.ktx2` texture for use by the engine. See the
documentation in the `bevy-baked-gi` project for more details as to this
workflow.
Like all light probes in Bevy, irradiance volumes are 1×1×1 cubes that
can
be arbitrarily scaled, rotated, and positioned in a scene with the
[`bevy_transform::components::Transform`] component. The 3D voxel grid
will
be stretched to fill the interior of the cube, and the illumination from
the
irradiance volume will apply to all fragments within that bounding
region.
Bevy's irradiance volumes are based on Valve's [*ambient cubes*] as used
in
*Half-Life 2* ([Mitchell 2006], slide 27). These encode a single color
of
light from the six 3D cardinal directions and blend the sides together
according to the surface normal.
The primary reason for choosing ambient cubes is to match Blender, so
that
its Eevee renderer can be used for baking. However, they also have some
advantages over the common second-order spherical harmonics approach:
ambient cubes don't suffer from ringing artifacts, they are smaller (6
colors for ambient cubes as opposed to 9 for spherical harmonics), and
evaluation is faster. A smaller basis allows for a denser grid of voxels
with the same storage requirements.
If you wish to use a tool other than `export-blender-gi` to produce the
irradiance volumes, you'll need to pack the irradiance volumes in the
following format. The irradiance volume of resolution *(Rx, Ry, Rz)* is
expected to be a 3D texture of dimensions *(Rx, 2Ry, 3Rz)*. The
unnormalized
texture coordinate *(s, t, p)* of the voxel at coordinate *(x, y, z)*
with
side *S* ∈ *{-X, +X, -Y, +Y, -Z, +Z}* is as follows:
```text
s = x
t = y + ⎰ 0 if S ∈ {-X, -Y, -Z}
⎱ Ry if S ∈ {+X, +Y, +Z}
⎧ 0 if S ∈ {-X, +X}
p = z + ⎨ Rz if S ∈ {-Y, +Y}
⎩ 2Rz if S ∈ {-Z, +Z}
```
Visually, in a left-handed coordinate system with Y up, viewed from the
right, the 3D texture looks like a stacked series of voxel grids, one
for
each cube side, in this order:
| **+X** | **+Y** | **+Z** |
| ------ | ------ | ------ |
| **-X** | **-Y** | **-Z** |
A terminology note: Other engines may refer to irradiance volumes as
*voxel
global illumination*, *VXGI*, or simply as *light probes*. Sometimes
*light
probe* refers to what Bevy calls a reflection probe. In Bevy, *light
probe*
is a generic term that encompasses all cuboid bounding regions that
capture
indirect illumination, whether based on voxels or not.
Note that, if binding arrays aren't supported (e.g. on WebGPU or WebGL
2),
then only the closest irradiance volume to the view will be taken into
account during rendering.
[*ambient cubes*]:
https://advances.realtimerendering.com/s2006/Mitchell-ShadingInValvesSourceEngine.pdf
[Mitchell 2006]:
https://advances.realtimerendering.com/s2006/Mitchell-ShadingInValvesSourceEngine.pdf
[Blender]: http://blender.org/
[baking tool]:
https://docs.blender.org/manual/en/latest/render/eevee/render_settings/indirect_lighting.html
[`bevy-baked-gi`]: https://github.com/pcwalton/bevy-baked-gi
### Implementation notes
This patch generalizes light probes so as to reuse as much code as
possible between irradiance volumes and the existing reflection probes.
This approach was chosen because both techniques share numerous
similarities:
1. Both irradiance volumes and reflection probes are cuboid bounding
regions.
2. Both are responsible for providing baked indirect light.
3. Both techniques involve presenting a variable number of textures to
the shader from which indirect light is sampled. (In the current
implementation, this uses binding arrays.)
4. Both irradiance volumes and reflection probes require gathering and
sorting probes by distance on CPU.
5. Both techniques require the GPU to search through a list of bounding
regions.
6. Both will eventually want to have falloff so that we can smoothly
blend as objects enter and exit the probes' influence ranges. (This is
not implemented yet to keep this patch relatively small and reviewable.)
To do this, we generalize most of the methods in the reflection probes
patch #11366 to be generic over a trait, `LightProbeComponent`. This
trait is implemented by both `EnvironmentMapLight` (for reflection
probes) and `IrradianceVolume` (for irradiance volumes). Using a trait
will allow us to add more types of light probes in the future. In
particular, I highly suspect we will want real-time reflection planes
for mirrors in the future, which can be easily slotted into this
framework.
## Changelog
> This section is optional. If this was a trivial fix, or has no
externally-visible impact, you can delete this section.
### Added
* A new `IrradianceVolume` asset type is available for baked voxelized
light probes. You can bake the global illumination using Blender or
another tool of your choice and use it in Bevy to apply indirect
illumination to dynamic objects.
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