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Author	SHA1	Message	Date
Patrick Walton	b7bcd313ca	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>	2024-12-05 13:07:10 +00:00
Ricky Taylor	9b9d3d81cb	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`.	2024-06-03 16:56:53 +00:00
Patrick Walton	4c15dd0fc5	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.	2024-02-06 23:23:20 +00:00

Author

SHA1

Message

Date

Patrick Walton

b7bcd313ca

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>

2024-12-05 13:07:10 +00:00

Ricky Taylor

9b9d3d81cb

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`.

2024-06-03 16:56:53 +00:00

Patrick Walton

4c15dd0fc5

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.

2024-02-06 23:23:20 +00:00

3 commits