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AnimationPlayer can play unrelated AnimationClips #8357

Closed
nicopap opened this issue Apr 11, 2023 · 0 comments · Fixed by #9407
Closed

AnimationPlayer can play unrelated AnimationClips #8357

nicopap opened this issue Apr 11, 2023 · 0 comments · Fixed by #9407
Labels
A-Animation Make things move and change over time C-Bug An unexpected or incorrect behavior

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@nicopap
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nicopap commented Apr 11, 2023

bevy version: main commit dff071c

What you did

I tried to play a Handle<AnimationClip> which animates X (using entity path) on a AnimationPlayer component of entity Y, and the animation played.

What went wrong

The animation played, when the given animation is not supposed to work with this entity. the issue lies in

fn find_bone(
root: Entity,
path: &EntityPath,
children: &Query<&Children>,
names: &Query<&Name>,
path_cache: &mut Vec<Option<Entity>>,
) -> Option<Entity> {
// PERF: finding the target entity can be optimised
let mut current_entity = root;
path_cache.resize(path.parts.len(), None);
// Ignore the first name, it is the root node which we already have
for (idx, part) in path.parts.iter().enumerate().skip(1) {

The name of the root entity is entirely dismissed.

I have three different animated meshes, each with their own AnimationPlayer component.
I have a collection of Handle<AnimationClip>, each AnimationClip is relevant to a single of three meshes (AnimationClip even contains a path to the animated entities).
I can call AnimationPlayer::play on component of entity 1, with an Handle<AnimationClip> containing an animation for entity 2.
This is wrong, it should be impossible to do that.

Ideal implementation

It is possible to check for compatibility in find_bone, return None and print a warning, but ideally, the AnimationPlayer::play method should be able to fail if given the wrong Handle<AnimationClip>, and users should be given a way to test for animation compatibility. This way, it's actually possible to do something about it.

Additional information

This was found it because using the wrong animation on the wrong entity causes a panic with morph targets.

@nicopap nicopap added C-Bug An unexpected or incorrect behavior A-Animation Make things move and change over time labels Apr 11, 2023
nicopap added a commit to nicopap/bevy that referenced this issue Apr 17, 2023
Objective
---------

- Add morph targets to `bevy_pbr` (closes bevyengine#5756) & load them from glTF
- Supersedes bevyengine#3722
- Fixes bevyengine#6814

[Morph targets][1] (also known as shape interpolation, shape keys, or
blend shapes) allow animating individual vertices with fine grained
controls. This is typically used for facial expressions. By
specifying multiple poses as vertex offset, and providing a set of
weight of each pose, it is possible to define surprisingly realistic
transitions between poses. Blending between multiple poses also allow
composition. Morph targets are part of the [gltf standard][2] and are
a feature of Unity and Unreal, and babylone.js, it is only natural to
implement them in bevy.

Solution
--------

This implementation of morph targets uses a 3d storage texture where
each pixel is a component of an animated attribute. Each layer is a
different target. We use a 2d texture for each target, because the
number of attribute×components×animated vertices is expected to
always exceed the maximum pixel row size limit of webGL2. It copies
fairly closely the way skinning is implemented on the CPU side, while
on the GPU side, the shader morph target implementation is a
relatively trivial detail.

We add an optional `morph_texture` to the `Mesh` struct. The
`morph_texture` is built through a method that accepts an iterator
over attribute buffers.

The `MorphWeights` component, user-accessible, controls the blend of
poses used by mesh instances (so that multiple copy of the same mesh
may have different weights), all the weights are uploaded to a
uniform buffer of 256 `f32`. We limit to 16 poses per mesh, and a
total of 256 poses.

More literature:
* Old babylone.js implementation (vertex attribute-based): https://www.eternalcoding.com/dev-log-1-morph-targets/
* Babylone.js implementation (similar to ours): https://www.youtube.com/watch?v=LBPRmGgU0PE
* GPU gems 3: https://developer.nvidia.com/gpugems/gpugems3/part-i-geometry/chapter-3-directx-10-blend-shapes-breaking-limits
* Development discord thread https://discord.com/channels/691052431525675048/1083325980615114772

https://user-images.githubusercontent.com/26321040/231181046-3bca2ab2-d4d9-472e-8098-639f1871ce2e.mp4

Acknowledgements
---------------

* Thanks to @storytold for sponsoring the feature
* Thanks to @superdump  and @james7132 for guidance and help figuring out stuff

Future work
-----------

- Handling of less and more attributes (eg: animated uv, animated arbitrary attributes)
- Dynamic pose allocation (so that zero-weighted poses aren't uploaded to GPU for example, enables much more total poses)
- Better animation API, see bevyengine#8357

----

Changelog
---------

- Add morph targets to bevy meshes
	- Support up to 64 poses per mesh of individually up to
          116508 vertices, animation currently strictly limited to the
          position, normal and tangent attributes.
	- Load a morph target using `Mesh::set_morph_targets`
- Add `VisitMorphTargets` and `VisitMorphAttributes` traits to
  `bevy_render`, this allows defining morph targets (a fairly complex
  and nested data structure) through iterators (ie: single copy instead
  of passing around buffers), see documentation of those traits for
  details
- Add `MorphWeights` component exported by `bevy_render`
	- `MorphWeights` control mesh's morph target weights,
          blending between various poses defined as morph targets.
	- `MorphWeights` are directly inherited by direct children
          (single level of hierarchy) of an entity. This allows
          controlling several mesh primitives through a unique entity
          _as per GLTF spec_.
- Add `GltfMeshExtras` component to query gltf extras specific to
  meshes of a given node
	- This allows reading morph weight names, see the new
          `scene_viewer` `morph_viewer_plugin.rs` module for details.
- Load morph targets weights and buffers in `bevy_gltf`
- handle morph targets animations in `bevy_animation` (previously, it
  was a `warn!` log)
- Add the `multiple_morph_target_meshes.gltf` asset for morph targets
  testing. Load it with the scene viewer.

Migration Guide
---------------

- (very specialized, unlikely to be touched by 3rd parties)
	- `MeshPipeline` now has a single `mesh_layouts` field rather
          than separate `mesh_layout` and `skinned_mesh_layout` fields.
          You should handle all possible mesh bind group layouts in
          your implementation.
	- You should also handle properly the new `MORPH_TARGETS`
          shader def and mesh pipeline key. A new function is exposed
          to make this easier: `set_mesh_binding_defs` .
	- The `MeshBindGroup` resource doesn't exist anymore. Mesh
          bind groups are computed in `queue_mesh_bind_group` system
          and are available as the field `GpuMesh::bind_group` .

[1]: https://en.wikipedia.org/wiki/Morph_target_animation
[2]: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#morph-targets
nicopap added a commit to nicopap/bevy that referenced this issue Apr 17, 2023
Objective
---------

- Add morph targets to `bevy_pbr` (closes bevyengine#5756) & load them from glTF
- Supersedes bevyengine#3722
- Fixes bevyengine#6814

[Morph targets][1] (also known as shape interpolation, shape keys, or
blend shapes) allow animating individual vertices with fine grained
controls. This is typically used for facial expressions. By
specifying multiple poses as vertex offset, and providing a set of
weight of each pose, it is possible to define surprisingly realistic
transitions between poses. Blending between multiple poses also allow
composition. Morph targets are part of the [gltf standard][2] and are
a feature of Unity and Unreal, and babylone.js, it is only natural to
implement them in bevy.

Solution
--------

This implementation of morph targets uses a 3d storage texture where
each pixel is a component of an animated attribute. Each layer is a
different target. We use a 2d texture for each target, because the
number of attribute×components×animated vertices is expected to
always exceed the maximum pixel row size limit of webGL2. It copies
fairly closely the way skinning is implemented on the CPU side, while
on the GPU side, the shader morph target implementation is a
relatively trivial detail.

We add an optional `morph_texture` to the `Mesh` struct. The
`morph_texture` is built through a method that accepts an iterator
over attribute buffers.

The `MorphWeights` component, user-accessible, controls the blend of
poses used by mesh instances (so that multiple copy of the same mesh
may have different weights), all the weights are uploaded to a
uniform buffer of 256 `f32`. We limit to 16 poses per mesh, and a
total of 256 poses.

More literature:
* Old babylone.js implementation (vertex attribute-based): https://www.eternalcoding.com/dev-log-1-morph-targets/
* Babylone.js implementation (similar to ours): https://www.youtube.com/watch?v=LBPRmGgU0PE
* GPU gems 3: https://developer.nvidia.com/gpugems/gpugems3/part-i-geometry/chapter-3-directx-10-blend-shapes-breaking-limits
* Development discord thread https://discord.com/channels/691052431525675048/1083325980615114772

https://user-images.githubusercontent.com/26321040/231181046-3bca2ab2-d4d9-472e-8098-639f1871ce2e.mp4

Acknowledgements
---------------

* Thanks to @storytold for sponsoring the feature
* Thanks to @superdump  and @james7132 for guidance and help figuring out stuff

Future work
-----------

- Handling of less and more attributes (eg: animated uv, animated arbitrary attributes)
- Dynamic pose allocation (so that zero-weighted poses aren't uploaded to GPU for example, enables much more total poses)
- Better animation API, see bevyengine#8357

----

Changelog
---------

- Add morph targets to bevy meshes
	- Support up to 64 poses per mesh of individually up to
          116508 vertices, animation currently strictly limited to the
          position, normal and tangent attributes.
	- Load a morph target using `Mesh::set_morph_targets`
- Add `VisitMorphTargets` and `VisitMorphAttributes` traits to
  `bevy_render`, this allows defining morph targets (a fairly complex
  and nested data structure) through iterators (ie: single copy instead
  of passing around buffers), see documentation of those traits for
  details
- Add `MorphWeights` component exported by `bevy_render`
	- `MorphWeights` control mesh's morph target weights,
          blending between various poses defined as morph targets.
	- `MorphWeights` are directly inherited by direct children
          (single level of hierarchy) of an entity. This allows
          controlling several mesh primitives through a unique entity
          _as per GLTF spec_.
- Add `GltfMeshExtras` component to query gltf extras specific to
  meshes of a given node
	- This allows reading morph weight names, see the new
          `scene_viewer` `morph_viewer_plugin.rs` module for details.
- Load morph targets weights and buffers in `bevy_gltf`
- handle morph targets animations in `bevy_animation` (previously, it
  was a `warn!` log)
- Add the `multiple_morph_target_meshes.gltf` asset for morph targets
  testing. Load it with the scene viewer.

Migration Guide
---------------

- (very specialized, unlikely to be touched by 3rd parties)
	- `MeshPipeline` now has a single `mesh_layouts` field rather
          than separate `mesh_layout` and `skinned_mesh_layout` fields.
          You should handle all possible mesh bind group layouts in
          your implementation.
	- You should also handle properly the new `MORPH_TARGETS`
          shader def and mesh pipeline key. A new function is exposed
          to make this easier: `set_mesh_binding_defs` .
	- The `MeshBindGroup` resource doesn't exist anymore. Mesh
          bind groups are computed in `queue_mesh_bind_group` system
          and are available as the field `GpuMesh::bind_group` .

[1]: https://en.wikipedia.org/wiki/Morph_target_animation
[2]: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#morph-targets
nicopap added a commit to nicopap/bevy that referenced this issue Apr 18, 2023
Objective
---------

- Add morph targets to `bevy_pbr` (closes bevyengine#5756) & load them from glTF
- Supersedes bevyengine#3722
- Fixes bevyengine#6814

[Morph targets][1] (also known as shape interpolation, shape keys, or
blend shapes) allow animating individual vertices with fine grained
controls. This is typically used for facial expressions. By
specifying multiple poses as vertex offset, and providing a set of
weight of each pose, it is possible to define surprisingly realistic
transitions between poses. Blending between multiple poses also allow
composition. Morph targets are part of the [gltf standard][2] and are
a feature of Unity and Unreal, and babylone.js, it is only natural to
implement them in bevy.

Solution
--------

This implementation of morph targets uses a 3d storage texture where
each pixel is a component of an animated attribute. Each layer is a
different target. We use a 2d texture for each target, because the
number of attribute×components×animated vertices is expected to
always exceed the maximum pixel row size limit of webGL2. It copies
fairly closely the way skinning is implemented on the CPU side, while
on the GPU side, the shader morph target implementation is a
relatively trivial detail.

We add an optional `morph_texture` to the `Mesh` struct. The
`morph_texture` is built through a method that accepts an iterator
over attribute buffers.

The `MorphWeights` component, user-accessible, controls the blend of
poses used by mesh instances (so that multiple copy of the same mesh
may have different weights), all the weights are uploaded to a
uniform buffer of 256 `f32`. We limit to 16 poses per mesh, and a
total of 256 poses.

More literature:
* Old babylone.js implementation (vertex attribute-based): https://www.eternalcoding.com/dev-log-1-morph-targets/
* Babylone.js implementation (similar to ours): https://www.youtube.com/watch?v=LBPRmGgU0PE
* GPU gems 3: https://developer.nvidia.com/gpugems/gpugems3/part-i-geometry/chapter-3-directx-10-blend-shapes-breaking-limits
* Development discord thread https://discord.com/channels/691052431525675048/1083325980615114772

https://user-images.githubusercontent.com/26321040/231181046-3bca2ab2-d4d9-472e-8098-639f1871ce2e.mp4

Acknowledgements
---------------

* Thanks to @storytold for sponsoring the feature
* Thanks to @superdump  and @james7132 for guidance and help figuring out stuff

Future work
-----------

- Handling of less and more attributes (eg: animated uv, animated arbitrary attributes)
- Dynamic pose allocation (so that zero-weighted poses aren't uploaded to GPU for example, enables much more total poses)
- Better animation API, see bevyengine#8357

----

Changelog
---------

- Add morph targets to bevy meshes
	- Support up to 64 poses per mesh of individually up to
          116508 vertices, animation currently strictly limited to the
          position, normal and tangent attributes.
	- Load a morph target using `Mesh::set_morph_targets`
- Add `VisitMorphTargets` and `VisitMorphAttributes` traits to
  `bevy_render`, this allows defining morph targets (a fairly complex
  and nested data structure) through iterators (ie: single copy instead
  of passing around buffers), see documentation of those traits for
  details
- Add `MorphWeights` component exported by `bevy_render`
	- `MorphWeights` control mesh's morph target weights,
          blending between various poses defined as morph targets.
	- `MorphWeights` are directly inherited by direct children
          (single level of hierarchy) of an entity. This allows
          controlling several mesh primitives through a unique entity
          _as per GLTF spec_.
- Add `GltfMeshExtras` component to query gltf extras specific to
  meshes of a given node
	- This allows reading morph weight names, see the new
          `scene_viewer` `morph_viewer_plugin.rs` module for details.
- Load morph targets weights and buffers in `bevy_gltf`
- handle morph targets animations in `bevy_animation` (previously, it
  was a `warn!` log)
- Add the `multiple_morph_target_meshes.gltf` asset for morph targets
  testing. Load it with the scene viewer.

Migration Guide
---------------

- (very specialized, unlikely to be touched by 3rd parties)
	- `MeshPipeline` now has a single `mesh_layouts` field rather
          than separate `mesh_layout` and `skinned_mesh_layout` fields.
          You should handle all possible mesh bind group layouts in
          your implementation.
	- You should also handle properly the new `MORPH_TARGETS`
          shader def and mesh pipeline key. A new function is exposed
          to make this easier: `set_mesh_binding_defs` .
	- The `MeshBindGroup` resource doesn't exist anymore. Mesh
          bind groups are computed in `queue_mesh_bind_group` system
          and are available as the field `GpuMesh::bind_group` .

[1]: https://en.wikipedia.org/wiki/Morph_target_animation
[2]: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#morph-targets
nicopap added a commit to nicopap/bevy that referenced this issue Apr 20, 2023
Objective
---------

- Add morph targets to `bevy_pbr` (closes bevyengine#5756) & load them from glTF
- Supersedes bevyengine#3722
- Fixes bevyengine#6814

[Morph targets][1] (also known as shape interpolation, shape keys, or
blend shapes) allow animating individual vertices with fine grained
controls. This is typically used for facial expressions. By
specifying multiple poses as vertex offset, and providing a set of
weight of each pose, it is possible to define surprisingly realistic
transitions between poses. Blending between multiple poses also allow
composition. Morph targets are part of the [gltf standard][2] and are
a feature of Unity and Unreal, and babylone.js, it is only natural to
implement them in bevy.

Solution
--------

This implementation of morph targets uses a 3d storage texture where
each pixel is a component of an animated attribute. Each layer is a
different target. We use a 2d texture for each target, because the
number of attribute×components×animated vertices is expected to
always exceed the maximum pixel row size limit of webGL2. It copies
fairly closely the way skinning is implemented on the CPU side, while
on the GPU side, the shader morph target implementation is a
relatively trivial detail.

We add an optional `morph_texture` to the `Mesh` struct. The
`morph_texture` is built through a method that accepts an iterator
over attribute buffers.

The `MorphWeights` component, user-accessible, controls the blend of
poses used by mesh instances (so that multiple copy of the same mesh
may have different weights), all the weights are uploaded to a
uniform buffer of 256 `f32`. We limit to 16 poses per mesh, and a
total of 256 poses.

More literature:
* Old babylone.js implementation (vertex attribute-based): https://www.eternalcoding.com/dev-log-1-morph-targets/
* Babylone.js implementation (similar to ours): https://www.youtube.com/watch?v=LBPRmGgU0PE
* GPU gems 3: https://developer.nvidia.com/gpugems/gpugems3/part-i-geometry/chapter-3-directx-10-blend-shapes-breaking-limits
* Development discord thread https://discord.com/channels/691052431525675048/1083325980615114772

https://user-images.githubusercontent.com/26321040/231181046-3bca2ab2-d4d9-472e-8098-639f1871ce2e.mp4

Acknowledgements
---------------

* Thanks to @storytold for sponsoring the feature
* Thanks to @superdump  and @james7132 for guidance and help figuring out stuff

Future work
-----------

- Handling of less and more attributes (eg: animated uv, animated arbitrary attributes)
- Dynamic pose allocation (so that zero-weighted poses aren't uploaded to GPU for example, enables much more total poses)
- Better animation API, see bevyengine#8357

----

Changelog
---------

- Add morph targets to bevy meshes
	- Support up to 64 poses per mesh of individually up to
          116508 vertices, animation currently strictly limited to the
          position, normal and tangent attributes.
	- Load a morph target using `Mesh::set_morph_targets`
- Add `VisitMorphTargets` and `VisitMorphAttributes` traits to
  `bevy_render`, this allows defining morph targets (a fairly complex
  and nested data structure) through iterators (ie: single copy instead
  of passing around buffers), see documentation of those traits for
  details
- Add `MorphWeights` component exported by `bevy_render`
	- `MorphWeights` control mesh's morph target weights,
          blending between various poses defined as morph targets.
	- `MorphWeights` are directly inherited by direct children
          (single level of hierarchy) of an entity. This allows
          controlling several mesh primitives through a unique entity
          _as per GLTF spec_.
- Add `GltfMeshExtras` component to query gltf extras specific to
  meshes of a given node
	- This allows reading morph weight names, see the new
          `scene_viewer` `morph_viewer_plugin.rs` module for details.
- Load morph targets weights and buffers in `bevy_gltf`
- handle morph targets animations in `bevy_animation` (previously, it
  was a `warn!` log)
- Add the `multiple_morph_target_meshes.gltf` asset for morph targets
  testing. Load it with the scene viewer.

Migration Guide
---------------

- (very specialized, unlikely to be touched by 3rd parties)
	- `MeshPipeline` now has a single `mesh_layouts` field rather
          than separate `mesh_layout` and `skinned_mesh_layout` fields.
          You should handle all possible mesh bind group layouts in
          your implementation.
	- You should also handle properly the new `MORPH_TARGETS`
          shader def and mesh pipeline key. A new function is exposed
          to make this easier: `set_mesh_binding_defs` .
	- The `MeshBindGroup` resource doesn't exist anymore. Mesh
          bind groups are computed in `queue_mesh_bind_group` system
          and are available as the field `GpuMesh::bind_group` .

[1]: https://en.wikipedia.org/wiki/Morph_target_animation
[2]: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#morph-targets
nicopap added a commit to nicopap/bevy that referenced this issue Apr 22, 2023
Objective
---------

- Add morph targets to `bevy_pbr` (closes bevyengine#5756) & load them from glTF
- Supersedes bevyengine#3722
- Fixes bevyengine#6814

[Morph targets][1] (also known as shape interpolation, shape keys, or
blend shapes) allow animating individual vertices with fine grained
controls. This is typically used for facial expressions. By
specifying multiple poses as vertex offset, and providing a set of
weight of each pose, it is possible to define surprisingly realistic
transitions between poses. Blending between multiple poses also allow
composition. Morph targets are part of the [gltf standard][2] and are
a feature of Unity and Unreal, and babylone.js, it is only natural to
implement them in bevy.

Solution
--------

This implementation of morph targets uses a 3d storage texture where
each pixel is a component of an animated attribute. Each layer is a
different target. We use a 2d texture for each target, because the
number of attribute×components×animated vertices is expected to
always exceed the maximum pixel row size limit of webGL2. It copies
fairly closely the way skinning is implemented on the CPU side, while
on the GPU side, the shader morph target implementation is a
relatively trivial detail.

We add an optional `morph_texture` to the `Mesh` struct. The
`morph_texture` is built through a method that accepts an iterator
over attribute buffers.

The `MorphWeights` component, user-accessible, controls the blend of
poses used by mesh instances (so that multiple copy of the same mesh
may have different weights), all the weights are uploaded to a
uniform buffer of 256 `f32`. We limit to 16 poses per mesh, and a
total of 256 poses.

More literature:
* Old babylone.js implementation (vertex attribute-based): https://www.eternalcoding.com/dev-log-1-morph-targets/
* Babylone.js implementation (similar to ours): https://www.youtube.com/watch?v=LBPRmGgU0PE
* GPU gems 3: https://developer.nvidia.com/gpugems/gpugems3/part-i-geometry/chapter-3-directx-10-blend-shapes-breaking-limits
* Development discord thread https://discord.com/channels/691052431525675048/1083325980615114772

https://user-images.githubusercontent.com/26321040/231181046-3bca2ab2-d4d9-472e-8098-639f1871ce2e.mp4

Acknowledgements
---------------

* Thanks to @storytold for sponsoring the feature
* Thanks to @superdump  and @james7132 for guidance and help figuring out stuff

Future work
-----------

- Handling of less and more attributes (eg: animated uv, animated arbitrary attributes)
- Dynamic pose allocation (so that zero-weighted poses aren't uploaded to GPU for example, enables much more total poses)
- Better animation API, see bevyengine#8357

----

Changelog
---------

- Add morph targets to bevy meshes
	- Support up to 64 poses per mesh of individually up to
          116508 vertices, animation currently strictly limited to the
          position, normal and tangent attributes.
	- Load a morph target using `Mesh::set_morph_targets`
- Add `VisitMorphTargets` and `VisitMorphAttributes` traits to
  `bevy_render`, this allows defining morph targets (a fairly complex
  and nested data structure) through iterators (ie: single copy instead
  of passing around buffers), see documentation of those traits for
  details
- Add `MorphWeights` component exported by `bevy_render`
	- `MorphWeights` control mesh's morph target weights,
          blending between various poses defined as morph targets.
	- `MorphWeights` are directly inherited by direct children
          (single level of hierarchy) of an entity. This allows
          controlling several mesh primitives through a unique entity
          _as per GLTF spec_.
- Add `GltfMeshExtras` component to query gltf extras specific to
  meshes of a given node
	- This allows reading morph weight names, see the new
          `scene_viewer` `morph_viewer_plugin.rs` module for details.
- Load morph targets weights and buffers in `bevy_gltf`
- handle morph targets animations in `bevy_animation` (previously, it
  was a `warn!` log)
- Add the `multiple_morph_target_meshes.gltf` asset for morph targets
  testing. Load it with the scene viewer.

Migration Guide
---------------

- (very specialized, unlikely to be touched by 3rd parties)
	- `MeshPipeline` now has a single `mesh_layouts` field rather
          than separate `mesh_layout` and `skinned_mesh_layout` fields.
          You should handle all possible mesh bind group layouts in
          your implementation.
	- You should also handle properly the new `MORPH_TARGETS`
          shader def and mesh pipeline key. A new function is exposed
          to make this easier: `set_mesh_binding_defs` .
	- The `MeshBindGroup` resource doesn't exist anymore. Mesh
          bind groups are computed in `queue_mesh_bind_group` system
          and are available as the field `GpuMesh::bind_group` .

[1]: https://en.wikipedia.org/wiki/Morph_target_animation
[2]: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#morph-targets
nicopap added a commit to nicopap/bevy that referenced this issue Apr 24, 2023
Objective
---------

- Add morph targets to `bevy_pbr` (closes bevyengine#5756) & load them from glTF
- Supersedes bevyengine#3722
- Fixes bevyengine#6814

[Morph targets][1] (also known as shape interpolation, shape keys, or
blend shapes) allow animating individual vertices with fine grained
controls. This is typically used for facial expressions. By
specifying multiple poses as vertex offset, and providing a set of
weight of each pose, it is possible to define surprisingly realistic
transitions between poses. Blending between multiple poses also allow
composition. Morph targets are part of the [gltf standard][2] and are
a feature of Unity and Unreal, and babylone.js, it is only natural to
implement them in bevy.

Solution
--------

This implementation of morph targets uses a 3d storage texture where
each pixel is a component of an animated attribute. Each layer is a
different target. We use a 2d texture for each target, because the
number of attribute×components×animated vertices is expected to
always exceed the maximum pixel row size limit of webGL2. It copies
fairly closely the way skinning is implemented on the CPU side, while
on the GPU side, the shader morph target implementation is a
relatively trivial detail.

We add an optional `morph_texture` to the `Mesh` struct. The
`morph_texture` is built through a method that accepts an iterator
over attribute buffers.

The `MorphWeights` component, user-accessible, controls the blend of
poses used by mesh instances (so that multiple copy of the same mesh
may have different weights), all the weights are uploaded to a
uniform buffer of 256 `f32`. We limit to 16 poses per mesh, and a
total of 256 poses.

More literature:
* Old babylone.js implementation (vertex attribute-based): https://www.eternalcoding.com/dev-log-1-morph-targets/
* Babylone.js implementation (similar to ours): https://www.youtube.com/watch?v=LBPRmGgU0PE
* GPU gems 3: https://developer.nvidia.com/gpugems/gpugems3/part-i-geometry/chapter-3-directx-10-blend-shapes-breaking-limits
* Development discord thread https://discord.com/channels/691052431525675048/1083325980615114772

https://user-images.githubusercontent.com/26321040/231181046-3bca2ab2-d4d9-472e-8098-639f1871ce2e.mp4

Acknowledgements
---------------

* Thanks to @storytold for sponsoring the feature
* Thanks to @superdump  and @james7132 for guidance and help figuring out stuff

Future work
-----------

- Handling of less and more attributes (eg: animated uv, animated arbitrary attributes)
- Dynamic pose allocation (so that zero-weighted poses aren't uploaded to GPU for example, enables much more total poses)
- Better animation API, see bevyengine#8357

----

Changelog
---------

- Add morph targets to bevy meshes
	- Support up to 64 poses per mesh of individually up to
          116508 vertices, animation currently strictly limited to the
          position, normal and tangent attributes.
	- Load a morph target using `Mesh::set_morph_targets`
- Add `VisitMorphTargets` and `VisitMorphAttributes` traits to
  `bevy_render`, this allows defining morph targets (a fairly complex
  and nested data structure) through iterators (ie: single copy instead
  of passing around buffers), see documentation of those traits for
  details
- Add `MorphWeights` component exported by `bevy_render`
	- `MorphWeights` control mesh's morph target weights,
          blending between various poses defined as morph targets.
	- `MorphWeights` are directly inherited by direct children
          (single level of hierarchy) of an entity. This allows
          controlling several mesh primitives through a unique entity
          _as per GLTF spec_.
- Add `GltfMeshExtras` component to query gltf extras specific to
  meshes of a given node
	- This allows reading morph weight names, see the new
          `scene_viewer` `morph_viewer_plugin.rs` module for details.
- Load morph targets weights and buffers in `bevy_gltf`
- handle morph targets animations in `bevy_animation` (previously, it
  was a `warn!` log)
- Add the `multiple_morph_target_meshes.gltf` asset for morph targets
  testing. Load it with the scene viewer.

Migration Guide
---------------

- (very specialized, unlikely to be touched by 3rd parties)
	- `MeshPipeline` now has a single `mesh_layouts` field rather
          than separate `mesh_layout` and `skinned_mesh_layout` fields.
          You should handle all possible mesh bind group layouts in
          your implementation.
	- You should also handle properly the new `MORPH_TARGETS`
          shader def and mesh pipeline key. A new function is exposed
          to make this easier: `set_mesh_binding_defs` .
	- The `MeshBindGroup` resource doesn't exist anymore. Mesh
          bind groups are computed in `queue_mesh_bind_group` system
          and are available as the field `GpuMesh::bind_group` .

[1]: https://en.wikipedia.org/wiki/Morph_target_animation
[2]: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#morph-targets
github-merge-queue bot pushed a commit that referenced this issue Jun 22, 2023
# Objective

- Add morph targets to `bevy_pbr` (closes #5756) & load them from glTF
- Supersedes #3722
- Fixes #6814

[Morph targets][1] (also known as shape interpolation, shape keys, or
blend shapes) allow animating individual vertices with fine grained
controls. This is typically used for facial expressions. By specifying
multiple poses as vertex offset, and providing a set of weight of each
pose, it is possible to define surprisingly realistic transitions
between poses. Blending between multiple poses also allow composition.
Morph targets are part of the [gltf standard][2] and are a feature of
Unity and Unreal, and babylone.js, it is only natural to implement them
in bevy.

## Solution

This implementation of morph targets uses a 3d texture where each pixel
is a component of an animated attribute. Each layer is a different
target. We use a 2d texture for each target, because the number of
attribute×components×animated vertices is expected to always exceed the
maximum pixel row size limit of webGL2. It copies fairly closely the way
skinning is implemented on the CPU side, while on the GPU side, the
shader morph target implementation is a relatively trivial detail.

We add an optional `morph_texture` to the `Mesh` struct. The
`morph_texture` is built through a method that accepts an iterator over
attribute buffers.

The `MorphWeights` component, user-accessible, controls the blend of
poses used by mesh instances (so that multiple copy of the same mesh may
have different weights), all the weights are uploaded to a uniform
buffer of 256 `f32`. We limit to 16 poses per mesh, and a total of 256
poses.

More literature:
* Old babylone.js implementation (vertex attribute-based):
https://www.eternalcoding.com/dev-log-1-morph-targets/
* Babylone.js implementation (similar to ours):
https://www.youtube.com/watch?v=LBPRmGgU0PE
* GPU gems 3:
https://developer.nvidia.com/gpugems/gpugems3/part-i-geometry/chapter-3-directx-10-blend-shapes-breaking-limits
* Development discord thread
https://discord.com/channels/691052431525675048/1083325980615114772


https://user-images.githubusercontent.com/26321040/231181046-3bca2ab2-d4d9-472e-8098-639f1871ce2e.mp4


https://github.com/bevyengine/bevy/assets/26321040/d2a0c544-0ef8-45cf-9f99-8c3792f5a258

## Acknowledgements

* Thanks to `storytold` for sponsoring the feature
* Thanks to `superdump` and `james7132` for guidance and help figuring
out stuff

## Future work

- Handling of less and more attributes (eg: animated uv, animated
arbitrary attributes)
- Dynamic pose allocation (so that zero-weighted poses aren't uploaded
to GPU for example, enables much more total poses)
- Better animation API, see #8357

----

## Changelog

- Add morph targets to bevy meshes
- Support up to 64 poses per mesh of individually up to 116508 vertices,
animation currently strictly limited to the position, normal and tangent
attributes.
	- Load a morph target using `Mesh::set_morph_targets` 
- Add `VisitMorphTargets` and `VisitMorphAttributes` traits to
`bevy_render`, this allows defining morph targets (a fairly complex and
nested data structure) through iterators (ie: single copy instead of
passing around buffers), see documentation of those traits for details
- Add `MorphWeights` component exported by `bevy_render`
- `MorphWeights` control mesh's morph target weights, blending between
various poses defined as morph targets.
- `MorphWeights` are directly inherited by direct children (single level
of hierarchy) of an entity. This allows controlling several mesh
primitives through a unique entity _as per GLTF spec_.
- Add `MorphTargetNames` component, naming each indices of loaded morph
targets.
- Load morph targets weights and buffers in `bevy_gltf` 
- handle morph targets animations in `bevy_animation` (previously, it
was a `warn!` log)
- Add the `MorphStressTest.gltf` asset for morph targets testing, taken
from the glTF samples repo, CC0.
- Add morph target manipulation to `scene_viewer`
- Separate the animation code in `scene_viewer` from the rest of the
code, reducing `#[cfg(feature)]` noise
- Add the `morph_targets.rs` example to show off how to manipulate morph
targets, loading `MorpStressTest.gltf`

## Migration Guide

- (very specialized, unlikely to be touched by 3rd parties)
- `MeshPipeline` now has a single `mesh_layouts` field rather than
separate `mesh_layout` and `skinned_mesh_layout` fields. You should
handle all possible mesh bind group layouts in your implementation
- You should also handle properly the new `MORPH_TARGETS` shader def and
mesh pipeline key. A new function is exposed to make this easier:
`setup_moprh_and_skinning_defs`
- The `MeshBindGroup` is now `MeshBindGroups`, cached bind groups are
now accessed through the `get` method.

[1]: https://en.wikipedia.org/wiki/Morph_target_animation
[2]:
https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#morph-targets

---------

Co-authored-by: François <[email protected]>
Co-authored-by: Carter Anderson <[email protected]>
github-merge-queue bot pushed a commit that referenced this issue Aug 28, 2023
# Objective

fixes #8357 

gltf animations can affect multiple "root" nodes (i.e. top level nodes
within a gltf scene).

the current loader adds an AnimationPlayer to each root node which is
affected by any animation. when a clip which affects multiple root nodes
is played on a root node player, the root node name is not checked,
leading to potentially incorrect weights being applied.
also, the `AnimationClip::compatible_with` method will never return true
for those clips, as it checks that all paths start with the root node
name - not all paths start with the same name so it can't return true.

## Solution

- check the first path node name matches the given root
- change compatible_with to return true if `any` match is found

a better alternative would probably be to attach the player to the scene
root instead of the first child, and then walk the full path from there.
this would be breaking (and would stop multiple animations that *don't*
overlap from being played concurrently), but i'm happy to modify to that
if it's preferred.

---------

Co-authored-by: Nicola Papale <[email protected]>
rdrpenguin04 pushed a commit to rdrpenguin04/bevy that referenced this issue Jan 9, 2024
# Objective

fixes bevyengine#8357 

gltf animations can affect multiple "root" nodes (i.e. top level nodes
within a gltf scene).

the current loader adds an AnimationPlayer to each root node which is
affected by any animation. when a clip which affects multiple root nodes
is played on a root node player, the root node name is not checked,
leading to potentially incorrect weights being applied.
also, the `AnimationClip::compatible_with` method will never return true
for those clips, as it checks that all paths start with the root node
name - not all paths start with the same name so it can't return true.

## Solution

- check the first path node name matches the given root
- change compatible_with to return true if `any` match is found

a better alternative would probably be to attach the player to the scene
root instead of the first child, and then walk the full path from there.
this would be breaking (and would stop multiple animations that *don't*
overlap from being played concurrently), but i'm happy to modify to that
if it's preferred.

---------

Co-authored-by: Nicola Papale <[email protected]>
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