bevy_mesh optional morph (#21389)

# Objective

- make morph support optional on bevy_mesh
- unblock #20742
- another step towards #20867

## Solution

- feature

## Testing

- morph targets example works

Cargo.toml

@@ -166,6 +166,7 @@ default = [
   "default_font",
   "hdr",
   "ktx2",
+  "morph",
   "multi_threaded",
   "png",
   "reflect_auto_register",
@@ -441,6 +442,9 @@ bevy_ci_testing = ["bevy_internal/bevy_ci_testing"]
 # Enable animation support, and glTF animation loading
 animation = ["bevy_internal/animation", "bevy_animation"]
 
+# Enables support for morph target weights in bevy_mesh
+morph = ["bevy_internal/morph"]
+
 # Enable using a shared stdlib for cxx on Android
 android_shared_stdcxx = ["bevy_internal/android_shared_stdcxx"]
 

crates/bevy_animation/Cargo.toml

@@ -16,7 +16,9 @@ bevy_asset = { path = "../bevy_asset", version = "0.18.0-dev" }
 bevy_color = { path = "../bevy_color", version = "0.18.0-dev" }
 bevy_derive = { path = "../bevy_derive", version = "0.18.0-dev" }
 bevy_math = { path = "../bevy_math", version = "0.18.0-dev" }
-bevy_mesh = { path = "../bevy_mesh", version = "0.18.0-dev" }
+bevy_mesh = { path = "../bevy_mesh", version = "0.18.0-dev", features = [
+  "morph",
+] }
 bevy_reflect = { path = "../bevy_reflect", version = "0.18.0-dev", features = [
   "petgraph",
 ] }

crates/bevy_internal/Cargo.toml

@@ -209,6 +209,9 @@ animation = [
   "bevy_gltf?/bevy_animation",
 ]
 
+# Enables support for morph target weights in bevy_mesh
+morph = ["bevy_mesh?/morph", "bevy_render?/morph"]
+
 bevy_shader = ["dep:bevy_shader"]
 bevy_image = ["dep:bevy_image", "bevy_color", "bevy_asset"]
 bevy_sprite = ["dep:bevy_sprite", "bevy_camera"]

crates/bevy_mesh/Cargo.toml

@@ -12,7 +12,7 @@ keywords = ["bevy"]
 # bevy
 bevy_app = { path = "../bevy_app", version = "0.18.0-dev" }
 bevy_asset = { path = "../bevy_asset", version = "0.18.0-dev" }
-bevy_image = { path = "../bevy_image", version = "0.18.0-dev" }
+bevy_image = { path = "../bevy_image", version = "0.18.0-dev", optional = true }
 bevy_math = { path = "../bevy_math", version = "0.18.0-dev" }
 bevy_reflect = { path = "../bevy_reflect", version = "0.18.0-dev" }
 bevy_ecs = { path = "../bevy_ecs", version = "0.18.0-dev" }
@@ -43,6 +43,7 @@ serde_json = "1.0.140"
 default = []
 ## Adds serialization support through `serde`.
 serialize = ["dep:serde", "wgpu-types/serde"]
+morph = ["dep:bevy_image"]
 
 [lints]
 workspace = true

crates/bevy_mesh/src/lib.rs

@@ -8,6 +8,7 @@ mod conversions;
 mod index;
 mod mesh;
 mod mikktspace;
+#[cfg(feature = "morph")]
 pub mod morph;
 pub mod primitives;
 pub mod skinning;
@@ -28,10 +29,10 @@ pub use wgpu_types::VertexFormat;
 ///
 /// This includes the most common types in this crate, re-exported for your convenience.
 pub mod prelude {
+    #[cfg(feature = "morph")]
+    pub use crate::morph::MorphWeights;
     #[doc(hidden)]
-    pub use crate::{
-        morph::MorphWeights, primitives::MeshBuilder, primitives::Meshable, Mesh, Mesh2d, Mesh3d,
-    };
+    pub use crate::{primitives::MeshBuilder, primitives::Meshable, Mesh, Mesh2d, Mesh3d};
 }
 
 bitflags! {

crates/bevy_mesh/src/mesh.rs

@@ -10,7 +10,10 @@ use super::{
 #[cfg(feature = "serialize")]
 use crate::SerializedMeshAttributeData;
 use alloc::collections::BTreeMap;
-use bevy_asset::{Asset, Handle, RenderAssetUsages};
+#[cfg(feature = "morph")]
+use bevy_asset::Handle;
+use bevy_asset::{Asset, RenderAssetUsages};
+#[cfg(feature = "morph")]
 use bevy_image::Image;
 use bevy_math::{primitives::Triangle3d, *};
 #[cfg(feature = "serialize")]
@@ -127,7 +130,9 @@ pub struct Mesh {
     #[reflect(ignore, clone)]
     attributes: BTreeMap<MeshVertexAttributeId, MeshAttributeData>,
     indices: Option<Indices>,
+    #[cfg(feature = "morph")]
     morph_targets: Option<Handle<Image>>,
+    #[cfg(feature = "morph")]
     morph_target_names: Option<Vec<String>>,
     pub asset_usage: RenderAssetUsages,
     /// Whether or not to build a BLAS for use with `bevy_solari` raytracing.
@@ -230,7 +235,9 @@ impl Mesh {
             primitive_topology,
             attributes: Default::default(),
             indices: None,
+            #[cfg(feature = "morph")]
             morph_targets: None,
+            #[cfg(feature = "morph")]
             morph_target_names: None,
             asset_usage,
             enable_raytracing: true,
@@ -1231,55 +1238,6 @@ impl Mesh {
         }
     }
 
-    /// Whether this mesh has morph targets.
-    pub fn has_morph_targets(&self) -> bool {
-        self.morph_targets.is_some()
-    }
-
-    /// Set [morph targets] image for this mesh. This requires a "morph target image". See [`MorphTargetImage`](crate::morph::MorphTargetImage) for info.
-    ///
-    /// [morph targets]: https://en.wikipedia.org/wiki/Morph_target_animation
-    pub fn set_morph_targets(&mut self, morph_targets: Handle<Image>) {
-        self.morph_targets = Some(morph_targets);
-    }
-
-    pub fn morph_targets(&self) -> Option<&Handle<Image>> {
-        self.morph_targets.as_ref()
-    }
-
-    /// Consumes the mesh and returns a mesh with the given [morph targets].
-    ///
-    /// This requires a "morph target image". See [`MorphTargetImage`](crate::morph::MorphTargetImage) for info.
-    ///
-    /// (Alternatively, you can use [`Mesh::set_morph_targets`] to mutate an existing mesh in-place)
-    ///
-    /// [morph targets]: https://en.wikipedia.org/wiki/Morph_target_animation
-    #[must_use]
-    pub fn with_morph_targets(mut self, morph_targets: Handle<Image>) -> Self {
-        self.set_morph_targets(morph_targets);
-        self
-    }
-
-    /// Sets the names of each morph target. This should correspond to the order of the morph targets in `set_morph_targets`.
-    pub fn set_morph_target_names(&mut self, names: Vec<String>) {
-        self.morph_target_names = Some(names);
-    }
-
-    /// Consumes the mesh and returns a mesh with morph target names.
-    /// Names should correspond to the order of the morph targets in `set_morph_targets`.
-    ///
-    /// (Alternatively, you can use [`Mesh::set_morph_target_names`] to mutate an existing mesh in-place)
-    #[must_use]
-    pub fn with_morph_target_names(mut self, names: Vec<String>) -> Self {
-        self.set_morph_target_names(names);
-        self
-    }
-
-    /// Gets a list of all morph target names, if they exist.
-    pub fn morph_target_names(&self) -> Option<&[String]> {
-        self.morph_target_names.as_deref()
-    }
-
     /// Normalize joint weights so they sum to 1.
     pub fn normalize_joint_weights(&mut self) {
         if let Some(joints) = self.attribute_mut(Self::ATTRIBUTE_JOINT_WEIGHT) {
@@ -1404,6 +1362,58 @@ impl Mesh {
     }
 }
 
+#[cfg(feature = "morph")]
+impl Mesh {
+    /// Whether this mesh has morph targets.
+    pub fn has_morph_targets(&self) -> bool {
+        self.morph_targets.is_some()
+    }
+
+    /// Set [morph targets] image for this mesh. This requires a "morph target image". See [`MorphTargetImage`](crate::morph::MorphTargetImage) for info.
+    ///
+    /// [morph targets]: https://en.wikipedia.org/wiki/Morph_target_animation
+    pub fn set_morph_targets(&mut self, morph_targets: Handle<Image>) {
+        self.morph_targets = Some(morph_targets);
+    }
+
+    pub fn morph_targets(&self) -> Option<&Handle<Image>> {
+        self.morph_targets.as_ref()
+    }
+
+    /// Consumes the mesh and returns a mesh with the given [morph targets].
+    ///
+    /// This requires a "morph target image". See [`MorphTargetImage`](crate::morph::MorphTargetImage) for info.
+    ///
+    /// (Alternatively, you can use [`Mesh::set_morph_targets`] to mutate an existing mesh in-place)
+    ///
+    /// [morph targets]: https://en.wikipedia.org/wiki/Morph_target_animation
+    #[must_use]
+    pub fn with_morph_targets(mut self, morph_targets: Handle<Image>) -> Self {
+        self.set_morph_targets(morph_targets);
+        self
+    }
+
+    /// Sets the names of each morph target. This should correspond to the order of the morph targets in `set_morph_targets`.
+    pub fn set_morph_target_names(&mut self, names: Vec<String>) {
+        self.morph_target_names = Some(names);
+    }
+
+    /// Consumes the mesh and returns a mesh with morph target names.
+    /// Names should correspond to the order of the morph targets in `set_morph_targets`.
+    ///
+    /// (Alternatively, you can use [`Mesh::set_morph_target_names`] to mutate an existing mesh in-place)
+    #[must_use]
+    pub fn with_morph_target_names(mut self, names: Vec<String>) -> Self {
+        self.set_morph_target_names(names);
+        self
+    }
+
+    /// Gets a list of all morph target names, if they exist.
+    pub fn morph_target_names(&self) -> Option<&[String]> {
+        self.morph_target_names.as_deref()
+    }
+}
+
 impl core::ops::Mul<Mesh> for Transform {
     type Output = Mesh;
 

crates/bevy_render/Cargo.toml

@@ -23,6 +23,8 @@ decoupled_naga = ["bevy_shader/decoupled_naga"]
 
 multi_threaded = ["bevy_tasks/multi_threaded"]
 
+morph = ["bevy_mesh/morph"]
+
 shader_format_spirv = ["bevy_shader/shader_format_spirv", "wgpu/spirv"]
 
 # Enable SPIR-V shader passthrough

crates/bevy_render/src/lib.rs

@@ -79,7 +79,7 @@ pub use extract_param::Extract;
 use crate::{
     camera::CameraPlugin,
     gpu_readback::GpuReadbackPlugin,
-    mesh::{MeshRenderAssetPlugin, MorphPlugin, RenderMesh},
+    mesh::{MeshRenderAssetPlugin, RenderMesh},
     render_asset::prepare_assets,
     render_resource::{init_empty_bind_group_layout, PipelineCache},
     renderer::{render_system, RenderAdapterInfo},
@@ -368,7 +368,8 @@ impl Plugin for RenderPlugin {
             ViewPlugin,
             MeshRenderAssetPlugin,
             GlobalsPlugin,
-            MorphPlugin,
+            #[cfg(feature = "morph")]
+            mesh::MorphPlugin,
             TexturePlugin,
             BatchingPlugin {
                 debug_flags: self.debug_flags,

crates/bevy_render/src/mesh/mod.rs

@@ -1,12 +1,11 @@
 pub mod allocator;
 use crate::{
     render_asset::{PrepareAssetError, RenderAsset, RenderAssetPlugin, RenderAssets},
-    render_resource::TextureView,
     texture::GpuImage,
     RenderApp,
 };
 use allocator::MeshAllocatorPlugin;
-use bevy_app::{App, Plugin, PostUpdate};
+use bevy_app::{App, Plugin};
 use bevy_asset::{AssetId, RenderAssetUsages};
 use bevy_ecs::{
     prelude::*,
@@ -15,6 +14,7 @@ use bevy_ecs::{
         SystemParamItem,
     },
 };
+#[cfg(feature = "morph")]
 use bevy_mesh::morph::{MeshMorphWeights, MorphWeights};
 use bevy_mesh::*;
 use wgpu::IndexFormat;
@@ -40,10 +40,15 @@ impl Plugin for MeshRenderAssetPlugin {
 
 /// [Inherit weights](inherit_weights) from glTF mesh parent entity to direct
 /// bevy mesh child entities (ie: glTF primitive).
+#[cfg(feature = "morph")]
 pub struct MorphPlugin;
+#[cfg(feature = "morph")]
 impl Plugin for MorphPlugin {
     fn build(&self, app: &mut App) {
-        app.add_systems(PostUpdate, inherit_weights.in_set(InheritWeightSystems));
+        app.add_systems(
+            bevy_app::PostUpdate,
+            inherit_weights.in_set(InheritWeightSystems),
+        );
     }
 }
 
@@ -51,6 +56,7 @@ impl Plugin for MorphPlugin {
 /// should be inherited by children meshes.
 ///
 /// Only direct children are updated, to fulfill the expectations of glTF spec.
+#[cfg(feature = "morph")]
 pub fn inherit_weights(
     morph_nodes: Query<(&Children, &MorphWeights), (Without<Mesh3d>, Changed<MorphWeights>)>,
     mut morph_primitives: Query<&mut MeshMorphWeights, With<Mesh3d>>,
@@ -71,7 +77,8 @@ pub struct RenderMesh {
     pub vertex_count: u32,
 
     /// Morph targets for the mesh, if present.
-    pub morph_targets: Option<TextureView>,
+    #[cfg(feature = "morph")]
+    pub morph_targets: Option<crate::render_resource::TextureView>,
 
     /// Information about the mesh data buffers, including whether the mesh uses
     /// indices or not.
@@ -140,12 +147,13 @@ impl RenderAsset for RenderMesh {
     fn prepare_asset(
         mesh: Self::SourceAsset,
         _: AssetId<Self::SourceAsset>,
-        (images, mesh_vertex_buffer_layouts): &mut SystemParamItem<Self::Param>,
+        (_images, mesh_vertex_buffer_layouts): &mut SystemParamItem<Self::Param>,
         _: Option<&Self>,
     ) -> Result<Self, PrepareAssetError<Self::SourceAsset>> {
+        #[cfg(feature = "morph")]
         let morph_targets = match mesh.morph_targets() {
             Some(mt) => {
-                let Some(target_image) = images.get(mt) else {
+                let Some(target_image) = _images.get(mt) else {
                     return Err(PrepareAssetError::RetryNextUpdate(mesh));
                 };
                 Some(target_image.texture_view.clone())
@@ -164,17 +172,20 @@ impl RenderAsset for RenderMesh {
         let mesh_vertex_buffer_layout =
             mesh.get_mesh_vertex_buffer_layout(mesh_vertex_buffer_layouts);
 
-        let mut key_bits = BaseMeshPipelineKey::from_primitive_topology(mesh.primitive_topology());
-        key_bits.set(
-            BaseMeshPipelineKey::MORPH_TARGETS,
-            mesh.morph_targets().is_some(),
-        );
+        let key_bits = BaseMeshPipelineKey::from_primitive_topology(mesh.primitive_topology());
+        #[cfg(feature = "morph")]
+        let key_bits = if mesh.morph_targets().is_some() {
+            key_bits | BaseMeshPipelineKey::MORPH_TARGETS
+        } else {
+            key_bits
+        };
 
         Ok(RenderMesh {
             vertex_count: mesh.count_vertices() as u32,
             buffer_info,
             key_bits,
             layout: mesh_vertex_buffer_layout,
+            #[cfg(feature = "morph")]
             morph_targets,
         })
     }

docs/cargo_features.md

@@ -52,6 +52,7 @@ The default feature set enables most of the expected features of a game engine,
 |default_font|Include a default font, containing only ASCII characters, at the cost of a 20kB binary size increase|
 |hdr|HDR image format support|
 |ktx2|KTX2 compressed texture support|
+|morph|Enables support for morph target weights in bevy_mesh|
 |multi_threaded|Enables multithreaded parallelism in the engine. Disabling it forces all engine tasks to run on a single thread.|
 |png|PNG image format support|
 |reflect_auto_register|Enable automatic reflect registration|