Add options to lower precision/compressed vertex buffer

assets/shaders/custom_stencil.wgsl

@@ -1,4 +1,4 @@
-//! A shader showing how to use the vertex position data to output the 
+//! A shader showing how to use the vertex position data to output the
 //! stencil in the right position
 
 // First we import everything we need from bevy_pbr
@@ -14,7 +14,11 @@ struct Vertex {
     @builtin(instance_index) instance_index: u32,
     // Like we defined for the vertex layout
     // position is at location 0
+#ifdef VERTEX_POSITIONS_COMPRESSED
+    @location(0) position: vec4<f32>,
+#else
     @location(0) position: vec3<f32>,
+#endif
 };
 
 // This is the output of the vertex shader and we also use it as the input for the fragment shader
@@ -29,7 +33,12 @@ fn vertex(vertex: Vertex) -> VertexOutput {
     // This is how bevy computes the world position
     // The vertex.instance_index is very important. Especially if you are using batching and gpu preprocessing
     var world_from_local = mesh_functions::get_world_from_local(vertex.instance_index);
-    out.world_position = mesh_functions::mesh_position_local_to_world(world_from_local, vec4(vertex.position, 1.0));
+#ifdef VERTEX_POSITIONS_COMPRESSED
+    let vertex_position = mesh_functions::decompress_vertex_position(vertex.instance_index, vertex.position);
+#else
+    let vertex_position = vertex.position;
+#endif
+    out.world_position = mesh_functions::mesh_position_local_to_world(world_from_local, vec4(vertex_position, 1.0));
     out.clip_position = position_world_to_clip(out.world_position.xyz);
     return out;
 }

assets/shaders/specialized_mesh_pipeline.wgsl

@@ -14,7 +14,11 @@ struct Vertex {
     @builtin(instance_index) instance_index: u32,
     // Like we defined for the vertex layout
     // position is at location 0
+#ifdef VERTEX_POSITIONS_COMPRESSED
+    @location(0) position: vec4<f32>,
+#else
     @location(0) position: vec3<f32>,
+#endif
     // and color at location 1
     @location(1) color: vec4<f32>,
 };
@@ -32,7 +36,12 @@ fn vertex(vertex: Vertex) -> VertexOutput {
     // This is how bevy computes the world position
     // The vertex.instance_index is very important. Especially if you are using batching and gpu preprocessing
     var world_from_local = mesh_functions::get_world_from_local(vertex.instance_index);
-    out.world_position = mesh_functions::mesh_position_local_to_world(world_from_local, vec4(vertex.position, 1.0));
+#ifdef VERTEX_POSITIONS_COMPRESSED
+    let vertex_position = mesh_functions::decompress_vertex_position(vertex.instance_index, vertex.position);
+#else
+    let vertex_position = vertex.position;
+#endif
+    out.world_position = mesh_functions::mesh_position_local_to_world(world_from_local, vec4(vertex_position, 1.0));
     out.clip_position = position_world_to_clip(out.world_position.xyz);
 
     // We just use the raw vertex color

crates/bevy_gltf/Cargo.toml

@@ -29,7 +29,9 @@ bevy_image = { path = "../bevy_image", version = "0.18.0-dev" }
 bevy_light = { path = "../bevy_light", version = "0.18.0-dev" }
 bevy_camera = { path = "../bevy_camera", 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 = [
+  "serialize",
+] }
 bevy_pbr = { path = "../bevy_pbr", version = "0.18.0-dev" }
 bevy_reflect = { path = "../bevy_reflect", version = "0.18.0-dev" }
 bevy_render = { path = "../bevy_render", version = "0.18.0-dev" }

crates/bevy_gltf/src/loader/mod.rs

@@ -30,7 +30,7 @@ use bevy_math::{Mat4, Vec3};
 use bevy_mesh::{
     morph::{MeshMorphWeights, MorphAttributes, MorphTargetImage, MorphWeights},
     skinning::{SkinnedMesh, SkinnedMeshInverseBindposes},
-    Indices, Mesh, Mesh3d, MeshVertexAttribute, PrimitiveTopology,
+    Indices, Mesh, Mesh3d, MeshAttributeCompressionFlags, MeshVertexAttribute, PrimitiveTopology,
 };
 #[cfg(feature = "pbr_transmission_textures")]
 use bevy_pbr::UvChannel;
@@ -185,6 +185,8 @@ pub struct GltfLoaderSettings {
     ///
     /// Otherwise, nodes will be loaded and retained in RAM/VRAM according to the active flags.
     pub load_meshes: RenderAssetUsages,
+    /// Mesh attribute compression flags for the loaded meshes.
+    pub mesh_attribute_compression: MeshAttributeCompressionFlags,
     /// If empty, the gltf materials will be skipped.
     ///
     /// Otherwise, materials will be loaded and retained in RAM/VRAM according to the active flags.
@@ -232,6 +234,7 @@ impl Default for GltfLoaderSettings {
             default_sampler: None,
             override_sampler: false,
             use_model_forward_direction: None,
+            mesh_attribute_compression: MeshAttributeCompressionFlags::default(),
         }
     }
 }
@@ -678,7 +681,7 @@ impl GltfLoader {
                 let primitive_topology = primitive_topology(primitive.mode())?;
 
                 let mut mesh = Mesh::new(primitive_topology, settings.load_meshes);
-
+                mesh.attribute_compression = settings.mesh_attribute_compression;
                 // Read vertex attributes
                 for (semantic, accessor) in primitive.attributes() {
                     if [Semantic::Joints(0), Semantic::Weights(0)].contains(&semantic) {

crates/bevy_mesh/Cargo.toml

@@ -35,14 +35,15 @@ hexasphere = "16.0"
 thiserror = { version = "2", default-features = false }
 tracing = { version = "0.1", default-features = false, features = ["std"] }
 derive_more = { version = "2", default-features = false, features = ["from"] }
+half = { version = "2.4.1", features = ["bytemuck"] }
 
 [dev-dependencies]
 serde_json = "1.0.140"
 
 [features]
 default = []
 ## Adds serialization support through `serde`.
-serialize = ["dep:serde", "wgpu-types/serde"]
+serialize = ["dep:serde", "wgpu-types/serde", "half/serde"]
 morph = ["dep:bevy_image"]
 
 [lints]