Add Mesh transformation

crates/bevy_render/src/mesh/mesh/mod.rs

@@ -1,5 +1,6 @@
 mod conversions;
 pub mod skinning;
+use bevy_transform::components::Transform;
 pub use wgpu::PrimitiveTopology;
 
 use crate::{
@@ -572,6 +573,36 @@ impl Mesh {
         Ok(self)
     }
 
+    /// Transforms the vertex positions, normals, and tangents of the mesh by the given [`Transform`].
+    pub fn transform_by(&mut self, transform: Transform) {
+        if let Some(VertexAttributeValues::Float32x3(ref mut positions)) =
+            self.attribute_mut(Mesh::ATTRIBUTE_POSITION)
+        {
+            // Apply scale, rotation, and translation to vertex positions
+            positions
+                .iter_mut()
+                .for_each(|pos| *pos = transform.transform_point(Vec3::from_slice(pos)).to_array());
+        }
+
+        if let Some(VertexAttributeValues::Float32x3(ref mut normals)) =
+            self.attribute_mut(Mesh::ATTRIBUTE_NORMAL)
+        {
+            // Rotate normals by transform rotation
+            normals.iter_mut().for_each(|normal| {
+                *normal = (transform.rotation * Vec3::from_slice(normal)).to_array();
+            });
+        }
+
+        if let Some(VertexAttributeValues::Float32x3(ref mut tangents)) =
+            self.attribute_mut(Mesh::ATTRIBUTE_TANGENT)
+        {
+            // Rotate tangents by transform rotation
+            tangents.iter_mut().for_each(|tangent| {
+                *tangent = (transform.rotation * Vec3::from_slice(tangent)).to_array();
+            });
+        }
+    }
+
     /// Compute the Axis-Aligned Bounding Box of the mesh vertices in model space
     ///
     /// Returns `None` if `self` doesn't have [`Mesh::ATTRIBUTE_POSITION`] of