Add helpers for translate, rotate, and scale operations - Mesh

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

@@ -613,6 +613,120 @@ impl Mesh {
  }
  }
 
+ /// Translates the vertex positions of the mesh by the given [`Vec3`].
+ pub fn translated_by(mut self, translation: Vec3) -> Self {
+ self.translate_by(translation);
+ self
+ }
+
+ /// Translates the vertex positions of the mesh in place by the given [`Vec3`].
+ pub fn translate_by(&mut self, translation: Vec3) {
+ if translation == Vec3::ZERO {
+ return;
+ }
+
+ if let Some(VertexAttributeValues::Float32x3(ref mut positions)) =
+ self.attribute_mut(Mesh::ATTRIBUTE_POSITION)
+ {
+ // Apply translation to vertex positions
+ positions
+ .iter_mut()
+ .for_each(|pos| *pos = (Vec3::from_slice(pos) + translation).to_array());
+ }
+ }
+
+ /// Rotates the vertex positions, normals, and tangents of the mesh by the given [`Quat`].
+ pub fn rotated_by(mut self, rotation: Quat) -> Self {
+ self.rotate_by(rotation);
+ self
+ }
+
+ /// Rotates the vertex positions, normals, and tangents of the mesh in place by the given [`Quat`].
+ pub fn rotate_by(&mut self, rotation: Quat) {
+ if let Some(VertexAttributeValues::Float32x3(ref mut positions)) =
+ self.attribute_mut(Mesh::ATTRIBUTE_POSITION)
+ {
+ // Apply rotation to vertex positions
+ positions
+ .iter_mut()
+ .for_each(|pos| *pos = (rotation * Vec3::from_slice(pos)).to_array());
+ }
+
+ // No need to transform normals or tangents if rotation is near identity
+ if rotation.is_near_identity() {
+ return;
+ }
+
+ if let Some(VertexAttributeValues::Float32x3(ref mut normals)) =
+ self.attribute_mut(Mesh::ATTRIBUTE_NORMAL)
+ {
+ // Transform normals
+ normals.iter_mut().for_each(|normal| {
+ *normal = (rotation * Vec3::from_slice(normal).normalize_or_zero()).to_array();
+ });
+ }
+
+ if let Some(VertexAttributeValues::Float32x3(ref mut tangents)) =
+ self.attribute_mut(Mesh::ATTRIBUTE_TANGENT)
+ {
+ // Transform tangents
+ tangents.iter_mut().for_each(|tangent| {
+ *tangent = (rotation * Vec3::from_slice(tangent).normalize_or_zero()).to_array();
+ });
+ }
+ }
+
+ /// Scales the vertex positions, normals, and tangents of the mesh by the given [`Vec3`].
+ pub fn scaled_by(mut self, scale: Vec3) -> Self {
+ self.scale_by(scale);
+ self
+ }
+
+ /// Scales the vertex positions, normals, and tangents of the mesh in place by the given [`Vec3`].
+ pub fn scale_by(&mut self, scale: Vec3) {
+ // Needed when transforming normals and tangents
+ let covector_scale = scale.yzx() * scale.zxy();
+
+ debug_assert!(
+ covector_scale != Vec3::ZERO,
+ "mesh transform scale cannot be zero on more than one axis"
+ );
+
+ if let Some(VertexAttributeValues::Float32x3(ref mut positions)) =
+ self.attribute_mut(Mesh::ATTRIBUTE_POSITION)
+ {
+ // Apply scale to vertex positions
+ positions
+ .iter_mut()
+ .for_each(|pos| *pos = (scale * Vec3::from_slice(pos)).to_array());
+ }
+
+ // No need to transform normals or tangents if scale is uniform
+ if scale.x == scale.y && scale.y == scale.z {
+ return;
+ }
+
+ if let Some(VertexAttributeValues::Float32x3(ref mut normals)) =
+ self.attribute_mut(Mesh::ATTRIBUTE_NORMAL)
+ {
+ // Transform normals, taking into account non-uniform scaling
+ normals.iter_mut().for_each(|normal| {
+ let scaled_normal = Vec3::from_slice(normal) * covector_scale;
+ *normal = scaled_normal.normalize_or_zero().to_array();
+ });
+ }
+
+ if let Some(VertexAttributeValues::Float32x3(ref mut tangents)) =
+ self.attribute_mut(Mesh::ATTRIBUTE_TANGENT)
+ {
+ // Transform tangents, taking into account non-uniform scaling
+ tangents.iter_mut().for_each(|tangent| {
+ let scaled_tangent = Vec3::from_slice(tangent) * covector_scale;
+ *tangent = scaled_tangent.normalize_or_zero().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