Add Mul operator for Quaternion + Vector3.

godot-core/src/builtin/quaternion.rs

@@ -281,6 +281,15 @@ impl Mul<Quaternion> for Quaternion {
     }
 }
 
+impl Mul<Vector3> for Quaternion {
+    type Output = Vector3;
+
+    fn mul(self, rhs: Vector3) -> Self::Output {
+        // TODO: should we panic if this quaternion is not normalized
+        Vector3::from_glam(self.to_glam().mul_vec3(rhs.to_glam()))
+    }
+}
+
 // SAFETY:
 // This type is represented as `Self` in Godot, so `*mut Self` is sound.
 unsafe impl GodotFfi for Quaternion {

godot-core/src/builtin/vectors/vector_macros.rs

@@ -419,14 +419,14 @@ macro_rules! impl_vector_fns {
             }
 
             /// Converts the corresponding `glam` type to `Self`.
-            fn from_glam(v: $GlamVector) -> Self {
+            pub(crate) fn from_glam(v: $GlamVector) -> Self {
                 Self::new(
                     $( v.$comp ),*
                 )
             }
 
             /// Converts `self` to the corresponding `glam` type.
-            fn to_glam(self) -> $GlamVector {
+            pub(crate) fn to_glam(self) -> $GlamVector {
                 <$GlamVector>::new(
                     $( self.$comp ),*
                 )

itest/rust/src/builtin_tests/geometry/quaternion_test.rs

@@ -178,4 +178,28 @@ fn quaternion_spherical_cubic_interpolate_in_time() {
     );
     assert_eq!(outcome, Quaternion::default())
 }
+
+#[itest]
+fn quaternion_mul1() {
+    use std::f32::consts::PI;
+    use godot::builtin::real;
+
+    let q = Quaternion::from_axis_angle(Vector3::UP, PI / 2.0 as real);
+    let rotated = q * Vector3::new(1.0, 4.2, 0.0);
+    assert_eq_approx!(rotated.x, 0.0);
+    assert_eq_approx!(rotated.y, 4.2);
+    assert_eq_approx!(rotated.z, -1.0);
+}
+
+#[itest]
+fn quaternion_mul2() {
+    use std::f32::consts::PI;
+    use godot::builtin::real;
+
+    let q = Quaternion::from_axis_angle(-Vector3::UP, PI / 2.0 as real);
+    let rotated = q * Vector3::new(1.0, 4.2, 2.0);
+    assert_eq_approx!(rotated.x, -2.0);
+    assert_eq_approx!(rotated.y, 4.2);
+    assert_eq_approx!(rotated.z, 1.0);
+}
 // TODO more tests