Added multiplying a tuple by a matrix

features/src/matrix.rs

@@ -203,6 +203,19 @@ impl std::ops::Mul<&Tuple> for &Matrix {
 
 }
 
+impl std::ops::Mul<&Matrix> for &Tuple {
+    type Output = Tuple;
+
+    fn mul(self, rhs: &Matrix) -> Tuple {
+        Tuple::new(
+            rhs.calc_val_for_mul_tuple(0, &self),
+            rhs.calc_val_for_mul_tuple(1, &self),
+            rhs.calc_val_for_mul_tuple(2, &self),
+            rhs.calc_val_for_mul_tuple(3, &self),
+        )
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -356,6 +369,22 @@ mod tests {
         assert_eq!(&matrix * &tuple, expected);
     }
 
+
+    #[test]
+    fn multiply_by_tuple_reverse() {
+        let matrix = Matrix::from_array([
+            [1.0, 2.0, 3.0, 4.0],
+            [2.0, 4.0, 4.0, 2.0],
+            [8.0, 6.0, 4.0, 1.0],
+            [0.0, 0.0, 0.0, 1.0],
+        ]);
+
+        let tuple = Tuple::new(1.0, 2.0, 3.0, 1.0);
+        let expected = Tuple::new(18.0, 24.0, 33.0, 1.0);
+
+        assert_eq!(&tuple * &matrix, expected);
+    }
+
     #[test]
     fn matrix_by_identity() {
         let matrix = Matrix::from_array([

features/src/transformations.rs

@@ -25,7 +25,7 @@ mod tests {
 
         let expected_point = Tuple::point(2.0, 1.0, 7.0);
 
-        let translated_point = &transform * &p;
+        let translated_point =  &p * &transform;
 
         assert_eq!(expected_point, translated_point);
     }