From 3febc46d5a3426d28d82b768d6d264c1f3492c5b Mon Sep 17 00:00:00 2001
From: Cameron Hart <cam@bitshifter.net.nz>
Date: Sat, 2 Jan 2016 10:14:47 +1100
Subject: [PATCH] Added scalar arithmetic operators for Point types

---
 src/point.rs   | 27 +++++++++++++++++++++++++
 tests/point.rs | 53 +++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 79 insertions(+), 1 deletion(-)

diff --git a/src/point.rs b/src/point.rs
index 362f1b8..33dfc14 100644
--- a/src/point.rs
+++ b/src/point.rs
@@ -172,6 +172,19 @@ macro_rules! impl_point {
             fn rem_assign(&mut self, scalar) { $(self.$field %= scalar);+ }
         });
 
+        impl_scalar_ops!($PointN<usize> { $($field),+ });
+        impl_scalar_ops!($PointN<u8> { $($field),+ });
+        impl_scalar_ops!($PointN<u16> { $($field),+ });
+        impl_scalar_ops!($PointN<u32> { $($field),+ });
+        impl_scalar_ops!($PointN<u64> { $($field),+ });
+        impl_scalar_ops!($PointN<isize> { $($field),+ });
+        impl_scalar_ops!($PointN<i8> { $($field),+ });
+        impl_scalar_ops!($PointN<i16> { $($field),+ });
+        impl_scalar_ops!($PointN<i32> { $($field),+ });
+        impl_scalar_ops!($PointN<i64> { $($field),+ });
+        impl_scalar_ops!($PointN<f32> { $($field),+ });
+        impl_scalar_ops!($PointN<f64> { $($field),+ });
+
         impl_index_operators!($PointN<S>, $n, S, usize);
         impl_index_operators!($PointN<S>, $n, [S], Range<usize>);
         impl_index_operators!($PointN<S>, $n, [S], RangeTo<usize>);
@@ -180,6 +193,20 @@ macro_rules! impl_point {
     }
 }
 
+macro_rules! impl_scalar_ops {
+    ($PointN:ident<$S:ident> { $($field:ident),+ }) => {
+        impl_operator!(Mul<$PointN<$S>> for $S {
+            fn mul(scalar, vector) -> $PointN<$S> { $PointN::new($(scalar * vector.$field),+) }
+        });
+        impl_operator!(Div<$PointN<$S>> for $S {
+            fn div(scalar, vector) -> $PointN<$S> { $PointN::new($(scalar / vector.$field),+) }
+        });
+        impl_operator!(Rem<$PointN<$S>> for $S {
+            fn rem(scalar, vector) -> $PointN<$S> { $PointN::new($(scalar % vector.$field),+) }
+        });
+    };
+}
+
 impl_point!(Point2 { x, y }, Vector2, 2);
 impl_point!(Point3 { x, y, z }, Vector3, 3);
 
diff --git a/tests/point.rs b/tests/point.rs
index 3dbfef6..fcd2714 100644
--- a/tests/point.rs
+++ b/tests/point.rs
@@ -16,11 +16,62 @@
 
 extern crate cgmath;
 
-use cgmath::Point3;
+use cgmath::{Point2, Point3};
 use cgmath::ApproxEq;
 
+macro_rules! impl_test_mul {
+    ($PointN:ident { $($field:ident),+ }, $s:expr, $v:expr) => (
+        // point * scalar ops
+        assert_eq!($v * $s, $PointN::new($($v.$field * $s),+));
+        assert_eq!($s * $v, $PointN::new($($s * $v.$field),+));
+        assert_eq!(&$v * $s, $v * $s);
+        assert_eq!($s * &$v, $s * $v);
+        // commutativity
+        assert_eq!($v * $s, $s * $v);
+    )
+}
+
+macro_rules! impl_test_div {
+    ($PointN:ident { $($field:ident),+ }, $s:expr, $v:expr) => (
+        // point / scalar ops
+        assert_eq!($v / $s, $PointN::new($($v.$field / $s),+));
+        assert_eq!($s / $v, $PointN::new($($s / $v.$field),+));
+        assert_eq!(&$v / $s, $v / $s);
+        assert_eq!($s / &$v, $s / $v);
+    )
+}
+
+macro_rules! impl_test_rem {
+    ($PointN:ident { $($field:ident),+ }, $s:expr, $v:expr) => (
+        // point % scalar ops
+        assert_eq!($v % $s, $PointN::new($($v.$field % $s),+));
+        assert_eq!($s % $v, $PointN::new($($s % $v.$field),+));
+        assert_eq!(&$v % $s, $v % $s);
+        assert_eq!($s % &$v, $s % $v);
+    )
+}
+
 #[test]
 fn test_homogeneous() {
 	let p = Point3::new(1.0f64, 2.0f64, 3.0f64);
     assert!(p.approx_eq(&Point3::from_homogeneous(p.to_homogeneous())));
 }
+
+#[test]
+fn test_mul() {
+    impl_test_mul!(Point3 { x, y, z }, 2.0f32, Point3::new(2.0f32, 4.0, 6.0));
+    impl_test_mul!(Point2 { x, y }, 2.0f32, Point2::new(2.0f32, 4.0));
+}
+
+#[test]
+fn test_div() {
+    impl_test_div!(Point3 { x, y, z }, 2.0f32, Point3::new(2.0f32, 4.0, 6.0));
+    impl_test_div!(Point2 { x, y }, 2.0f32, Point2::new(2.0f32, 4.0));
+}
+
+#[test]
+fn test_rem() {
+    impl_test_rem!(Point3 { x, y, z }, 2.0f32, Point3::new(2.0f32, 4.0, 6.0));
+    impl_test_rem!(Point2 { x, y }, 2.0f32, Point2::new(2.0f32, 4.0));
+}
+