From b41cdb7186f48b995130a3074c53fa2fe096c7f7 Mon Sep 17 00:00:00 2001
From: Eryn Wells <eryn@erynwells.me>
Date: Sat, 9 Aug 2014 09:32:48 -0700
Subject: [PATCH] Vector4 +, -, negation, and *

+, -, and negation were easy. Multiplication is wacky because the Matrix class does it. So, to do binary * (not *=) I needed to dynamic_cast the resulting Matrix<4,1> to a Vector4&&.
---
 src/basics/vector.cc | 81 ++++++++++++++++++++++++++++++++++++++++++++
 src/basics/vector.hh | 13 +++++++
 2 files changed, 94 insertions(+)

diff --git a/src/basics/vector.cc b/src/basics/vector.cc
index e2913d5..5f68bfa 100644
--- a/src/basics/vector.cc
+++ b/src/basics/vector.cc
@@ -78,6 +78,9 @@ Vector4::Z()
 }
 
 
+/*
+ * charles::basics::Vector4::Z --
+ */
 const Double&
 Vector4::Z()
     const
@@ -86,6 +89,73 @@ Vector4::Z()
 }
 
 
+/*
+ * charles::basics::Vector4::operator* --
+ */
+Vector4
+Vector4::operator*(const Double& rhs)
+    const
+{
+    return dynamic_cast<Vector4&&>(*this * rhs);
+}
+
+
+/*
+ * charles::basics::Vector4::operator+ --
+ */
+Vector4
+Vector4::operator+(const Vector4& rhs)
+    const
+{
+    return Vector4(*this) += rhs;
+}
+
+
+/*
+ * charles::basics::Vector4::operator+= --
+ */
+Vector4&
+Vector4::operator+=(const Vector4& rhs)
+{
+    mData[0] += rhs.mData[0];
+    mData[1] += rhs.mData[1];
+    mData[2] += rhs.mData[2];
+    return *this;
+}
+
+
+/*
+ * charles::basics::Vector4::operator- --
+ */
+Vector4
+Vector4::operator-(const Vector4& rhs)
+    const
+{
+    return Vector4(*this) -= rhs;
+}
+
+
+/*
+ * charles::basics::Vector4::operator-= --
+ */
+Vector4&
+Vector4::operator-=(const Vector4& rhs)
+{
+    return *this += -rhs;
+}
+
+
+/*
+ * charles::basics::Vector4::operator- --
+ */
+Vector4
+Vector4::operator-()
+    const
+{
+    return Vector4(-X(), -Y(), -Z());
+}
+
+
 /*
  * charles::basics::Vector4::Length2 --
  */
@@ -146,6 +216,17 @@ Vector4::Normalize()
     return *this;
 }
 
+
+/*
+ * charles::basics::operator* --
+ */
+Vector4
+operator*(const Double& lhs,
+          const Vector4& rhs)
+{
+    return rhs * lhs;
+}
+
 } /* namespace basics */
 } /* namespace charles */
 
diff --git a/src/basics/vector.hh b/src/basics/vector.hh
index 4440e69..9f34437 100644
--- a/src/basics/vector.hh
+++ b/src/basics/vector.hh
@@ -32,6 +32,15 @@ struct Vector4
     Double& Z();
     const Double& Z() const;
 
+    Vector4 operator*(const Double& rhs) const;
+
+    Vector4 operator+(const Vector4& rhs) const;
+    Vector4& operator+=(const Vector4& rhs);
+    Vector4 operator-(const Vector4& rhs) const;
+    Vector4& operator-=(const Vector4& rhs);
+
+    Vector4 operator-() const;
+
     /** Get the length-squared of this vector. */
     Double Length2() const;
 
@@ -49,6 +58,10 @@ struct Vector4
 };
 
 
+/** Scalar multiplication of vectors, with the scalar factor on the left. */
+Vector4 operator*(const Double& lhs, const Vector4& rhs);
+
+
 /** Normalize the given vector and return a copy of it. */
 Vector4& Normalized(const Vector4& v);