Change value initialization of vector types

Always zero-initialize vectors and quaternions - the performance
tradeoff is worth the security.
Add a missing quaternion exact-equality operator.

src/Quaternion.h

@@ -61,6 +61,15 @@ class Quaternion {
 			axis.z = z / s;
 		}
 	}
+	bool operator==(const Quaternion &a) const
+	{
+		return is_equal_exact(a.w, w) && is_equal_exact(a.x, x) && is_equal_exact(a.y, y) && is_equal_exact(a.z, z);
+	}
+	bool ExactlyEqual(const Quaternion &a) const
+	{
+		return is_equal_exact(a.w, w) && is_equal_exact(a.x, x) && is_equal_exact(a.y, y) && is_equal_exact(a.z, z);
+	}
+
 	// conjugate (inverse)
 	friend Quaternion operator~(const Quaternion &a)
 	{
@@ -234,9 +243,17 @@ class Quaternion {
 };
 
 template <>
-inline Quaternion<float>::Quaternion() {}
+inline Quaternion<float>::Quaternion() :
+	w(1.f),
+	x(0.f),
+	y(0.f),
+	z(0.f) {}
 template <>
-inline Quaternion<double>::Quaternion() {}
+inline Quaternion<double>::Quaternion() :
+	w(1.),
+	x(0.),
+	y(0.),
+	z(0.) {}
 template <>
 inline Quaternion<float>::Quaternion(float w_, float x_, float y_, float z_) :
 	w(w_),

src/vector2.h

@@ -111,9 +111,13 @@ class vector2 {
 };
 
 template <>
-inline vector2<float>::vector2() {}
+inline vector2<float>::vector2() :
+	x(0.f),
+	y(0.f) {}
 template <>
-inline vector2<double>::vector2() {}
+inline vector2<double>::vector2() :
+	x(0.),
+	y(0.) {}
 template <>
 inline vector2<float>::vector2(const vector2<double> &v) :
 	x(float(v.x)),

src/vector3.h

@@ -10,10 +10,10 @@
 #include <stdio.h>
 
 // Need this pragma due to operator[] implementation.
-// #pragma pack(4)
+#pragma pack(4)
 
 template <typename T>
-class vector3 {
+class alignas(sizeof(T)) vector3 {
 public:
 	T x, y, z;
 
@@ -280,9 +280,18 @@ inline vector3<double>::vector3(const double vals[3]) :
 	z(vals[2])
 {}
 
-// #pragma pack()
+#pragma pack()
 
 typedef vector3<float> vector3f;
 typedef vector3<double> vector3d;
 
+// ensure both packing and structure alignment match the constraints we have set
+static_assert(alignof(vector3d) == 8);
+static_assert(offsetof(vector3d, y) == 8);
+static_assert(offsetof(vector3d, z) == 16);
+
+static_assert(alignof(vector3f) == 4);
+static_assert(offsetof(vector3f, y) == 4);
+static_assert(offsetof(vector3f, z) == 8);
+
 #endif /* _VECTOR3_H */