Rearrenged the directory tree

I just _had_ to get rid of that horrible libs/ directory. Now most of the
graphical stuff is in client/, but I'll create more subdirectories so that
they're not getting in the way.

common/vector2.hpp

@@ -0,0 +1,110 @@
+/* Copyright: (c) Kayne Ruse 2013
+ * 
+ * This software is provided 'as-is', without any express or implied
+ * warranty. In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ * 
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ * 
+ * 1. The origin of this software must not be misrepresented; you must not
+ * claim that you wrote the original software. If you use this software
+ * in a product, an acknowledgment in the product documentation would be
+ * appreciated but is not required.
+ * 
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ * misrepresented as being the original software.
+ * 
+ * 3. This notice may not be removed or altered from any source
+ * distribution.
+*/
+#ifndef VECTOR2_HPP_
+#define VECTOR2_HPP_
+
+#include <stdexcept>
+#include <cmath>
+
+class Vector2 {
+public:
+	double x = 0, y = 0;
+	Vector2() = default;
+
+	double Length() const {
+		return sqrt(x*x+y*y);
+	}
+	double SquaredLength() const {
+		return x*x+y*y;
+	}
+
+	double operator[](size_t i) {
+		if (i >= 2)
+			throw(std::domain_error("Out of range"));
+		return *(&x+i);
+	}
+
+	//Arithmetic operators
+	Vector2 operator+(Vector2 v) const {
+		Vector2 ret;
+		ret.x = x + v.x;
+		ret.y = y + v.y;
+		return ret;
+	}
+	Vector2 operator-(Vector2 v) const {
+		Vector2 ret;
+		ret.x = x - v.x;
+		ret.y = y - v.y;
+		return ret;
+	}
+	Vector2 operator*(Vector2 v) const {
+		Vector2 ret;
+		ret.x = x * v.x;
+		ret.y = y * v.y;
+		return ret;
+	}
+	Vector2 operator*(double d) const {
+		Vector2 ret;
+		ret.x = x * d;
+		ret.y = y * d;
+		return ret;
+	}
+
+	Vector2 operator/(Vector2 v) {
+		if (!v.x || !v.y)
+			throw(std::domain_error("Divide by zero"));
+		Vector2 ret;
+		ret.x = x / v.x;
+		ret.y = y / v.y;
+		return ret;
+	}
+	Vector2 operator/(double d) {
+		if (!d)
+			throw(std::domain_error("Divide by zero"));
+		Vector2 ret;
+		ret.x = x / d;
+		ret.y = y / d;
+		return ret;
+	}
+
+	bool operator==(Vector2 v) { return (x == v.x && y == v.y); }
+	bool operator!=(Vector2 v) { return (x != v.x || y != v.y); }
+
+	//member templates
+	template<typename T> Vector2 operator+=(T t) { return *this = *this + t; }
+	template<typename T> Vector2 operator-=(T t) { return *this = *this - t; }
+	template<typename T> Vector2 operator*=(T t) { return *this = *this * t; }
+	template<typename T> Vector2 operator/=(T t) { return *this = *this / t; }
+	template<typename T> bool operator==(T t) { return (x == t && y == t); }
+	template<typename T> bool operator!=(T t) { return (x != t || y != t); }
+};
+
+//non-member templates
+template<typename T> Vector2 operator+(T t, Vector2 v) { return v + t; }
+template<typename T> Vector2 operator-(T t, Vector2 v) { return v - t; }
+template<typename T> Vector2 operator*(T t, Vector2 v) { return v * t; }
+template<typename T> Vector2 operator/(T t, Vector2 v) { return v / t; }
+
+template<typename T> bool operator==(T t, Vector2 v) { return v == t; }
+template<typename T> bool operator!=(T t, Vector2 v) { return v != t; }
+
+#endif