Add of some mathematical functions

Plane: Getters and classic planes
Sphere: Getter
Vector2: Angle between two vectors
Vector3: Same in 3D

Former-commit-id: 07e6421def813743e5fd8248fe2e9503cebbb8a8

include/Nazara/Math/Plane.inl

@@ -58,6 +58,18 @@ T NzPlane<T>::Distance(T x, T y, T z) const
 	return Distance(NzVector3<T>(x, y, z));
 }
 
+template<typename T>
+NzVector3 NzPlane<T>::GetNormal() const
+{
+    return normal;
+}
+
+template<typename T>
+T NzPlane<T>::GetDistance() const
+{
+    return distance;
+}
+
 template<typename T>
 NzPlane<T>& NzPlane<T>::Set(T normalX, T normalY, T normalZ, T D)
 {
@@ -152,6 +164,24 @@ NzPlane<T> NzPlane<T>::Lerp(const NzPlane& from, const NzPlane& to, T interpolat
 	return plane;
 }
 
+template<typename T>
+NzPlane<T> NzPlane<T>::XY()
+{
+    return NzPlane<T>(F(0.0), F(0.0), F(1.0), F(0.0));
+}
+
+template<typename T>
+NzPlane<T> NzPlane<T>::XZ()
+{
+    return NzPlane<T>(F(0.0), F(1.0), F(0.0), F(0.0));
+}
+
+template<typename T>
+NzPlane<T> NzPlane<T>::YZ()
+{
+    return NzPlane<T>(F(1.0), F(0.0), F(0.0), F(0.0));
+}
+
 template<typename T>
 std::ostream& operator<<(std::ostream& out, const NzPlane<T>& plane)
 {