Math/Plane: Fix construction from 3 points

include/Nazara/Math/Frustum.inl

@@ -460,7 +460,7 @@ namespace Nz
 		T farW = farH * ratio;
 
 		Vector3<T> f = Vector3<T>::Normalize(target - eye);
-		Vector3<T> u(up.GetNormal());
+		Vector3<T> u = Vector3<T>::Normalize(up);
 		Vector3<T> s = Vector3<T>::Normalize(f.CrossProduct(u));
 		u = s.CrossProduct(f);
 

include/Nazara/Math/Plane.hpp

@@ -17,6 +17,8 @@ namespace Nz
 	template<typename T>
 	class Plane
 	{
+		// Note: this class follows the ax + by + cz + d = 0 equation, which means d is the distance from origin
+
 		public:
 			constexpr Plane() = default;
 			constexpr Plane(T normalX, T normalY, T normalZ, T Distance);

include/Nazara/Math/Plane.inl

@@ -88,7 +88,7 @@ namespace Nz
 		normal = edge1.CrossProduct(edge2);
 		normal.Normalize();
 
-		distance = normal.DotProduct(point3);
+		distance = -normal.DotProduct(point3);
 	}
 
 	/*!
@@ -139,7 +139,7 @@ namespace Nz
 	template<typename T>
 	constexpr T Plane<T>::SignedDistance(const Vector3<T>& point) const
 	{
-		return normal.DotProduct(point) + distance; // ax + by + cz + d = 0.
+		return normal.DotProduct(point) + distance; // ax + by + cz + d = 0
 	}
 
 	/*!