Graphics: Rework shadowing (add cascaded shadow mapping)

- Add support for per-viewer shadows
- Add cascaded shadow mapping for directional lights (wip)
- Rework the way lights are sent to the shaders (they are now selected once per viewer)
- Fixes PointLight shadow mapping (using a dedicated pass)
- Lights out of frustum for every viewers are no longer processed (wip)

include/Nazara/Math/Frustum.hpp

@@ -56,6 +56,11 @@ namespace Nz
 			constexpr IntersectionSide Intersect(const Sphere<T>& sphere) const;
 			constexpr IntersectionSide Intersect(const Vector3<T>* points, std::size_t pointCount) const;
 
+			constexpr Frustum<T> Reduce(T nearFactor, T farFactor) const;
+
+			template<typename F> constexpr void Split(std::initializer_list<T> splitFactors, F&& callback) const;
+			template<typename F> constexpr void Split(const T* splitFactors, std::size_t factorCount, F&& callback) const;
+
 			std::string ToString() const;
 
 			constexpr Frustum& operator=(const Frustum&) = default;