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/Graphics/PointLight.inl

@@ -28,14 +28,19 @@ namespace Nz
 		return m_color;
 	}
 
+	inline float PointLight::GetDiffuseFactor() const
+	{
+		return m_diffuseFactor;
+	}
+
 	inline const Vector3f& PointLight::GetPosition() const
 	{
 		return m_position;
 	}
 
-	inline float PointLight::GetDiffuseFactor() const
+	inline float PointLight::GetInvRadius() const
 	{
-		return m_diffuseFactor;
+		return m_invRadius;
 	}
 
 	inline float PointLight::GetRadius() const