Modified SceneNode::FrustumCull

Now provides an implementation which will test the bounding volume
against the frustum (Basic frustum culling)
Is now const
Disabled face culling on sprites


Former-commit-id: 5cb7a94b38ef8b0ffa5a78f16f5ef65a59ab375d

include/Nazara/Graphics/Sprite.hpp

@@ -37,7 +37,6 @@ class NAZARA_API NzSprite : public NzSceneNode
 		void SetTextureRect(const NzRectui& rect);
 
 	private:
-		bool FrustumCull(const NzFrustumf& frustum) override;
 		void InvalidateNode() override;
 		void Register() override;
 		void Unregister() override;