Alundra

Do you mean to have a root node and have children in it and have with that an array of SceneObject who is just all objects ?

Use the recursion to save/load and the array for other operations ?

Best solution to what?

To traverse the tree for saving the scene, find an object by name or pointer, update each object and render the scene.

I have always listen that recursion is slow because of the cache miss.

For a QuickSort algorithm the solution is to have a MaxLevel variables en switch to InsertionSort if MaxLevel is reached.

For a a scene tree the best solution is to use recursion ?

You can combine two methods if your light doesn't rotate. You can generate the lightmap for static scene and use the shadow mapping using an ortho projection for dynamic objects. The best is SDSM, Vilem Otte gave the link of the paper, you can found the demo source who is Direct3D11 based. It's important to notice that SDSM needs compute shader, without compute shader you will need to read back a lot and you will lost performance.

You can use SDL for the unix version to handle window and input.

Quake4, Unreal Tournament, Unreal Tournament 2003, Unreal Tournament 2004, and many other do that.

You can change the window/input code after, SDL is here to make you winning time.