I am not engine expert, what is the meaning of that? Is A7 has this feature?
Unified per-pixel lighting with everything casting and receiving shadows is something like the heaven for level designers. It is simple to use, no pre-compiling, only placing objects, placing lights and seeing the results instantly.
"everything casting and receiving shadows" is great in combination with "unified". So even the level geometry (maybe a pillar) could cast a shadow to your moving character while the character also casts shadows to the pillar.
But level geometry still has the advantages like scene-management and fast collision detection while looking as great as a model-based scene.
"Unified" can describe different meanings. In terms of GarageGames or A7 it can mean that everything reacts the same in terms of materials, shaders, lights and shadows, no matter if you use models, level geometry (even foliage could react very similar).
The Leadwerks engine reads the levels from their own level editor - a bsp brush based editor. So they allow the same lighting on models and level geometry. This is not the case with Torque or A7. So they indeed have a more advanced technology in terms of useablility.
Per-pixel simply means that lighting does not work per vertex / polygon. It calculates the bright and darker spots on the model for every pixel and thus results in more realistic and better looking lighting scenarios.
This is possible in many engines via shaders. But the latest ones use this method even for default lighting, especially if the render kernel is shader based.
A7, TGE and other older tools use per-vertex lighting as default (if you do not add a shader material to a model).
The disadvantage of per-vertex lighting is: You sometimes see single polygons on the model and light distributes bad on lowpoly models. That is one of the reasons why there is a function in the level compiler of Gamestudio to subdivide the level geometry. It is to allow better light distribition.
