How engines are organised.
WHAT A SCENE IS
The collection of objects currently active.
WHAT AN ENTITY IS
An object in the world, with a position and behaviour.
WHAT THE COMPONENT MODEL IS
Entities composed of attached components providing capability, rather than deep inheritance.
WHY COMPOSITION BEAT INHERITANCE HERE
Game objects combine capabilities in arbitrary ways, which inheritance hierarchies cannot express.
WHAT THE UPDATE ORDER IS
The engine calling registered behaviours each frame, in a defined sequence.
WHY THAT ORDER MATTERS
Behaviours depending on each other break when the order changes.
WHAT TO NEVER RELY ON
Implicit ordering between independent components.
WHAT THE LIFECYCLE CALLBACKS ARE
Creation, activation, per-frame update, fixed update, and destruction.
WHAT TO PUT IN FIXED UPDATE
Physics and anything requiring consistent timing.
WHAT ASSET REFERENCES ARE
Links to content loaded from disk.
WHAT LOADING STRATEGY AFFECTS
Startup time and memory.
WHAT TO LOAD LAZILY
Anything not needed immediately.
WHAT A PREFAB OR SCENE TEMPLATE IS
A reusable configured object, instantiated many times.
WHY IT MATTERS
Changing one definition updates every instance.
