Document directory structure in directoryDescription.md

Added a detailed description of the directory structure and its components.

directoryDescription.md

@@ -0,0 +1,23 @@
+
+# File structure
+| Directory| Description|
+|--|--|
+| McZapkie/ | Train Physics Engine |
+| gl/ |  OpenGL Abstraction Layer|
+| network/ |  Multiplayer Support
+| launcher/ |  Scenario/Vehicle Selection (built in starter)|
+| widgets/ |  HUD Elements |
+| vr/ |  Virtual Reality Support |
+| Console/ |  Hardware I/O |
+| application/ | Core simulation loop, time, environment, state serializer, sounds |
+| scene/ | Scene graph, scene nodes, scene editor, utilities |
+| rendering/ | All renderers (OpenGL legacy and full), geometry banks, particles, lights, frustum |
+| audio/ | Sound, audio, and audio renderer |
+| environment/ | Sky, sun, moon, stars, skydome | 
+| application/ | Application modes, UI layers/panels, driver/editor/scenario modes | 
+| input/ | Keyboard, mouse, gamepad, command, messaging, ZMQ input |
+| scripting/ | Lua, Python, ladder logic, screen viewer |
+| model/ | 3D models, materials, textures, resource manager |
+| utilities/ | Logging, timing, parsing, math, globals, crash reporter |
+| world/ | Tracks, traction, events, memory cells, stations | 
+| vehicle/ | Train, dynamic objects, driver, gauges, camera |