Cross-Realm Entity Bridge

This project is a 10-day technical challenge demonstrating an entity (a glowing orb) that exists and persists across two separate applications: a low-level OpenGL C++ simulation and a high-level Unreal Engine 4 game.

The "bridge" between them is a shared entity_state.json file. The OpenGL app acts as the "physics authority," saving its state, while the UE4 app loads that state to recreate the entity with identical mechanics.

How to Run

Place the OGL_Build (or ogl_port.exe and its assets) and the UE4_Build (e.g., WindowsNoEditor) folders in the same directory.

Run the OpenGL app first (ogl_port.exe). Interact with the orb and press 'S' to save (or just close it). This will create/update entity_state.json.

Run the UE4 app (cross_realm_ue4.exe). The orb will spawn in the state you saved.

You can use the 'L' key in UE4 to "hot-reload" the JSON file after saving new changes in the OGL app.

Controls

OpenGL (ogl_port.exe)

Key

Action

WASD

Move Camera

Space / L-Shift

Move Camera Up / Down

Mouse

Look Camera

E (Hold)

Interact (Gain Energy)

G

Toggle Gravity

R

Reset Orb Position

S

Save Current State to JSON

Esc

Exit Application

Unreal Engine 4 (cross_realm_ue4.exe)

Key

Action

WASD

Move Camera

Mouse

Look Camera

F (Hold)

Interact (Gain Energy)

G

Toggle Gravity

R

Reset Orb Position

L

Load/Reload State from JSON

Shift + F1

Show / Hide Mouse Cursor