servicepoint-tanks

Backend

• Uses the C# bindings from the servicepoint library for communication with the display.
• Stack: .NET / C# / ASP.NET / AOT-compiled
• Both traditional JSON over HTTP APIs and real-time WebSocket communication
• runs all game logic
• sends image and text to the service point display
• sends image to clients
• The game has a dynamic update rate. Hundreds of updates per second on a laptop are expected.
• One frame is ~7KB, not including the text and player specific data
• maps can be loaded from png files containing black and white pixels or simple text files
• some values (like tank speed) can be configured but are fixed at run time
• By default, the backend also hosts the frontend

Frontend

• Stack: React / Vite / TypeScript / plain CSS
• There is no server component dedicated to the frontend, everything is a single page after build
• Shows map rendered on server by setting canvas image data
• Sends user input to server
• real time communication via WebSockets, HTTP for the REST

Binary formats

Controls WebSocket

• Client sends 2 byte messages.
  • on or off: 0x01 or 0x02
  • input: Forward=0x01, Backward=0x02, Left=0x03, Right=0x04, Shoot=0x05
• The server never sends any messages.

Observer screen WebSocket

• same image for all clients
• server sends same format as for the service point display
• client responds with empty message to request the next frame

Player screen WebSocket

• image is rendered per player
• server sends same message as the observer WebSocket, but includes an additional 4 bits per set bit in the observer payload
  • first bit: belongs to current player
  • second bit: (reserved)
  • third and fourth bit: type of something
    • 00: wall
    • 01: tank
    • 10: bullet
    • 11: (reserved)
• client responds with empty message to request the next frame