Map array (landscape grid)
OpenTTD Development Documentation
External Links

OpenTTD GitHub
Contributing to OpenTTD - guidelines
OpenTTD Doxygen

General Reference

Coding style
Compiling OpenTTD
Add a setting
Add a squirrel function
Understanding the SaveGame handler
Bumping the savegame version
Doing an OpenTTD release

Language and Strings

Manual of style
Format of langfiles
Using OpenTTD strings
List of special strings

Window System

Using the window system
Colour codes that exist in OpenTTD
Adding a text box
Understanding the widget focus system
GUI style guide


The OpenTTD TCP protocol
The OpenTTD UDP protocol
Debugging desyncs
Server Admin Port development

Ingame Console

The console window
Console commands
Console variables
Using console scripting
Adding functions/commands to the console
Adding variables to the console
Console development history

Content APIs (modding frameworks)

Graphics and similar (NewGRF)
AI framework (NoAI)
GameScript framework (NoGO)
Social Integration

Other Reference

Map array (landscape grid)
Train acceleration
Sound IDs

The map array is a key concept in many cases when developing for OpenTTD.

The GitHub docs folder contains two documents which show the arrangement of bytes in the map array, and the features they represent.

These are html documents, which GitHub does not (as of October 2019) display as html in the browser.

If you have a git checkout of OpenTTD source, the landscape docs can be opened locally in a browser from the /docs folder.

(At your own risk) they can also be viewed in the browser with a github->html converter service: