OpenTTD Source: Modules

OpenTTD Source 13.1

Modules
Here is a list of all modules:

Dirty | Handles the repaint of some part of the screen
Snowline functions and data structures |
Rows and columns in the viewport | Columns are vertical sections of the viewport that are half a tile wide. The origin, i.e. column 0, is through the northern and southern most tile. This means that the column of e.g. Tile(0, 0) and Tile(100, 100) are in column number 0. The negative columns are towards the left of the screen, or towards the west, whereas the positive ones are towards respectively the right and east. With half a tile wide is meant that the next column of tiles directly west or east of the centre line are respectively column -1 and 1. Their tile centers are only half a tile from the center of their adjoining tile when looking only at the X-coordinate
Hierarchical widgets | Hierarchical widgets, also known as nested widgets, are widgets stored in a tree. At the leafs of the tree are (mostly) the 'real' widgets visible to the user. At higher levels, widgets get organized in container widgets, until all widgets of the window are merged
Hierarchical widget parts | To make nested widgets easier to enter, nested widget parts have been created. They allow the tree to be defined in a flat array of parts