# ai_rail.cpp File Reference

Implementation of AIRail. More...

`#include "ai_rail.hpp"`
`#include "ai_map.hpp"`
`#include "ai_station.hpp"`
`#include "../../debug.h"`
`#include "../../station_map.h"`
`#include "../../company_func.h"`
`#include "../../waypoint.h"`
`#include "../../newgrf_generic.h"`
`#include "../../newgrf_station.h"`

Go to the source code of this file.

## Data Structures
struct | AIRailSignalData
| Contains information about the trackdir that belongs to a track when entering from a specific direction. More...
## Functions
static uint32 | SimulateDrag (TileIndex from, TileIndex tile, TileIndex *to)
| Prepare the second parameter for CmdBuildRailroadTrack and CmdRemoveRailroadTrack.
static bool | IsValidSignalType (int signal_type)
| Check if signal_type is a valid SignalType.
## Variables
static const int | NUM_TRACK_DIRECTIONS = 3
| The number of directions you can go when entering a tile.
static const AIRailSignalData | _possible_trackdirs [5][NUM_TRACK_DIRECTIONS]
| List information about the trackdir and number of needed cycles for building signals when entering a track from a specific direction.

## Detailed Description

Implementation of AIRail.

Definition in file ai_rail.cpp.

## Function Documentation

static uint32 SimulateDrag | ( | TileIndex | from,
|  | TileIndex | tile,
|  | TileIndex * | to |
| ) |  |  | `[static]`

Prepare the second parameter for CmdBuildRailroadTrack and CmdRemoveRailroadTrack.

The direction depends on all three tiles. Sometimes the third tile needs to be adjusted.

Definition at line 256 of file ai_rail.cpp.

References abs(), Clamp(), AIRail::GetCurrentRailType(), MapSizeX(), TileX(), TileY(), TRACK_LEFT, TRACK_LOWER, TRACK_RIGHT, TRACK_UPPER, TRACK_X, and TRACK_Y.

Referenced by AIRail::BuildRail(), and AIRail::RemoveRail().

## Variable Documentation

const AIRailSignalData _possible_trackdirs[5][NUM_TRACK_DIRECTIONS]`[static]`

Initial value:

     {
      {{TRACK_UPPER,   TRACKDIR_UPPER_E, 0}, {TRACK_Y,       TRACKDIR_Y_SE,    0}, {TRACK_LEFT,    TRACKDIR_LEFT_S,  1}},
      {{TRACK_RIGHT,   TRACKDIR_RIGHT_S, 1}, {TRACK_X,       TRACKDIR_X_SW,    1}, {TRACK_UPPER,   TRACKDIR_UPPER_W, 1}},
      {{INVALID_TRACK, INVALID_TRACKDIR, 0}, {INVALID_TRACK, INVALID_TRACKDIR, 0}, {INVALID_TRACK, INVALID_TRACKDIR, 0}},
      {{TRACK_LOWER,   TRACKDIR_LOWER_E, 0}, {TRACK_X,       TRACKDIR_X_NE,    0}, {TRACK_LEFT,    TRACKDIR_LEFT_N,  0}},
      {{TRACK_RIGHT,   TRACKDIR_RIGHT_N, 0}, {TRACK_Y,       TRACKDIR_Y_NW,    1}, {TRACK_LOWER,   TRACKDIR_LOWER_W, 1}}
    }

List information about the trackdir and number of needed cycles for building signals when entering a track from a specific direction.

The first index is the difference between the TileIndex of the previous and current tile, where (-)MapSizeX is replaced with -2 / 2 and 2 it added.

Definition at line 366 of file ai_rail.cpp.