Custom Train Tracks

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This branch makes it possible to make your own train tracks.

Status Work in progress
Branch feature/custom-train-tracks
Branch version 1.5.3

Functions

Media

Development

API

-- trainNode is a Vector3, or table of three coordinates
-- nodes is a table of trainNodes

track = TrainTrack(...nodes) -- createTrack(node1, node2, node3, ...)
track:getNodes() returns a table of Vector3s
track:getLength() -- getTrainTrack(track)
-- Default track functions
TrainTrack.removeDefault(int trackID)
TrainTrack.resetDefault(int trackID)

-- These functions already exist, but I'm not sure how these lengths are used or what they are for

Findings

All information related custom train tracks are stored here.

Files

MTA10/game_sa
** CTrainTrackManagerSA.{cpp,h}
** CTrainTrackSA.{cpp,h}

MTA10/mods/shared_logic
** CClientTrainTrack.{cpp,h}
** luadefs/CLuaTrainTrackDefs.{cpp,h} -- contain definitions for the Lua API

MTA10/sdk/game
** CTrainTrack.h
** CTrainTrackManager.h

MTA10_Server/mods/deathmatch/logic
** CTrainTrackManager.{cpp,h}
** CTrainTrack.{cpp,h}
** luadefs/CLuaTrainTrackDefs.{cpp,h} -- contain definitions for the Lua API

m_OriginalTrainTrackData

The m_OriginalTrainTrackData array contains the same values in CTrainTrackManager.cpp and CTrainTrackManagerSA.cpp.

The Init function is structured like so (pay special attention to the comments):

typedef struct
{
    short sX;               // x coordinate times 8
    short sY;               // y coordinate times 8
    short sZ;               // z coordinate times 8
    float fRailDistance;    // on-rail distance ( leave the client to calculate this )
    void Init ( short sX, short sY, short sZ, unsigned short sRailDistance, WORD padding )
    {
        this->sX = sX;
        this->sY = sY;
        this->sZ = sZ;
        this->fRailDistance = sRailDistance;
    }
} SRailNode;

We need to make sense of the following things:

  • Why is padding an argument here? (It doesn't do anything, and when Init() is called, real values are provided)
  • Why are values repeated several times?
  • Why does the last repeat have slightly different values?

Issues

  • There may be some issues (relating to infinite loops) if a track runs across another or crosses another
    • Infinite loop occurs at 006f8fda, see call stack. Occurs when a track of two nodes have same x/y, but different z. Only occurs for tracks that ONLY consist of nodes atop each other.
      • Possible solution: when creation tracks, ensure that atleast one of the nodes has a different x/y to any other node.
  • Tracks may not be cleaned up -> See CTrainTrackManager::ResetTracks
  • See CTrainTrackManager and CTrainTrackManagerSA - why is this file so big? Why are coordinates provided multiple times for the same track? Which ones are right?
  • int CWorldSA::FindClosestRailTrackNode needs updating. It needs to use MAX_TOTAL_TRACKS and the train manager. See 09e3ee8f25810c17742

Re-merge

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