mtf2json 0.1.3

Convert the MegaMek MTF format to JSON.

mtf2json

mtf2json converts MegaMek's MTF file format to JSON.

Project Goals and Features

• Make it easy to parse MTF files in any modern programming language, using a well-known and documented format (JSON).
• Provide a comprehensive JSON structure that includes all necessary data for generating record sheets.
• Handle various issues and inconsistencies in the MTF format.

Why mtf2json?

MegaMek is a great project, but the MTF format is difficult to work with. It's not a standardized format and there is no official specification (at least I couldn't find one). Furhermore, an MTF file does not contain all information required to create an actual record sheet (e.g. the structure pips are missing).

mtf2json does not simply create a 1:1 JSON version of the MTF data (that wouldn't be possible anyway) but restructures the data and adds information that is required for creating record sheets (see examples below).

Limitations and Supported Versions

Quad Mechs

Currently, mtf2json can only convert MTF files of biped mechs.

Supported MegaMek Version

0.49.19.1

Testing

Testing mtf2json is challenging, mostly because the MTF format is so loosely specified. I'm still not sure if I've actually seen all possible keys and understood all supported value syntaxes. Since there are over 4000 MTF files in MegaMek, I can't test and manually verify them all. If you have trouble converting an MTF file, create a Github issue and append the file, so I can verify and fix the issue.

JSON Structure and Examples

Here are some comparisons of sections from an MTF file and their JSON counterpart:

The Basic Stuff

MTF:

chassis:Atlas
model:AS7-K
mul id:144

JSON:

"chassis": "Atlas",
"model": "AS7-K",
"mul_id": 144,

Most of the "flat" key:value pairs are also stored as key:value pairs in JSON. However, number values are stored as int if appropriate (they remain strings if they are used as names or model designation).

Rules Level

MTF:

Rules Level:2

JSON:

"rules_level": 2,
"rules_level_str": "Standard",

A string version of the rules level is automatically added. It's intended to be used in the record sheet and determined using the same algorithm as MegaMek.

Quirks

MTF:

quirk:battle_fists_la
quirk:battle_fists_ra
quirk:command_mech
quirk:distracting
quirk:imp_com

JSON:

"quirks": [
    "battle_fists_la",
    "battle_fists_ra",
    "command_mech",
    "distracting",
    "imp_com"
],

No more dealing with multiple identical keys. Just a simple JSON list.

Heat Sinks

MTF:

Heat Sinks:20 Single

JSON:

"heat_sinks": {
    "quantity": 20,
    "type": "Single"
},

Type and quantity of heat sinks are separate keys, no need for additional parsing.

Movement Points

MTF:

Walk MP:3
Jump MP:0

JSON:

"walk_mp": 3,
"run_mp": 5,
"jump_mp": 0,

The movement points for running are calculated automatically, for your convenience.

Armor

MTF:

armor:Standard(Inner Sphere)
LA armor:34
RA armor:34
LT armor:32
RT armor:32
CT armor:47
HD armor:9
LL armor:41
RL armor:41
RTL armor:10
RTR armor:10
RTC armor:14

JSON:

"armor": {
  "type": "Standard",
  "tech_base": "Inner Sphere"
  "pips": {
    "left_arm": 34,
    "right_arm": 34,
    "left_torso": {
      "front": 32,
      "rear": 10
    },
    "right_torso": {
      "front": 32,
      "rear": 10
    },
    "center_torso": {
      "front": 47,
      "rear": 14
    },
    "head": 9,
    "left_leg": 41,
    "right_leg": 41
  },
},

Armor type, tech base (if available) and pips are stored in the armor section. Note that the tech base is not always available in the MTF file (i.e. sometimes it's "Standard Armor", sometimes "Standard(Inner Sphere))". Maybe "Standard" always means "Inner Sphere", but I'm not sure, so I leave out the tech_base entry in that case.

Weapons

MTF:

Weapons:3
1 ISGaussRifle, Right Torso, Ammo:16
1 ISERLargeLaser, Left Arm
2 ISMediumPulseLaser, Center Torso (R)

JSON:

"weapons": {
    "1": {
        "ISGaussRifle": {
            "location": "right_torso",
            "facing": "front",
            "quantity": 1,
            "ammo": 16
        }
    },
    "2": {
        "ISERLargeLaser": {
            "location": "left_arm",
            "facing": "front",
            "quantity": 1
        }
    },
    "3": {
        "ISMediumPulseLaser": {
            "location": "center_torso",
            "facing": "rear",
            "quantity": 2
        }
    },
},

Location, facing, quantity and ammo are all individual keys of each weapon. Additionally, each weapon has a slot number that represents the order in the MTF file (and on the record sheet). Some MTF files contain individual entries even for identical weapons in the same location (i.e. no quantity at the beginning of the line). Those entries are automatically merged.

Structure

MTF:

structure:IS Standard

JSON:

"structure": {
    "type": "Standard",
    "tech_base": "Inner Sphere",
    "pips": {
        "head": 3,
        "center_torso": 31,
        "left_torso": 21,
        "right_torso": 21,
        "left_arm": 17,
        "right_arm": 17,
        "left_leg": 21,
        "right_leg": 21
    }
},

Structure type and tech base (if available) are stored in the structure section. The pips are added afterwards, based on the mech's tonnage. "IS" is converted to "Inner Sphere", in order to be consistent to the tech base naming in the armor section. Note that the tech base is not always available in the MTF file (i.e. sometimes it's "IS Standard", sometimes just "Standard"). Maybe "Standard" always means "Inner Sphere", but I'm not sure, so I leave out the tech_base entry in that case.

Critical Slots

MTF:

Left Arm:
Shoulder
Upper Arm Actuator
Lower Arm Actuator
Hand Actuator
Heat Sink
Heat Sink
ISERLargeLaser
ISERLargeLaser
ISAntiMissileSystem
-Empty-
-Empty-
-Empty-

JSON:

"critical_slots": {
  "left_arm": {
    "1": "Shoulder",
    "2": "Upper Arm Actuator",
    "3": "Lower Arm Actuator",
    "4": "Hand Actuator",
    "5": "Heat Sink",
    "6": "Heat Sink",
    "7": "ISERLargeLaser",
    "8": "ISERLargeLaser",
    "9": "ISAntiMissileSystem",
    "10": null,
    "11": null,
    "12": null
  },
}

All critical slots data is stored in the critical_slots section, with one section per location. Every slot has the slot number as key, making it very easy to check the content of each slot directly. The -Empty- string is replaced by an actual null (python None).

Fluff

MTF:

overview:The Banshee, introduced in 2445 by the Terran Hegemony, is a 'Mech that was designed specifically for close-assault operations during the early years of BattleMech warfare.
capabilities:A contemporary of the Mackie and Emperor, the Banshee is undeniably fast for one of the heaviest 'Mechs ever produced, and with fifteen tons of armor it is better protected than most other assault 'Mechs. However the use of a massive GM 380 fusion engine left little room for weaponry, and even at the time of its introduction the Banshee was considered undergunned compared to its privately-built competition. As critics noted, what use was impressive armor and mobility if a better-armed enemy could overwhelm and destroy it? The result was a mediocre 'Mech which even the lowly Rifleman could beat as long as it prevented the Banshee's mass from coming into play.
deployment:The two primary weapons on the Banshee, a Magna Hellstar PPC matched up with an Imperator-A Autocannon/5 with one ton of ammo, are mounted in the right and left sides of its torso. The two systems complement each other with similar range profiles and would provide good firepower for a 'Mech weighing at half the tonnage of the Banshee. Perversely for a close-combat 'Mech their minimum ranges means both weapons present targeting difficulties as the Banshee closes in on its enemy, and a Magna Mk I Small Laser mounted in its head appears to have been installed as an afterthought. Sixteen heat sinks help keep the 'Mech cool though, and thanks to its prodigious size the Banshee can turn lighter 'Mechs to scrap in hand-to-hand fighting.
history: The Hegemony soldiered on though, producing five thousand Banshees in a decade before its poor combat performance finally forced them to stop production in 2455 and the 'Mech was relegated to training and militia units for the next few centuries. Even during the Succession Wars the 'Mech's poor reputation meant many commanders saw it as a liability rather than an asset; unless they were fighting on a backwater Periphery world or as part of a poorly-equipped outfit, most Banshees were placed in second-line reserves to provide fire support or fulfill the role of brawlers so that better-armed 'Mechs need not engage in hand-to-hand combat. In this way fully a third of the original Banshee production run remained operational by the dawn of the thirty-first century and could be found throughout the Inner Sphere and Periphery, with the lion's share residing within the Lyran Commonwealth. Though a few attempts had been made over the years to improve the Banshee, Defiance Industries was the first to produce a variant which markedly improved on the original and was suggested by many of its original critics. With help from the Federated Suns and access to blueprints from the original Hesperus II factories, the BNC-3S proved to be such a success the Lyrans began fielding them in front line units, surprising their enemies who ignored them to focus on "real" threats with thoroughly unexpected firepower. Under the Federated Commonwealth improvements would continue to be made, though not at the same priority level as other projects, and the much-improved BNC-5S was active in time to meet the Clan Invasion.
manufacturer:Diplass BattleMechs,Witten Industries,Defiance Industries,Star League Weapons Research
primaryfactory:Apollo,Hesperus II,Hesperus II,New Earth
systemmanufacturer:CHASSIS:Star League
systemmode:CHASSIS:XT
systemmanufacturer:ENGINE:GM
systemmode:ENGINE:380
systemmanufacturer:ARMOR:Starshield
systemmanufacturer:COMMUNICATIONS:Dalban
systemmode:COMMUNICATIONS:Commline
systemmanufacturer:TARGETING:Dalban
systemmode:TARGETING:HiRez-B

JSON:

"fluff": {
  "overview": "The Banshee, introduced in 2445 by the Terran Hegemony, is a 'Mech that was designed specifically for close-assault operations during the early years of BattleMech warfare.",
  "capabilities": "A contemporary of the Mackie and Emperor, the Banshee is undeniably fast for one of the heaviest 'Mechs ever produced, and with fifteen tons of armor it is better protected than most other assault 'Mechs. However the use of a massive GM 380 fusion engine left little room for weaponry, and even at the time of its introduction the Banshee was considered undergunned compared to its privately-built competition. As critics noted, what use was impressive armor and mobility if a better-armed enemy could overwhelm and destroy it? The result was a mediocre 'Mech which even the lowly Rifleman could beat as long as it prevented the Banshee's mass from coming into play.",
  "deployment": "The two primary weapons on the Banshee, a Magna Hellstar PPC matched up with an Imperator-A Autocannon/5 with one ton of ammo, are mounted in the right and left sides of its torso. The two systems complement each other with similar range profiles and would provide good firepower for a 'Mech weighing at half the tonnage of the Banshee. Perversely for a close-combat 'Mech their minimum ranges means both weapons present targeting difficulties as the Banshee closes in on its enemy, and a Magna Mk I Small Laser mounted in its head appears to have been installed as an afterthought. Sixteen heat sinks help keep the 'Mech cool though, and thanks to its prodigious size the Banshee can turn lighter 'Mechs to scrap in hand-to-hand fighting.",
  "history": "The Hegemony soldiered on though, producing five thousand Banshees in a decade before its poor combat performance finally forced them to stop production in 2455 and the 'Mech was relegated to training and militia units for the next few centuries. Even during the Succession Wars the 'Mech's poor reputation meant many commanders saw it as a liability rather than an asset; unless they were fighting on a backwater Periphery world or as part of a poorly-equipped outfit, most Banshees were placed in second-line reserves to provide fire support or fulfill the role of brawlers so that better-armed 'Mechs need not engage in hand-to-hand combat. In this way fully a third of the original Banshee production run remained operational by the dawn of the thirty-first century and could be found throughout the Inner Sphere and Periphery, with the lion's share residing within the Lyran Commonwealth. Though a few attempts had been made over the years to improve the Banshee, Defiance Industries was the first to produce a variant which markedly improved on the original and was suggested by many of its original critics. With help from the Federated Suns and access to blueprints from the original Hesperus II factories, the BNC-3S proved to be such a success the Lyrans began fielding them in front line units, surprising their enemies who ignored them to focus on \"real\" threats with thoroughly unexpected firepower. Under the Federated Commonwealth improvements would continue to be made, though not at the same priority level as other projects, and the much-improved BNC-5S was active in time to meet the Clan Invasion.",
  "manufacturer": [
    "Diplass BattleMechs",
    "Witten Industries",
    "Defiance Industries",
    "Star League Weapons Research"
  ],
  "primaryfactory": [
    "Apollo",
    "Hesperus II",
    "Hesperus II",
    "New Earth"
  ],
  "systemmanufacturer": {
    "chassis": "Star League",
    "engine": "GM",
    "armor": "Starshield",
    "communications": "Dalban",
    "targeting": "Dalban"
  },
  "systemmode": {
    "chassis": "XT",
    "engine": "380",
    "communications": "Commline",
    "targeting": "HiRez-B"
  }
}

I created a new section fluff that contains all the additional information that is usually not required for playing or creating record sheets. As you can see, the MTF keys systemmanufacturer and systemmode can appear multiple times in an MTF file and contain a "subkey" (i.e. a nested key:value pair within the value). I tried to separate all these "subkeys" into individual key:value pairs and organize them neatly. Also, the manufacturer and primaryfactory values are always lists, since they often contain multiple values.

Installation

PyPi

pip install mtf2json

Manual

Clone the repository and install the dependencies:

git clone https://github.com/juk0de/mtf2json.git
cd mtf2json
pip install .

Usage

CLI

To convert an MTF file to JSON, use the following command:

mtf2json --mtf-file <path_to_mtf_file> [--convert] [--json-file <path_to_json_file]

To query JSON data in the terminal (e.g. armor pips), pipe the output into jq:

mtf2json --mtf-file <path_to_mtf_file> | jq .armor.pips

Library

from mtf2json import read_mtf
from pathlib import Path
json_data = read_mtf(Path('/my/file.mtf'))

Development

• Install poetry
• Clone repository and cd into it
• Execute poetry install
• To run tests, execute poetry run pytest
• To run mtf2json, execute poetry run mtf2json

License

All source code of this project is licensed under the MIT License. The included MTF files (used for testing) are part of the MegaMeklab project und thus are licensed under the GPLv2 license (see https://github.com/MegaMek/#current-project-status).