1. What is this?

2. Why it's developed?

3. Features

4. Supported platforms

5. Configuration and autoexec files

6. Installation and running

7. Compiling

8. Licensing

9. Credits

10. What is this?

OpenTomb is an open-source engine reimplementation project intended to play levels from all classic-era Tomb Raider games (TR 1—5) and custom TRLE levels. The project does not use any old Tomb Raider source code, because all attempts to retrieve sources from Eidos / Core were in vain.

Instead, everything is being developed completely from scratch. However, OpenTomb uses certain legacy routines from such unfinished open-source projects as OpenRaider and VT project (found at icculus.org), plus it incorporates some code from Quake Tenebrae.

All in all, OpenTomb tries to recreate original Tomb Raider games experience, although with contemporary updates, features and additions — to fully benefit from being running on modern PCs with powerful CPUs and graphic cards — unlike original engines, which are getting older and older (original engine, on which all classics were based, will turn 20 next year).

2. Why it's developed?

Many may ask — why develop another TR engine clone, while we have fully working Windows builds of TR2-5, and TR1 is perfectly working through DosBox? The answer is simple - the older engine gets, less chance it'll become compatible with further systems; but in case of OpenTomb, you can port it to any platform you wish.

Other people may ask — why we're developing it, if there are already patchers for existing engines, like TREP, TRNG, etc.? The answer is simple — no matter how advanced your patcher is, you are limited by original binary — no new features, no graphic enhancements, no new structures and functions. You are not that limited with open-source engine.

3. Features

• OpenTomb has completely different collision approach. Engine uses special terrain generator to make every room's optimized collisional mesh from so-called "floordata", which was a significant limiting factor in originals.
• OpenTomb does not run at fixed 30 FPS speed, as any old engine did. Instead, variable FPS rate is implemented, just like in any contemporary PC game.
• OpenTomb uses common and flexible libraries, like OpenGL, OpenAL, SDL and Bullet Physics.
• Lua scripting is a key gameplay feature in OpenTomb, as all entity functionality is not hardcoded, as it was in classic engines, but moved into plain-text files, which can be modified and extended any time.
• Many abandoned and unused features from originals were enabled in OpenTomb. New animations, unused items, hidden PSX-specific structures inside level files, and so on! Also, original functionality is being drastically extended, while preserving original gameplay pipeline.

4. Supported platforms

OpenTomb is a cross-platform engine — currently, you can run it on Windows, Mac or Linux. No mobile implementations are made yet, but they are fully possible.

5. Configuration and autoexec files

Currently, all settings in OpenTomb are managed through configuration and autoexec files. Configuration file contains persistent engine and game settings, while autoexec contains any commands which should be executed on engine start-up.

Configuration file (config.lua) is divided into different sections: screen, audio, render, controls, console and system. In each of these sections, you can change numerous parameters, which names are usually intuitive to understand.
Autoexec file (autoexec.lua) is a simple command file which is executed at engine start-up, just like you type them in the console. Basically, you shouldn't remove any existing commands from autoexec, as most likely engine won't start properly then, but you can modify these commands or add new ones — like changing start-up level by modifying setgamef() command.

6. Installation and running

You don't need to install OpenTomb, but you need all classic TR game resources. Problem is, these resources (except level files themselves) are tend to be in some cryptic formats or incompatible across game versions. Because of this, you need to convert some game resources by yourself or get them from somewhere on the Net. Anyway, here is the list of all needed assets and where to get them:

• Data folders from each game. Get them from your retail game CDs or Steam/GOG bundles. Just take data folder from each game's folder, and put it into corresponding /data/tr*/ folder.

• CD audio tracks. OpenTomb only supports OGG audiotracks for a moment, so you should convert original soundtracks by yourself, or just download whole TR1-5 music package here: http://trep.trlevel.de/opentomb/files/tr_soundtracks_for_opentomb.zip
  PLEASE NOTE: script file bundled in this archive is outdated, so don't overwrite existing soundtrack.lua file with one provided in archive.

• Loading screens for TR1-3 and TR5. For TR3, get them from pix directory of your installed official game. Just put this pix directory into /data/tr3/ folder. As for other games, it's a bit tricky to get loading screens, as there were no loading screens for PC versions TR1-2, TR4 used level screenshots as loading screens, and TR5 used encrypted format to store all loading graphics. So, to ease your life, you can simply download loading screen package here: http://trep.trlevel.de/temp/loading_screens.zip
  Just put it right into OpenTomb directory, and that should do the trick. Note: engine supports png and pcx format of screen images.

7. Compiling

There is a CMakeLists.txt file provided with source code, so you can compile OpenTomb using CMake. On Windows, you can also compile it from Code::Blocks IDE (project file is also provided). Alternatively, you can manually compile it in Code::Blocks by recursively adding all source files from /src directory, and adding these libraries in Linker Settings under Project Build options:

• libmingw32.a
• libSDL2main.a
• libSDL2.dll.a
• liblua.a
• libpng.a
• libz.a
• libpthread.a

On Linux, just download the source code and run in terminal:

cmake . && make

Necessary dependencies are development headers for SDL2, png, LUA 5.2, ZLIB. You can install them in Ubuntu-based distro with this command:

sudo apt-get install libsdl2-dev libpng12-dev liblua5.2-dev libglu1-mesa-dev zlib1g-dev

On Mac, use XCode project, which is also available in source code.

NB: Please note that OpenTomb requires C++11 (-std=c++11) flag to compile properly! You may use CPU-specific optimization flags (-march=prescott, -march=i486, -march=core2), as well as general optimization flags (-O1 and -O2), but DON'T USE -O3 flag, as Bullet tends to crash with this optimization level (GCC 5.1+ may compile it without errors).

8. Licensing

OpenTomb is an open-source engine distributed under LGPLv3 license, which means that ANY part of the source code must be open-source as well. Hence, all used libraries and bundled resources must be open-source with GPL-compatible licenses. Here is the list of used libraries and resources and their licenses:

• OpenGL — does not need licensing (http://opengl3.org/about/licensing/)

• OpenAL Soft — LGPL

• SDL / SDL Image — zlib

• Bullet — zlib

• Freetype2 — GPL

• Lua — MIT

• Droid Sans Mono, Roboto Condensed Regular and Roboto Regular fonts — Apache

9. Credits

NB: Please note that authors and contributors list is constantly extending, as there is more and more people involved in project development, so someone may be missing from this list!

• TeslaRus: main developer.
• Cochrane: renderer rewrites and optimizing, Mac OS X support.
• Gh0stBlade: renderer add-ons, shader port, gameflow implementation, state control fix-ups, camera and AI programming.
• Lwmte: state and scripting fix-ups, controls, GUI and audio modules, trigger and entity system rewrites.
• Nickotte: interface programming, ring inventory implementation, camera fix-ups.
• pmatulka: Linux port and testing.
• Richard_trle: Github migration, Github repo maintenance, website design.
• Saracen: room and static mesh lighting.
• T4Larson: general stability patches and bugfixing.
• vobject: nightly builds, maintaining general compiler compatibility.
• vvs: testing, feedback, bug report.
• xproger: documentation updates.

Additional contributions from: Ado Croft (extensive testing), E. Popov (TRN caustics shader port), godmodder (general help), jack9267 (vt loader optimization), meta2tr (testing and bugtracking), shabtronic (renderer fix-ups), Tonttu (console patch) and xythobuz (additional Mac compatibility patches).

Translations by: Joey79100 (French), Nickotte (Italian), Lwmte (Russian), SuiKaze Raider (Spanish).