OpenRCT2

OpenRCT2 is a recreation of RollerCoaster Tycoon 2 (RCT2) in open-source code, incorporating some features from the original RollerCoaster Tycoon (RCT1) that do not exist in other RollerCoaster Tycoon games, while also fixing some issues and improving upon some details in the official games, as well as adding a functional multiplayer feature that allows several players to co-build a single park.

OpenRCT2 is free software, licensed under the GNU General Public License v3.0.

Architecture

OpenRCT2 is an attempt to decompile RollerCoaster Tycoon 2 into C. RCT2 was originally written in MASM and Visual C++ where functions related to interfacing with the operating system were written in C (supposedly 1%), with the rest of the game being written in pure x86 assembly. OpenTTD, which is an open-source recreation of Transport Tycoon Deluxe was developed using a similar procedure—the original game was decompiled into C, which allowed for the addition of thousands of features to the game.

RCT2 uses the third version of Chris Sawyer's RollerCoaster Tycoon engine, which shares some code with Transport Tycoon. This is reflected in the usage of OpenTTD 0.1 code such as the windowing system and graphics rendering. While the version of the engine used in Chris Sawyer's Locomotion is newer than the one used in RCT2, OpenRCT2 uses RCT2's game engine to make the decompilation process easier.

In order to decompile the game gradually without introducing new bugs, every single procedure in RCT2 must be re-written individually in C. To test the accuracy of the re-written procedures, the decompiled C procedures are compiled into a DLL file (openrct2.dll) which exports an entry procedure mimicking the WinMain function in RCT2. The original executable rct2.exe has been patched so that openrct2.dll and WinMain are in the DLL import table and the WinMain export procedure in openrct2.dll is called at the start of the WinMain procedure in rct2.exebefore returning. With this system implemented, starting rct2.exe calls the new DLL as part of its initialization; the DLL can then run all the decompiled code whilst still being able to read / write to the rct2.exe memory model and run rct2.exe procedures.

The project therefore acts as a patch to RCT2, allowing each procedure to be gradually implemented while simultaneously adding new features where possible. Until all procedures of the original game are re-written in C, the project must remain a DLL which is called from the patched rct2.exe.

Features

OpenRCT2 adds several features that are not available in RCT1 and RCT2, including:

• Support for high resolution displays
• Window/Fullscreen toggle
• Incorporation of features unique to RCT1 within the RCT2 environment, such as:
  • Using the mountain tool during gameplay
  • The option to sort rides by track type (e.g. the Twister, Stand-Up Twister, Floorless and Hyper-Twister Roller Coasters are all re-categorised as Steel Twister Roller Coaster, with their individual vehicle types selectable from a built roller coaster's Vehicles tab)
  • Enabling both Powered Launch operating modes for all roller coaster types with the Powered Launch operating mode
  • Steep drop and flat-to-steep and steep-to-flat track pieces for the Junior Roller Coaster
  • Booster track piece for the Looping Roller Coaster, Corkscrew Roller Coaster and all Steel Twister Roller Coaster variants
• Improved guest path-finding AI
• Increasing the selectable region in landscaping tools to 64 tiles square
• Enabling the scatter tool for scenery objects during gameplay
• Enabling the "Have Fun!" objective in the Scenario Editor
• Custom menu screens
• A (graphically) customisable user interface
• Night Mode toggle (causes the game to periodically dim the park environment to simulate nighttime)
• An FPS counter
• Online multiplayer
• Multilingual translation
• Twitch TV integration (guests in a park are named as viewers in a Twitch TV stream)
• Hardware-accelerated graphics (on graphics cards that support hardware acceleration)
• A fully functioning 64-bit application
• A built-in cheat function, which enables such cheats as:
  • Construction while the game is paused
  • Lift/launch speeds up to 255 mph/410 kmh
  • Rides with 31 trains and/or 255 cars per train
  • Player-triggered guest generation
  • Extra cash
  • Forced Park Ratings
  • Ride renewal
  • Player-triggered ride breakdowns/fixes
  • Disabling of random ride breakdowns
  • Resetting of a ride's crash status
  • Changing the scenario objective to "Have Fun!"
  • Completing the scenario objective (including "Have Fun!")
  • Access to Scenario Editor options
• A built-in console that enables advanced features/cheats such as the editing of available objects

Development

This article or section is under construction. You can help by editing it! Relevant discussion may be available on this article's discussion page.

Development started on April 2nd, 2014 by Ted 'IntelOrca' John. Thanks to numerous contributions from others the OpenRCT2 project is making great progress and already has new features.

Currently, the windowing system, graphics rendering and basic game loop are being decompiled. Decompiling all of the game's procedures is a convenient way of identifying the game's memory structure. SDL2 has been used as a replacement for the operating system calls, allowing for cross-platform support after the dependency on the original game's executable has been removed.

As of 16th August 2014, various UI improvements have already been made, settings are now stored in a local INI file. More drawing functions have now been decompiled but still remain cryptic C, much of the game management have been decompiled (e.g. peep generation, awards, cash out) and almost half of the windows. A rough estimate based on number of functions in the original game and number of functions now in C tells us that the project is approximately 25% complete of its target goal of having the game run on 100% C code. More information can be found in changes to original game andwindow progress.

The aim is to completely decompile RollerCoaster Tycoon 2 into C so that cross-platform support, new features, and new gameplay can be added in a similar fashion to OpenTTD. With the addition of SDL2, the game can already be run in a resizeable window (which was not possible originally). Once the game has been fully decompiled, additional gameplay features, gameplay tweaks, and improvements can be introduced. The following is only a brief, non-exhaustive list of the possibilities - there are many more:

Distribution

As OpenRCT2 is free software, no payment is required to obtain a copy of it.

OpenRCT2 can be built on most modern computers, and this is the recommended method of obtaining the game. The source code for OpenRCT2 and instructions on how to build a copy of it are available on the OpenRCT2 GitHub Page.

Automated builds are also available from the official OpenRCT2 website's download page.

A separate program known as the OpenRCT2 Launcher also installs and automatically updates a copy of OpenRCT2, while featuring the ability to customise some OpenRCT2 settings that are not immediately visible, such as a customisable default window size.

Limitations and Known Issues

OpenRCT2 is not a standalone game and requires the official data files from RCT2 to function, although the original rct2.exe executable and, by extension, a working installation of RCT2, is not needed from OpenRCT2 0.0.5 onwards. In its current state, OpenRCT2 maintains full compatibility with any game saved in RCT2, and most games saved in OpenRCT2 can be loaded in RCT2 with few issues. For this reason, games saved in OpenRCT2 are subject to the same engine limitations in RCT2, such as:

• A maximum of:
  • 255 rides and shop/stalls in a park
  • 255 staff in a park
  • 1,000 guests in a queue line
  • 8,192 game years
  • 10,000 objects in a game
  • the same (seemingly variable) sign/banner limit

The above limitations in OpenRCT2 are expected to disappear if and when new file formats for scenarios, tracks and saved games are introduced at a later date, when OpenRCT2's feature set is completed.

Due to the architecture of OpenRCT2, very few additional issues exist in relation to its ability to open scenarios, tracks and saved games created in RCT2. However, as the feature set of OpenRCT2 is not complete, the addition of new features may cause unexpected glitches and/or problems during gameplay. The project's GitHub page has an issue tracker where known problems discovered by the developers and the community-at-large are raised for further action and ultimately resolved by its pool of contributors.

In New Media

OpenRCT2 was used by Vargskelethor Joel from Vinesauce to livestream footage of RollerCoaster Tycoon 2 from his Twitch TV channel on several occasions. A compilation of scenes from those livestreams can be viewed on his YouTube channel here and here; the full livestreams can be viewed on his alternate YouTube channel here.

Links

• Official Site
• Feature List
• Downloads Page
  • OpenRCT2 Launcher—installs and automatically updates OpenRCT2
• GitHub Page
• Facebook Wall
• Subreddit
• Screenshots of older builds of OpenRCT2, hosted on Imgur:
  • Cheat windows
  • Large land tool area
  • High resolution
  • Resizable window
• RCT2 Subreddit
• IntelOrca's website