Chocolate Doom

Work done by me

I am currently removing any occurrence of Hexen, Heretic and Strife from the compilation pipeline; for now, cocurrences of these three games will stay in the code and later removed since I care more about compilation speed than space occupied by code.

Compile and start the game

$ cd chocolate-doom
# Build
$ ./autogen.sh
$ make -j
$ sudo make install
# Play
$ ./start.sh

Notes taken from Sanglard's book

Where is main()?

Exploring a source code repository always starts with finding out what the OS will select as the entry point. 99% of the time it means finding the int main(int,char**) function.
In the case of DOOM there is one entry point per OS and they are all in implementation specific (I_*) files. For DOS it is in i_main.c.
Regardless of the platform, all entry points converge on the core main function named D_DoomMain located in d_main.c.

The game loop

src/doom/d_main.c/D_DoomLoop is the game loop where the machine runs as fast as possibile to update the game simulation according to user input and A.I. and then generate visual and audio output.

Prefixes

V_ is for Video, M_ is for Menu, Z_ is for Zone Memory Allocator, R_ is for Renderer, P_ is for gamePlay, I_ is for Implementation dependent, D_ is for main Doom, S_ is for Sound, HU_ is for HUD and ST_ is for STatus bar.

What I did

• commmented every reference to Hexen, Heretic and Strife both in the code and in the building pipeline

• make the doomguy jump

Some useful (or funny) resources

• Chocolate Doom project homepage

• Can it run Doom?

• It runs Doom

• Game engine black book Doom

Work done by community follows

Chocolate Doom aims to accurately reproduce the original DOS version of Doom and other games based on the Doom engine in a form that can be run on modern computers.

Originally, Chocolate Doom was only a Doom source port. The project now includes ports of Strife.

Chocolate Doom’s aims are:

• To always be 100% Free and Open Source software.
• Portability to as many different operating systems as possible.
• Accurate reproduction of the original DOS versions of the games, including bugs.
• Compatibility with the DOS demo, configuration and savegame files.
• To provide an accurate retro “feel” (display and input should behave the same).

More information about the philosophy and design behind Chocolate Doom can be found in the PHILOSOPHY file distributed with the source code.

Setting up gameplay

For instructions on how to set up Chocolate Doom for play, see the INSTALL file.

Configuration File

Chocolate Doom is compatible with the DOS Doom configuration file (normally named default.cfg). Existing configuration files for DOS Doom should therefore simply work out of the box. However, Chocolate Doom also provides some extra settings. These are stored in a separate file named chocolate-doom.cfg.

The configuration can be edited using the chocolate-setup tool.

Command line options

Chocolate Doom supports a number of command line parameters, including some extras that were not originally suported by the DOS versions. For binary distributions, see the CMDLINE file included with your download; more information is also available on the Chocolate Doom website.

Playing TCs

With Vanilla Doom there is no way to include sprites in PWAD files. Chocolate Doom’s ‘-file’ command line option behaves exactly the same as Vanilla Doom, and trying to play TCs by adding the WAD files using ‘-file’ will not work.

Many Total Conversions (TCs) are distributed as a PWAD file which must be merged into the main IWAD. Typically a copy of DEUSF.EXE is included which performs this merge. Chocolate Doom includes a new option, ‘-merge’, which will simulate this merge. Essentially, the WAD directory is merged in memory, removing the need to modify the IWAD on disk.

To play TCs using Chocolate Doom, run like this:

chocolate-doom -merge thetc.wad

Here are some examples:

chocolate-doom -merge batman.wad -deh batman.deh vbatman.deh  (Batman Doom)
chocolate-doom -merge aoddoom1.wad -deh aoddoom1.deh  (Army of Darkness Doom)

Other information

• Chocolate Doom includes a number of different options for music playback. See the README.Music file for more details.

• More information, including information about how to play various classic TCs, is available on the Chocolate Doom website:

  https://www.chocolate-doom.org/

  You are encouraged to sign up and contribute any useful information you may have regarding the port!

• Chocolate Doom is not perfect. Although it aims to accurately emulate and reproduce the DOS executables, some behavior can be very difficult to reproduce. Because of the nature of the project, you may also encounter Vanilla Doom bugs; these are intentionally present; see the NOT-BUGS file for more information.

  New bug reports can be submitted to the issue tracker on Github:

  https://github.com/chocolate-doom/chocolate-doom/issues

• Source code patches are welcome, but please follow the style guidelines - see the file named HACKING included with the source distribution.

• Chocolate Doom is distributed under the GNU GPL. See the COPYING file for more information.

• Please send any feedback, questions or suggestions to [email protected]. Thanks!