CRL

CRL is a continuation of the Chocorenderlimits source port originally developed by RestlessRodent.

Building upon the original, CRL introduces a range of new features, quality-of-life improvements, and technical refinements aimed at assisting mappers in creating vanilla-compatible maps. It also includes additional in-game modes for testing specific scenarios. The in-game menu, accessible via the grave/tilde key ~, allows quick access to various settings and features.

The core concept remains unchanged: CRL is a crash-prone source port that warns you instead of crashing. Rather than removing engine limits, it highlights them through visual and runtime cues to mimic real vanilla behavior as closely as possible. To preserve the original DOS executable’s behavior and look, no modifications have been made to the rendering code. Known bugs like Tutti-Frutti and Medusa are still present by design. However, Medusa is no longer critical and does not crash Windows-based executables.

CRL is not a limit-removing port, and therefore cannot load overly complex or oversized maps. It is intended strictly for vanilla-compatibility testing.

Several important code fragments were ported from International Doom, Crispy Doom and DOOM Retro.

You can follow the official development thread on the Doom World forum.

Features

Render Counters

These counters track rendering elements relevant to vanilla engine limits:

SPR. Number of sprites processed by the renderer. Not all of them may be visible on screen, but they are still drawn internally. This limit is overflow-safe.
SSG. Number of solid segments rendered. Exceeding the vanilla limit of 32 may cause a crash.
SEG. Number of wall segments rendered. Exceeding the vanilla limit of 256 will result in the Hall of Mirrors (HoM) effect.
PLN. Number of floor and ceiling visplanes rendered. Exceeding the vanilla limit of 128 may cause both HoM artifacts and engine crashes.
OPN. Number of openings rendered during BSP traversal and rendering.

Playstate Counters

These counters reflect gameplay-related elements that can lead to instability or crashes in the vanilla engine:

BRN. Number of Icon of Sin monster spawn targets. The vanilla limit is 32. Exceeding it significantly increases the risk of a crash, especially when multiple spawners are used. This counter is shown only if at least one spawn target exists on the map.
ANI. Number of lines with scrolling animations (line special 48). Vanilla crashes with the message "Too many scrolling wall linedefs" if the map contains 65 or more such lines.
BTN. Number of buttons pressed simultaneously. Exceeding the limit of 16 within a single second causes a crash with the message "P_StartButton: no button slots left!".
PLT. Number of active or in-stasis platforms. If more than 30 platforms are active at once, vanilla crashes with "P_AddActivePlat: no more plats!".

Game Modes

These optional modes are designed to assist with map testing and debugging:

Spectator mode. Detaches the camera from the player, allowing free movement throughout the level. Use movement keys for horizontal navigation and the mouse wheel to move vertically.
Freeze mode. Halts all in-game activity. Monsters, projectiles, and environmental hazards are paused. The player cannot take any damage while this mode is active.
Buddha mode. The player's health will never drop below 1, regardless of incoming damage.
No target mode. Monsters completely ignore the player — they will not react to sight or sound.
No momentum mode. Disables player momentum. As noted in the Doom source code: "Not really a cheat, just a debug aid."

New Cheat Codes

Typing any cheat code that begins with ID will momentarily freeze player movement. No movement input is registered during this brief pause — this applies both to standard Doom codes and custom ones listed below.

IDKA gives all keys only.
KILLEM Instantly kills all monsters in the level (sets their health to 0).
TNTEM explodes all monsters on level (puts them in an xdeath state).
FREEZE freezes the entire game world.
NOTARGET monsters will not react to the player, even after seeing or hearing them.
BUDDHA the player's health will never drop below 1, no matter the damage.
MDK instantly kills the monster currently in the player's line of sight.

Changes to Standard Doom Codes

IDDQD now also resurrects the player if dead.
IDFA and IDKFA now include the backpack, which is not granted by these codes in vanilla.

New Command-Line Parameters

CRL supports all standard Chocolate Doom parameters. The following additional options may be useful:

-console opens the console output window, which also displays game warnings.
-coop_spawns adds multiplayer monsters and pickups to single-player games.
-shorttics lowers turning resolution, emulating demo recording behavior.
-complevel N emulates a specific version of Doom. You can use either a number or a name:

Number	Name	Emulated engine
0	1.2	Doom v1.2
1	1.666	Doom v1.666
2	1.9	Doom v1.9
2	doom2	Doom v1.9
3	ultimate	Ultimate Doom
4	final	Final Doom
4	plutonia	Final Doom
4	tnt	Final Doom

Download

CRL Doom, version 1.9 (September 21, 2024)

CRL Heretic, version 1.0 (June 12, 2023)