ZDoom CL

ZDoom CL, also known as ZDoom Classic is a of the ZDoom source port by drfrag. It is based off ZDoom 2.1.4 (later 2.1.7). It focuses on enhancing the legacy codebase with new era specific features and enhancements whilst maintaining compatibility with old processors such as the and.

History
ZDoom CL was released to bring new features to very old hardware, allowing users to play mods for ZDoom up to the year 2006 or so. Starting from version 2.1.4a GL, a OpenGL renderer was added, built out of a recreated GZDoom 1.0.18 renderer which got backported to GZDoom 1.0.17, resulting in GZDoom 1.0.17a. ZDoom CL at this released in both software rendered and OpenGL based versions, with the latest release being on January 26, 2019.

Legacy
A year later, on March 8, 2020, drfrag made another ZDoom CL release. Instead of being based off ZDoom 2.1.4, this build was based off ZDoom 2.1.7 and had a different scope than the previous versions. The OpenGL renderer was dropped, making this version of ZDoom CL run purely in software.

Features

 * All features from ZDoom 2.1.4 (ACS, etc) and GZDoom 1.0.17a (recreated GZDoom 1.0.18 renderer backported to 1.0.17)
 * Various patches, ZDoom CL is the equivalent of ZDoom 2.2 in terms of feature set
 * OpenGL 1.1 based renderer (2.1.4a GL)
 * Includes sprite billboard options from GZDoom 1.0.31
 * Compiled with Pentium architecture optimizations
 * Sprite and wall distance culling to improve performance
 * Low detail modes (from ZDoom LE) (3x2, 4x4)
 * Quad horizontally and double vertically render modes (From ZDoom LE)
 * Options to switch between and  rendering (Worldsim, backend)
 * Pixel doubled and quadrupled low resolution DirectDraw modes (from ZDoom 2.3) for more recent Windows versions
 * Modernized keyboard layout
 * Support for older versions of DeHacked patches

ZDoom CL 2.1.8 features

 * All features from ZDoom 2.1.7 (ACS, etc)
 * Sprite and wall distance culling to improve performance
 * Includes a Direct3D/DirectDraw backend
 * Ability to run older mods in PK3 format

Trivia

 * ZDoom CL requires the following: 486 DX4-100, 16 MB RAM, 1 MB card and Windows 95. For OpenGL mode a graphics card with GL 1.1 support is required.
 * Previous versions include 2.1.4a CL, 2.1.4a CL R2, 2.1.4a GL, 2.1.4a GL R2.1.