


Ranma 1/2: Chougi Ranbu Hen big framerate improvement and collision bug fix Hack V1.4
by Upsilandre

You can contact me on my Twitter @upsilandre or upsilandre@Gmail.com or YouTube.


It is an IPS patch to be applied to the original ROM with software such as Lunar IPS.
The exact reference of the original ROM (No-Intro):
Ranma 1-2 - Chougi Ranbu Hen (Japan)
File/ROM SHA-1: 3754284F915C5E7281E1412B932B7BA876F05348
File/ROM CRC32: C552B1F

This patch (since version 1.3) is compatible with the Dynamic-Design's translation patch V1.10 but it must be applied before the translation patch (translation patch causes visual glitches on the menu, Herb boss, female Ranma and Kuno if you combine it with the wrong versions of my framerate patch).


I made a comparison video with visualization of performance (framerate and CPU consumption):
https://youtu.be/k-fJ4srsem8?si=VRSWGjc5JqTDD-Xg
You will always find the latest version of the patch under this youtube video (easier to find).


Ranma 1/2: Chougi Ranbu Hen is a good fighting game close to SF2 but with one big flaw: Its framerate is catastrophic. The game is calibrated for 60 fps but can never reach it even if you don't touch the controller and leave the fighters idling. It varies continuously between 30 and 50 fps. With the way games used to work, this means that Ranma runs in slow motion all the time.
The other consequences are a degraded input lag and that the game also has very bad frame pacing because the duration of the frames themselves is very variable. It can vary from 1 to 4.

The hack consists on optimizing the code of the most expensive tasks (this is not a SA1 or FastROM hack). This goes from sprite management to collision management, including input management and sound effects, plus a few other little things.
The result is a game that now runs with a rock stable 60 fps framerate. This means that the game's frames are now updated with every screen scan even in the most intense situations whereas in the original game some frames required up to 4 scans before being updated.
There is no longer any frame drop. It completely changes the pacing of the game. The input lag is also improved and the frame pacing is now perfect.
Another fun side effect is that the timer now runs at the correct speed (99 seconds is exactly 99 seconds now, unlike the original game. This gives away that this is the correct speed for the game).


But this is not just a framerate improvement patch. It's a kind of double patch that also fixes a lot of collision bugs from the original game to have a cleaner game. I detail all the collision changes in this google doc for pro players of the game who would like to know exactly what changes on this subject:
https://docs.google.com/document/d/1Wg0esR4RL_hHugeFbNfxss_SGwdhtSh_mpseoLZyLyo/edit?usp=drive_link



Update history:
27 August 2024  Version 1.4: Fixes more collision bugs from the original game and slightly adjusts the speed of idle animations
06 August 2024  Version 1.3: Now compatible with translation patch
02 August 2024  Version 1.2: Improves SFX check
31 July   2024  Version 1.1: Fixes a bug that causes the game to crash
28 July   2024  Version 1.0: Base



