Gran Turismo 4 Prologue

Contents:

Deinterlace patch

Last update: October 9, 2021

A code disabling interlacing in the game, resulting in a sharper image.

For this code to function correctly in PCSX2, disable any deinterlace filters in the emulator!

Setup instructions


PAL

NTSC-J

See source on GitHub

Remappable controls

Last update: October 9, 2021

Gran Turismo 4 Prologue, despite being a (somewhat) full release, does not feature control remapping. The game internally loads and saves mappings, but no menus exist, leaving the feature unused.

With this code, I “exposed” mappings to the PNACH file, so users may freely map controls however they wish. By default, the code ships with stock mappings, so make sure to modify the code to your needs.

Please remember to read the instructions included in the PNACH file and adjust the code to your preferences!

Setup instructions


PAL

NTSC-J

See source on GitHub

Adjustable units

Last update: October 9, 2021

We had to wait until Gran Turismo 4 to have a proper measurement units selection menu in the game. Before that units were locked to the specific game version, most notably locking NTSC-U versions of the games to use imperial units. While in Gran Turismo 1 and 2 units were fully hardcoded, turns out Gran Turismo 3 and later include code handling multiple speed, power, and torque units, although they are predetermined by the user’s choice of language.

With these codes, measurement units may be freely picked, just like in Gran Turismo 4. Whether it means using metric units in the NTSC-U versions, or imperial in PAL versions, the cheat code can be modified to force any selection of such.

Available units:

  • Speed and distance:
    • 0 - KMH/KM
    • 1 - MPH/Miles
  • Power:
    • 0 - PS
    • 1 - HP
    • 2 - BHP
    • 3 - CV
    • 4 - kW
    • 5 - PF
  • Torque:
    • 0 - kgf.m
    • 1 - ft.lb
    • 2 - NM

Setup instructions


PAL

NTSC-J

See source on GitHub

Adjusted triggers sensitivity

Last update: March 4, 2023

Patch further improved by Aero_.

Since Gran Turismo games have always offered full control remapping, it’s possible to utilize triggers on modern controllers for throttle/brake, much like most modern games do. However, unlike in newer Gran Turismos, doing this in the PS2 games results in a mediocre experience – analog sensitivity is tailored for analog buttons of the DualShock 2 controller, and therefore inputs are heavily scaled. In practice, this means that anything over ~half the trigger press is already registered as a 100% input, so precise throttle control is hard. With this code, I’ve removed this scaling as much as reasonably possible, so now 100% input registers from a near full press of the trigger, therefore making the experience closer to how the later Gran Turismo games handle it.

Setup instructions


PAL

NTSC-J

See source on GitHub

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