GT4Recomp 1.3.0-rc13 (test build)

A test release candidate of 1.3.0: a 360-degree chase camera on the right stick, CoreGS 2.0 fixes for photo mode, the
Nordschleife fences and the used-car showroom, your own texture folder, and fixes players asked for on GitHub. The race itself
is unchanged.

Highlights

• 360-degree chase camera (both games, on by default): in the chase view, the right stick's left and right turn the camera
  round the car, smoothly, and it swings back when you let go.
• CoreGS 2.0: photo mode no longer flickers to black every other frame, the Nordschleife's far fences are see-through mesh
  again, and the used-car showroom no longer stutters while the car turns.
• Your own texture folder: point the launcher at the folder your texture packs already live in (for example PCSX2's).
• Fixes from GitHub: PCSX2 card import, deleting the active save, ReShade's Home key with GSdx, GSdx in a OneDrive Documents
  folder, less crackling on Proton and Steam Deck, and a way to install GSdx by hand when its download fails.

New

• 360-degree chase camera (TASK-159). The game's chase camera follows the car with a spring on its turn; the right stick X
  adds an angle to the camera's turn just before the game computes that spring, so the camera swings round the car the game's
  own way and comes back when the stick returns. With the stick at rest nothing changes at all. While the camera is on, the right
  stick Y is no longer the analog throttle and brake (the game's default controller setup puts them there, so a sideways push
  that is not perfectly level would also accelerate or brake). The triggers keep working: they are the R2 and L2 pressure
  buttons. To turn the camera off: camera_360=0 in game.ini for a direct start (a launcher switch comes later). The stick is
  read from the game's own pad buffer, so recorded drives replay the camera. The idea and call site come from the community
  "360 Degree Chase Camera" patches by Vyerq/unko_ (v2.00) and Nenkai's port from Duchi/Vyerq (Spec II); no patch words are used:
  the change is our own, at the translated call site.
• Choose the custom textures folder (TASK-157, issue #95). Settings > Graphics now lets you pick the folder the texture
  packs are read from, with no copy; the compiled shaders then go to the data folder, never beside your folder.
• Delete the active save (TASK-153, issue #98). The Saves page can delete the save in use; it no longer comes back at the
  next Play. It is moved to the Recycle Bin, and a copy of the card it came from is kept as *-before-delete.ps2.
• Install GSdx by hand (TASK-158, issue #139). When the GSdx download fails, the dialog offers Try again and Install from a
  file: a gt4-gs-<version>-windows-x64.zip you downloaded elsewhere, checked against the SHA-256 of that release's
  SHA256SUMS exactly as a download is.

Fixes

• Photo mode flickered to black every other frame on CoreGS 2.0 (TASK-151). Photo mode shows two 640 x 448 buffers in
  turn, and the first shares its address with a wider, empty buffer an earlier screen left. The display took that one on every
  other picture. It now takes the buffer of the display's own width first. Photo mode then holds 59 to 60 FPS on an RTX 3060
  laptop at 6x.
• The Nordschleife's far fences showed as a dark band on CoreGS 2.0 (TASK-149). A texture upload over a mip level now draws
  the pending batch first, so the fences keep their own smaller levels.
• The used-car showroom stuttered while the car turned on CoreGS 2.0 (TASK-150). Every second frame the game uploads the
  studio backdrop over the memory of the picture it just drew, and the renderer read that picture back from the graphics card
  first, a wait of 4 to 6 ms. The upload is now merged on the graphics card block by block, with the same pixels and no wait.
  On an RTX 3060 laptop at 6x the waiting fell from 1.6 to 0.03 ms per frame, 60 FPS in every run.
• PCSX2 memory cards whose saves sit near the end of the card failed to import (TASK-152, issue #86). The allocation chain
  is now checked against the card's real capacity.
• ReShade's Home key did nothing with GSdx (TASK-154, issue #102). The game window passes Home, End, Insert, Delete, Page Up,
  Page Down and Scroll Lock on to the GSdx window.
• GSdx did not start when the Documents folder is in OneDrive (TASK-155, issue #131). GSdx now keeps its settings beside its
  own executable (portable.ini).
• Crackling sound on Proton and Steam Deck (TASK-156, issue #129). Under Wine the game uses larger audio buffers.
  GT4_AUDIO_LATENCY_MS (20 to 500) sets the latency by hand.

Known issues

• Photo mode on slower graphics cards (CoreGS 2.0): each picture still waits for the graphics card twice (a palette and the
  camera's focus reading), so frame times can be uneven. Planned as TASK-162.
• 360 camera: while it is on, the right stick Y no longer works as analog throttle and brake; in split screen both chase
  cameras follow player 1's stick (as the community patch); the launcher has no switch for it yet.

The same game

Against rc12, on this build (both games built again with a fresh profile, from the camera's hooked units):

• Physics: the race clock at every VBlank and the whole simulation state, byte for byte, on three recorded laps (George V Paris,
  El Capitan, Tokyo R246) and on the v2.00 night race with 5 AI cars.
• Frames: every compared frame identical: 35 of 35 on each of three Spec II laps at 1x, 12 of 12 on a lap at 6x, 10 of 10 on
  the v2.00 night race at 3x and 14 of 14 on the v2.00 Arcade path.
• Checks while running, against the exact interpreter: 236,448 VU1 samples on Spec II and 355,388 on v2.00, and the MTVU check
  over 8,032 frames, all with 0 differences.
• The 360 camera changes nothing while the right stick rests (none of these recordings moves it); the race clock stays the
  same when it moves, since only the camera's own values change.
• On an RTX 3060 laptop (3440 x 1440, CoreGS 2.0 at 6x, the launcher's settings) this build ran the used-car showroom at 60.0
  FPS in both runs (frame time deviation 0.12-0.15 ms) and photo mode at 60.0 and 59.4 FPS.

Thanks

• Luan Antony, whose pull requests the PCSX2 card, save deletion, ReShade, OneDrive, Proton audio, textures folder and GSdx
  fixes were re-done from (with him as co-author).
• The players who reported them: Dizzee112 (#86), FLoCkeYE (#98), utplayer01 (#102), telmocamargo (#131),
  Riveir (#129), xraynet (#95) and MarceloLima36 (#139).
• Vyerq/unko_, Duchi and Nenkai, whose 360-degree chase camera patches for PCSX2 gave the idea and the call site.

Install or update

• From rc8 to rc12 or another 1.3.0 test build: the launcher offers rc13 on the Beta channel (Settings > General).
• Installer: run GT4Recomp-Setup-1.3.0-rc13.exe. It keeps existing settings, saves and replays.
• Portable: unpack GT4Recomp-1.3.0-rc13-portable.zip anywhere. Settings, saves and data stay inside the folder.
• After the update, Play may compile CoreGS 2.0's shaders once, as after every update.
• Disc images: you need your own: Gran Turismo 4 (USA, v2.00), and your own Spec II 1.10 image for the mod. GT4Recomp ships no
  copyrighted game files.

Requirements

Windows 10 or 11, 64-bit, a processor with SSE4.1. CoreGS 2.0 needs a graphics card with Vulkan 1.2.

Credits and legal

Our code is MIT. GSdx is the PCSX2 GS (GPL-3.0-or-later), downloaded by the launcher and run in its own process; the game
executable contains no GPL code. FSR1 sharpening is written from AMD's published MIT design.