Changelog 1.7.1

Note

The Remix Runtime is now a separate download because certain files got too large for GitHub

The game is now rendered through the Remix API

This is the big one. Until now, Remix had to catch every single draw call the game makes and rebuild the scene from them, and GTA IV issues a lot of draw calls. That's why the mod was largely CPU-bound in denser parts of the city and that's also why draw distance was limited.

The compatibility mod now builds Remix meshes straight from the game's own geometry data and hands them to the runtime through the Remix API, bypassing the D3D9 path almost entirely. This allows for larger draw distances while also improving the performance if you have a beefy enough GPU. Remember, this is still fully path-traced at the end of the day.

The custom Remix runtime and bridge received a lot of performance and logic improvements to make this possible.
I want to thank and highlight RemixPlus / Sparkles here, because a lot of these improvements came from them.

The runtime this mod ships with is now fully based on a heavily modified version of RemixPlus.
Please consider supporting them on Patreon or on Ko-Fi!

The runtime now also features the official DLSS 5 implementation from Nvidia (with the option of multiple passes by RemixPlus).

New water

Water is now drawn through the API as well, which made a proper rework possible.
The tessellated wave area around the camera is now much larger, with procedural waves continuing the simulation.
The runtime got a new shoreline system: water fades out softly where it gets shallow or meets objects,
which removes the bright seam and hard edge along every coast.

Wetness 2.0

The world got a new physically motivated wetness model. It now forms puddles where water would actually pool:
dips in intersections, potholes etc. Puddles grow as it keeps raining and dry from the edges outward.
They get wind ripples and raindrop impacts and everything stays wet for a longer period after the rain stopped until it slowly dries.

The best thing about it? It performs A LOT better than the older system, freeing up some of your GPU resources for other tasks.
Rain particles are now fully handled by RemixPlus, look way better and no longer reach interiors.

Atmosphere and Fog

The Numos atmosphere system by RemixPlus / Sparkles received a lot of love since the version that shipped with the previous CompMod (with additional changes from me). Listing them all would take too long, but here are a few screenshots that should speak for themselves:

Aerial perspective (by RemixPlus) now hands off correctly to the volumetric fog which allows both systems to exist next to each other.
This gives us great looking sunrises and sunsets without having to rely on Remix' volumetrics system. Weather presets are now separate config files and can easily be edited by anyone.

Distant Lights / Vehicle Imposters

Nights were looking quite dull, especially with the limited draw distance we had to live with.
Due to the new way of rendering, it was possible to get the fake distant street light sprites to work.
Vehicle imposters that were previously stretching all over the screen (and thus disabled for prior releases) now also work as expected, making the night scenery feel more alive.

Blood on Peds

That one was quite tricky but it fully works now.

HDR Support, new DLSS5 Model and other noteworthy stuff

HDR support by TheGreatHMMMM (Alt HDR10 tonemapper) + added HDR support for the default Psycho17 tonemapper
Latest official DLSS5 model
Improvements to the existing AutoExposure logic
Dynamic vehicle headlights should look a lot better now
Improved visuals on very distant trees (lowest LOD)

Installer / AutoPBR

If you've used the AutoPBR mod on older versions, you know that it can take quite a while to load all of the replacements.
With the usage of RTXIO (a packaging and compression tech by NV), size and load times were drastically reduced (to mere seconds) and it even reduced hitching. This is fully optional. It unfortunately requires a little bit manual work on your side but the installer will walk you through the process.

Full Changelog 🍓 (Click Here to Expand)

Rendering and performance

Static map geometry, dynamic entities, sorted alpha entities and area-light renders are drawn through the Remix API
Peds are drawn as skinned API meshes (bone palette per draw), including blendshape heads and hair
(heads can not be replaced via remix replacements because of blendshape usage)
Vehicles are drawn through the API with damage deformation, vertex colors, dirt and livery textures; tyres and flat tyres included
(remix replacements would break when a vehicle takes damage as deformation is done on the cpu)
The game's "vehicle imposters" (fake distant cars and street light / aircraft sprites) are drawn through the API
The engine's pass setup (render states, shader constants, textures) is skipped for geometry the API path owns
API meshes keep the D3D9 geometry hashes, so existing USD mesh and material replacements apply unchanged
Per-draw data (texture categories, wetness, emissive scale, hash overrides, UV animation) reaches the runtime through a new API extension, so API draws look exactly like the D3D9 draws they replace
Runtime: skinning runs on the GPU for all meshes
Runtime: animated and skinned meshes get their own acceleration structures
Runtime: the queued command buffer limit is configurable and raised, fixing a loop where CPU and GPU serialized and the GPU sat partially idle
Runtime: fixed sampler feedback streaming replacement textures several mip levels too low (blurry normal / roughness maps on partial replacements)
Bridge: fixed skinned mesh serialization, camera forwarding and the mesh extension handling
New 2-core and 4-core processor affinity batch files with SMT support
Fixed-function fallback path remains available and switchable per category
Instances for the static world are retained and only updated via the API when they actually changed.
Reduces bridge traffic and improving performance
Runtime: New CardNormals instance category to make distant tree cards (LOD) look nicer

Water

Water surface drawn through the Remix API
Tessellated water radius raised to 300 units with ring-based LOD (2 / 4 / 8 unit cells)
Procedural far waves continue the game's 100 x 100 cell simulation outward, following its amplitude, wind direction and length
Runtime: shoreline fade based on water depth
Runtime: open water without a sea floor below no longer renders lighter and hazier than water over a floor
Water presets: Performance / Standard / Quality / Insane
Water seabed marker disabled, water texture scale and block scan distance tuned

Weather and wetness

Runtime: new layered wetness model with a per-frame rain map (ground height, depression, slope, rain cover) around the camera
Puddles form in depressions, stop at curbs, grow with the rain and dry from the edges
Rain shadow under roofs and bridges with soft edges; cars, benches and street furniture do not cast rain shadow
Wind ripples on puddles, raindrop impacts (stronger inside puddles), wet albedo darkening and saturation by porosity
Wetness is held after the rain stops and fades out slowly, never wetter than the rain peak
Ripple strength scales with the game's wetness
Wetness now scales properly on vehicles
Wetness is evaluated at full detail only on primary rays, which makes rain much cheaper than before
Wetness presets (standard / high with more puddles) and all rtx.wet.* options exposed
The game's original rain particle system is disabled by default (RemixPlus precipitation is used instead)

Sky, fog and atmosphere

Aerial perspective hands off at the actual (weather preset) froxel range instead of the authored one
The sun can leave the froxel volumetrics to the aerial perspective (sunVolumetricScale), restoring city haze and sun shafts
The fog's sun weight no longer dims particles and decals
Particles beyond the fog range are no longer dark sprites against the distance haze
Lightning flashes no longer leave a slowly fading trail in the fog
Rain drops are lit by the sky again (Sky Light setting works) and are correctly kept in front of the sky
Precipitation no longer falls through ceilings
Weather preset editor: "Sky in Fog" controls added, Fog Density slider fixed
Star magnitude limit slider fixed
Fixed moon elevation / rotation variables

Visuals and settings

Rendering settings reorganized into tabs: General, Remix API, Water, Vehicles, Foliage / Hair
New Remix API tab with switches for statics, peds, vehicles, water and the mesh cache
Rain toggle moved to the Weather tab, wetness settings exposed in the Weather tab
Bloom: new minimum intensity and threshold (day) settings and general tweaks
Reduced light intensity on vehicle sirens
Emissive: option to allow vertex colors on emissive alpha
Fixed inner / outer cone light overrides in the menu
Increased slider limits, options missing from rtx.conf are created from defaults
Removed the unused decal dirt shader settings
Performance logger x/y offset and other small tweaks
Updated dxvk.conf and bridge.conf
ImGui renders through an 8-bit target while Windows HDR is on
DLSS 5 Neural Rendering follows the new DLSS NR / DLFG Lite update

Fixes

Fixed multiple game freezing issues
Remove baked game lighting from lit particle effects (fixes explosion colors)
Hardened an already existing crash fix (TLAD: Shifting Weight) #167
Fixed crashes when alt-tabbing or minimizing while the game was mid-frame
Fixed crashes when capturing scenes containing skinned API meshes
Fixed HUD / menu scale after resolution changes
Sky auto detection disabled (it tagged decals as sky when nothing was drawn on D3D9 before them)

Other changes

Add tracy profiling (ReleaseTracy configuration)

Installer and distribution

Remix runtime ships as a separate zip next to the mod zip
Support for the packaged (RTXIO) AutoPBR version
Uses an installed git (2.28+) when available, MinGit otherwise
Clearer error messages when a zip is missing or versions mismatch

Installation:

Install using the installer:

Download GTAIV-Remix-CompatibilityMod-1.7.1.zip
Download GTAIV-Remix-RemixRuntime-1.7.1.zip
Download GTAIV-Remix-CompMod-Installer.exe
Place all three files in the same folder (no need to copy them to your game folder) and run GTAIV-Remix-CompMod-Installer.exe
Use the File Dialog to select your GTAIV.exe which is located in your GTAIV install folder
If this is your first time installing, the installer will ask if you want to install a custom Fork of FusionFix
- Press YES - If you already have FusionFix installed, it's definitely recommended to install this because the original, unmodified version has a few incompatibilities with RTX Remix. If you do not have FusionFix installed, you are free to choose. It's not a requirement but highly recommended.
The installer will ask you if you want to download the required base-remix-mod.
- Press YES - The CompMod will not function correctly without it - so make sure to install it.
- Use the GIT install method (recommended) because its easier and faster to update to new versions (and uses less bandwidth)
The installer will ask which version of the optional gta4-autopbr-mod you want to use.
- This mod converts a bunch of game materials to approximated PBR-materials and makes the game less plasticy. It is entirely optional.
- Packaged version (highly recommended, loads much faster): the installer opens a download page (Mega / Google Drive) and shows two steps:
  download GTAIV-AutoPBR-X.X.X.zip and extract it into your GTAIV folder (next to GTAIV.exe). The zip already contains rtx-remix/mods/z_gta4rtx_autopbr.
  To update later, re-run the installer, pick the packaged version again and compare the installed version it shows with the newest zip. Delete everything inside rtx-remix/mods/z_gta4rtx_autopbr before extracting a newer zip.
- GitHub version: loose files downloaded by the installer using the GIT/zip method chosen for the base mod. Slower to load.
Make sure that you remove all custom launch arguments for GTAIV in Steam (if you have any set and use Steam to run the game)

Tip

You can re-run the installer at any time and choose to only check for remix-base-mod or AutoPBR updates.
If you've used the GIT installation method, it will do delta updates and pull the latest changes.
The base mod (textures/meshes) is getting constant updates which are not coupled to Compatibility Mod releases.

OR Install manually (no need to do this if you've used the installer):

Download GTAIV-Remix-CompatibilityMod-1.7.1.zip
Download GTAIV-Remix-RemixRuntime-1.7.1.zip
Open the compatibility mod zip and extract all files contained inside the GTAIV-Remix-CompatibilityMod folder into your GTAIV directory (next to the GTAIV.exe). Overwrite all when prompted.
Open the remix runtime zip and extract its content (the .trex folder and the files next to it) into your GTAIV directory as well. Overwrite all when prompted.
If you want to use FusionFix or have it installed already, it's definitely recommended to install rtx-remix fork of it.
You can find the files inside _installer_options/FusionFix_RTXRemixFork. Extract the plugins & update into your GTAIV directory and override any existing files.
You may also want to use GTAIV.EFLC.FusionFix.cfg from either mode_fullscreen/plugins or mode_windowed/plugins.
Download gta4-rtx-base-mod
Extract the mods folder (inside of gta4-rtx-base-mod-master) into your rtx-remix folder so that the folder structure looks like this:

.  
├─ ...
├─ 📁 steamapps
│  └─📁 common
│     └─📁 Grand Theft Auto IV
│       └─📁 GTAIV
│         ├── 📜 a_gta4-rtx.asi
│         ├── 📜 d3d9.dll
│         ├── 📜 GTAIV.exe
│         ├── 📜 ...
│         │
│         ├── 📁 rtx_comp
│         └── 📁 rtx-remix
│             └─📁 mods
│               └─📁 gta4rtx
│                 ├── 📜 comp_cars.usda
│                 ├── 📜 comp_effects.usda
│                 ├── 📜 mod.usda
│                 └── ...
└── ...

Credits

NVIDIA - RTX Remix
People of the showcase discord - especially the nvidia engineers ✌️
Dear ImGui
imgui-blur-effect
minhook
toml11
Ultimate-ASI-Loader
miniz
Rapidjson
DiscordRPC
FusionFix
FusionShaders
Rage-Shader-Editor
IV-SDK
IV-SDK-DotNet
AssaultKifle47
DayL
Entity
Gabdeg
Hemry
Danlopand / Thundery_Dan
KapibosRU
Budgie
Alex from Digital Foundry
Sparkles (Remix Plus - Numos - Remix Optimization)
CR (Remix Plus)
TheGreatHMMMM (Remix Plus - HDR implementation)
Gokuwashere (Remix Plus)
All 🍓 Testers

Usage and general Info

Run the game like normal or use the provided batch files (mentioned in the Wiki further down) if you notice heavy stuttering.

Press Alt + X to open the Remix menu
Press F4 to open the Compatibility Mod menu

Help

Press F4 go open the Help section for links to helpful guides