GTA rendering hook
GTA rendering hook
Implements DirectX11 and Vulkan rendering API to GTA 3, GTA VC and GTA SA.
Currently there are 2 versions, one of which is broken(can't really build it anymore):
- Old one which implemented only DirectX11 and had a few features(only GTA SA)
- New one which at the moment runs only on RTX hardware and uses vk_nv_ray_tracing extension(to be replaced with KHR one
once it is implemented in release drivers)
We have discord server, come and help to improve it!
How it works?
TL;DR: Currently we have incomplete RW rendering backend implementation that communicates via shared memory to
incomplete rendering engine instance running rendering loop based on Vulkan API.
Long version:
- Game rendering engine code is partially redirected to shared memory task queue
- Task queue loads game assets to GPU memory, processes various requests like retrieving supported resolutions etc.
- One of the tasks prepares a frame to framebuffer based on uploaded scene data, each frame draw calls is uploaded to
64bit process via task queue.
- Separation between rendering and game code is done for several reasons:
- It allows to use newer drivers, and support raytracing extensions
- It allows to use more memory if needed
- Surprisingly it works faster!
- Rendering right now is basic, and very hacky:
- BLAS is built for each model instance being loaded by the game. For GTA 3 we load some sectors around the player
using original lod system.
- Animations are prepared by compute shaders and rebuilt every frame
- TLAS is rebuilt every frame
- Scene is loaded to GPU, contains all materials, textures, vertex/index buffers and transform data
- Lights are prepared using very basic tiled culling implementation
- Primary rays are traced to compute G-Buffers: Albedo, Normals, LinearDepth, Motion vectors and Material params
- AO rays are traced, temporally accumulated and blurred via bilateral blur with varying kernel(based on temporal
variance)
- Shading for sunlight and each point light inside a tile is generated, then temporally accumulated and blurred via
bilateral blur(based on temporal luminance variance)
- Reflections are traced with one shadow ray per-pixel and blurred via same filter that is used for shading
- Everything is combined based on material properties etc.
- Immediate 3D objects are drawn on top(with depth from G-Buffer)
- Immediate 2D objects are drawn on top
Current requirements to build development source code
1) VCPkg
2) Cmake
3) Visual Studio/CLion
4) C++ compiler with c++20
Build instructions
- Setup libraries via vcpkg(all dependencies are listed in response_file.txt)
- Prepare environment:
- GTA_3_FOLDER, GTA_VC_FOLDER and GTA_SA_FOLDER should be set to some places where you want resulting executables to
be.
- When building 32bit binaries use only BUILD_32BIT_LIBS
- When building 64bit binaries use BUILD_32BIT_LIBS and ARCH_64BIT
- Loading mod requires Ultimate ASI Loader installed.
- For GTA 3 it'll work only on steam, v1.1 and v1.0 at the moment.
- Build x86 and x64 libraries/executables in release or debug configuration using configured CMake.
- Run, test and report bugs and incompatibilities!
Tips
1) If you encounter bug please report it, and attach .log files and crash dumps and build/game version if possible to
bugreport
2) It's buggy and code is bad at the moment, sorry in advance :)