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https://github.com/gargakshit/nes
Yet another NES emulator in C++
https://github.com/gargakshit/nes
cpp emulation hacktoberfest nes opengl
Last synced: 1 day ago
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Yet another NES emulator in C++
- Host: GitHub
- URL: https://github.com/gargakshit/nes
- Owner: gargakshit
- License: bsd-3-clause
- Created: 2023-10-01T09:22:03.000Z (over 1 year ago)
- Default Branch: master
- Last Pushed: 2023-10-13T07:03:14.000Z (over 1 year ago)
- Last Synced: 2025-01-15T02:58:19.874Z (4 days ago)
- Topics: cpp, emulation, hacktoberfest, nes, opengl
- Language: C++
- Homepage:
- Size: 728 KB
- Stars: 3
- Watchers: 2
- Forks: 1
- Open Issues: 3
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# Yet another NES emulator.
## Why?
It's been quite long since I last wrote an emulator, and I wanted to get into
emulating a classic system.
## Why C++? Isn't it unsafe bla bla?
Well personally, I find C++ to be good while writing emulators. I should
probably try rust or zig, but it is what it is.
## Umm how does it work?
The emulator is divided into several different subsystems,
- **Graphics and GUI subsystem** – The name says it all. I use OpenGL (yes even
on Apple systems, it is "good enough" for my use-case) along with
[GLFW](https://github.com/glfw/glfw) and
[Dear ImGui](https://github.com/ocornut/imgui).
I have a custom [image class](./src/image.cpp) to send images to the GPU for
drawing. Other than the image class, and the application entrypoint, nothing
is coupled to OpenGL, and in theory I can replace it with Vulkan, or even use
it platform specific implementations for Metal and DirectX in the future.
- **CPU** – The classic MOS 6502 without the decimal mode.
- **Bus** - Technically the whole NES system, as everything comes together here.
What even is CPU in isolation?
- **PPU** – The picture processing unit of the NES.
- **APU** (WIP) – Audio processing unit. I haven't implemented this yet.
- **Carts and mappers** – The plasic with a PCB inside.
## How to build?
You'll need a couple things installed before you can get going,
- CMake
- Ninja (or `make`)
- Clang (Can probably use GCC but MSVC won't work for sure)
- vcpkg
- XCode on macOS / Visual Studio with the C++ desktop workload on Windows
You can then build it in release mode using
```sh
$ cmake -Bcmake-build-release -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -GNinja -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=[path to vcpkg]/scripts/buildsystems/vcpkg.cmake
$ ninja -Ccmake-build-release
```
### What about debug mode?
Well you can build it in debug mode as-well, but keep in mind that it enabled `trace`
level logging which logs ~50 lines per machine cycle, and the machine runs at 5.3MHz.
You run the risk of logging **gigabytes** of logs.
Also, it enables address sanitizer which decreases program speed by a factor of two.
It is recommended to build in release unless you know what you are doing.