https://github.com/eimamei/snake-qr

A simple and pure win32 Snake game, without any compressor trickery, just under 2,953 bytes!
https://github.com/eimamei/snake-qr

bloat-free c-programming lightweight qrcode snake win32

Last synced: 10 months ago
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A simple and pure win32 Snake game, without any compressor trickery, just under 2,953 bytes!

• Host: GitHub
• URL: https://github.com/eimamei/snake-qr
• Owner: EimaMei
• License: mit
• Created: 2023-08-18T11:01:13.000Z (almost 3 years ago)
• Default Branch: main
• Last Pushed: 2024-05-20T17:32:11.000Z (about 2 years ago)
• Last Synced: 2025-04-10T19:23:21.037Z (about 1 year ago)
• Topics: bloat-free, c-programming, lightweight, qrcode, snake, win32
• Language: C
• Homepage:
• Size: 28.3 KB
• Stars: 12
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# Snake QR



    

    
A simple and pure win32 Snake game, without any compressor trickery, just under 2,953 bytes!


    




# Context/Credit

The original source code was taken from MattKC's ["Can you fit a whole game into a QR code?" video](https://www.youtube.com/watch?v=ExwqNreocpg&ab_channel=MattKC) where he attempted to port the classic game of "Snake" into a single QR code using the Win32 API in C. Despite the efforts he failed and decided to use a compressor to complete the challange during the final stretch, which felt very lame and lazy to me. So much so that I took a glance at the source code to see if there were any optimizations to make.

My suspicions were proven correct as I was not only able to fit the program into the QR code threshold without changing its fundamental logic, but I also implememted some fixes and improvements compared to the original.

# Most notable changes

- No crinker/compressor is used to reduce the executable size. Only Win32 C code and some MSVC compiler flag shenanigans.

- A few visual and gameplay fixes have been added to the game to make it much closer to the [HTML version](https://www.mattkc.com/etc/snakeqr/snake-minified.html) that was shown in the video.

- You can pause the game now by pressing the enter key instead of the 'pause' or 'P' key.

- You can retry the game by pressing the 'R' key.

# Code/smaller changes

To see all of the differences it's best to compare [this repository's `snake.c`](https://github.com/EimaMei/snake-qr/blob/main/snake.c) and [the original](https://www.mattkc.com/etc/snakeqr/snake.c) side by side. Here is a compiled list of the changes:

## Space saving changes

- The input system has been reworked to utilize only 2 variables instead of using an array of valid inputs. This reduces quite a considerable amount of space inside the executable, as the game now does a whole less for the same result. 

- The food starts at a constant position instead of calling the `rand` function at startup.

- All integers are `size_t` (register-sized instructions are usually preffered in most cases).

- A custom `rand` is implemented instead of relying on the C standard version.

- Code to change the snake's color depending on the game state (playing/won/lost) has been reworked to be completely branchless.

- `WM_TIMER`'s `while` loop has been converted to a single `if` statement.

- Removed the `bool moved` variable in `WM_TIMER` and used `goto` instead.

- Removed the `else` statement at `if (snake_len == MAX_TILE_COUNT)`.

- Removed `GetModuleHandleA` and `AdjustWindowRect`.

- The app now uses stack memory instead of the heap to hold `snake_pos` (this reduces the amount of OS calls needed to be called).

- Removed `if (msg.message == WM_QUIT)` in the main loop.

- Removed `TranslateMessage` in the main loop.

## Bug fixes

- The original `snake.c` leaked memory by continuously not calling `DeleteObject` when using `CreateSolidBrush` despite [official documentation advising to cleanup after drawing](https://learn.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-createsolidbrush). The only caveat with this is that this unfortunately comes with the cost of additional binary space.

## Visual changes

- The apple is now green.

## Misc changes

- You can now retry the game at anytime by pressing 'R'.

- The game's performance has been improved (less branching, `PosEqual` does one check instead of 2, etc).

- The pause button has been changed from `VK_PAUSE` and `P` to `VK_ENTER`.

- Regular `WNDCLASSA` and `CreateWindowA` are used instead of the expanded versions.

- The game doesn't overallocate `dir_queue` like it did in the original.

# Building

NOTE: `cl.exe` is assumed to be x86, not x64. Compiling it in 64-bit will considerably increase the size of the binary.

## Windows

Just copy the terminal commands from `Makefile` and paste them into the terminal.

## Linux/*nix OSses

This requires downloading `msvc` from [msvc-wine](https://github.com/mstorsjo/msvc-wine). After that, just run `make` and you'll get correct binaries.

# Making the QR code

Once you compiled `snake.exe`, on Unix you can run `make qrcode` to generate `code.png`.