ZigRain

Simple rain animation in Zig

ZigRain

A simple rain animation built with Zig 0.16.0,to demonstrate practical use of Zig's new I/O APIs and C interoperability.

ZigRain animates falling raindrops across your screen using SDL2 for graphics. It's an educational project created to explore Zig 0.16.0's evolving language features and how seamlessly Zig integrates with C libraries.

Key Learning Goals

Zig's New I/O Context System

I wanted to use Zig 0.16.0's refactored I/O model. Instead of relying on global state, creating an IoSource from the process initialization context and using it to seed a cryptographically secure random number generator. Demonstrates the modern, composable approach to I/O in recent Zig versions.

C Interoperability

I also wanted to explore @cImport to bring in SDL2 and directly call C functions from Zig code. This is practical C interop, no wrapper libraries, just clean integration with a mature graphics library. Notice how Zig's @cInclude directive handles the C types and how error handling works across language boundaries.

Build Configuration: (Bypassing the zld .sframe Bug)

The build system forces the LLVM toolchain and LLD linker. (use_llvm = true, use_lld = true in build.zig). This works around a known issue with macOS's default zld linker and .sframe sections. If you're building on other platforms, these settings are safe but unnecessary. Adjust for your environment.

Building & Running

zig build run

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The build system handles SDL2 linking automatically. Make sure SDL2 development headers are installed on your system.

On macOS with Homebrew:

brew install SDL2

On Linux (Ubuntu/Debian):

sudo apt-get install libsdl2-dev

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How It Works

The program:

• Initializes SDL2 and creates a window.
• Seeds a random number generator from the process I/O context.
• Spawns 150 raindrops at random positions.
• Animates them falling downward each frame, respawning at the top when they exit the screen.
• Renders at 60 FPS.

Exit by closing the window or pressing ESC. Project Structure.

 main.zig : Core animation loop and rain physics
build.zig : Build configuration with C library linking

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This project was a way for me to bridge the gap between learning a new language feature, and using it in a real context. Modern Zig emphasizes explicit control over I/O and resource management. this rain animation seemed like a nice stepping stone for me to see that philosophy in action.