SDL_libretro

A libretro frontend library for SDL3.

Features

• Header-only C99 library
• Audio via SDL_AudioStream with dynamic rate control
• Input with gamepad, keyboard, mouse, lightgun, or pointer
• Save states and SRAM
• Memory access and memory-map descriptors (cheats, debuggers, RAM watching)
• Core options
• Fast-forward and slow-motion
• Rewind with delta compression
• Rumble
• On-screen display messages

Usage

Define SDL_LIBRETRO_IMPLEMENTATION in exactly one .c file before including the header:

#define SDL_LIBRETRO_IMPLEMENTATION
#include "SDL_libretro.h"

All other files include SDL_libretro.h normally without the define.

Quickstart

SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_GAMEPAD);
SDL_Window* window = SDL_CreateWindow("SDL_libretro", 800, 600, SDL_WINDOW_RESIZABLE);
SDL_Renderer* renderer = SDL_CreateRenderer(window, NULL);
 
SDL_Libretro* lr = SDL_Libretro_Create();
SDL_Libretro_LoadCore(lr, "core.so");
SDL_Libretro_LoadGame(lr, "game.rom");
 
while (!SDL_Libretro_ShouldQuit(lr)) {
    SDL_Event event;
    while (SDL_PollEvent(&event)) {
        SDL_Libretro_HandleEvent(lr, &event);
    }
 
    SDL_Libretro_Update(lr);
 
    SDL_RenderClear(renderer);
    SDL_Libretro_Render(renderer, lr, NULL);
    SDL_RenderPresent(renderer);
}
 
SDL_Libretro_Destroy(lr);

• API Documentation
• SDL_libretro_basic Example
• Demo

Build

git clone --recurse-submodules https://github.com/RobLoach/SDL_libretro.git
cd SDL_libretro
mkdir build && cd build
cmake ..
cmake --build .

SDL3 is fetched automatically via CMake FetchContent if not already installed on the system.

Emscripten

With the Emscripten SDK activated, configure through emcmake:

emcmake cmake -B build-web
cmake --build build-web

Configuration

Use macros before SDL_LIBRETRO_IMPLEMENTATION to change how SDL_Libretro behaves.

• SDL_LIBRETRO_ENABLE_REWIND_DELTA: Enable the XOR delta between rewind frames to reduce memory at the expense of performance

Dependencies

• SDL3 (fetched automatically if not installed)
• libretro.h (git submodule)
• SDL_ini.h (included)

License

[zlib/libpng](LICENSE)