Aeron

Aeron is a portable engine foundation for games that need to combine classic software-rendered content with a modern GPU renderer. It provides the common runtime, rendering, media, input, and asset-processing services used by OpenXWA and OpenTIE.

Aeron uses SDL3 to provide a native application runtime across current desktop operating systems. It manages the window, timing, input, audio, logging, YAML configuration, platform integration, and a virtual file system for application resources and game data. Keyboard, mouse, text input, gamepads, and controller rumble are exposed through a consistent per-frame input snapshot.

Aeron can combine CPU-generated frames, GPU textures, and direct GPU drawing as ordered layers in one final image. This allows a game to preserve its original framebuffer, interface, and cockpit composition while adding GPU-rendered elements where appropriate. It handles legacy indexed and true-color frames, palette and color-key behavior, resolution-independent scaling, resizable windows, and SDR or HDR output.

Aeron provides a portable C graphics layer over SDL_GPU. Shared HLSL shaders are compiled to Metal Shading Language, SPIR-V, and DXIL for the supported graphics backends.

The shared scene renderer provides:

• glTF meshes, KTX2 textures, physically based materials, material variants, and articulated mesh parts;
• point lights, cascaded directional shadows, sky cubes, billboards, lens effects, and 2D sprite and text drawing;
• SSAO, bloom, motion blur, SDR/HDR tone mapping, and AMD FidelityFX FSR 3.1.4 native AA and temporal upscaling.

Games remain responsible for translating their authoritative state into Aeron's game-neutral scene and can extend its rendering passes where game-specific behavior is required.

The software audio mixer supports sound effects, positional audio, and streamed speech or music.

The optional FFmpeg-backed video player decodes audio and video asynchronously, reads through the virtual file system, and presents decoded frames through the same layer compositor as the rest of the application.

Aeron includes shared tools and libraries for preparing original and remastered assets:

• opt2gltf converts LucasArts OPT models to glTF while preserving engine metadata such as articulated parts, hardpoints, and material variants;
• aeron_gltf_cook converts artist-authored glTF assets into the runtime GLB representation and builds material channel atlases;
• imgbake handles image scaling, texture and font atlases, and compressed KTX2 texture generation.

Optional Dear ImGui tools can be registered by a game for live diagnostics. Aeron also names GPU resources and annotates render and compute work so frames are easier to inspect in tools such as RenderDoc and Xcode's Metal debugger.

Aeron is under active development alongside OpenXWA and OpenTIE. Its runtime, renderer, media systems, and asset tools are already used by both projects. It is developed as a shared source dependency rather than as a separately versioned SDK, and its interfaces continue to evolve.

Aeron targets the same desktop platforms and SDL_GPU backends as the game projects:

Shader sources are shared across all three platforms and compiled into the native format required by each backend.

Aeron is normally included in a game repository as a Git submodule and added with CMake's add_subdirectory().

Building requires CMake 3.20 or later, a C99/C++17 toolchain, SDL3 3.4, zstd, and SDL_shadercross. FFmpeg and pkg-config are also required when video support is enabled.