LIMEN

is the SDL3 platform and graphics integration for HashLink NMB.

SDL owns windows, displays, fullscreen state, input, cursors, clipboard, drag-and-drop, and native event delivery. OpenGL, Vulkan, Direct3D 11, and Direct3D 12 own GPU rendering only.

Important

This repository is the canonical implementation. HashLink embeds it through its LIMEN_SOURCE_DIR CMake option.

Haxe API

The public API follows the native subsystem layout:

import limen.platform.Platform;
import limen.platform.Window;
import limen.platform.event.Event;
import limen.platform.input.gamepad.Gamepad;

Platform.init();

final window = Window.create({
	title: "LIMEN",
	width: 1280,
	height: 720,
	resizable: true
});
final displays = limen.platform.display.Display.all();
final modes = limen.platform.display.Display.modes(displays[0].id);

final event = new Event();
while (Platform.pollEvent(event)) {
	// Handle the event.
}

window.destroy();
Platform.quit();

Platform types are grouped under limen.platform.event, limen.platform.cursor, limen.platform.input, limen.platform.display, and limen.platform.system.

Graphics backends own their context and device setup. For example, an OpenGL window uses Window.SDL_WINDOW_OPENGL and limen.graphics.opengl.Context.create(window). D3D12 concepts live under limen.graphics.d3d12.command, descriptor, pipeline, query, resource, and shader. Vulkan follows the equivalent package structure.

The native build produces exactly:

limen.hdll - Core of LIMEN
opengl.limen - GL driver (includes on all targets)
vulkan.limen - Vulkan driver (includes on all targets)
d3d11.limen - Direct3D 11 (includes on all Windows targets)
d3d12.limen - Direct3D 12 (includes on Win64 ONLY)
dlss.limen - DLSS (optional, includes on Win64 and with D3D12 ONLY)

Platform.init() prefers OpenGL as the minimum backend. Pass another GraphicsDriver to request it first. If that module is missing or cannot be loaded, LIMEN falls back to OpenGL and then to any other available driver. The selected backend is exposed as Platform.graphicsDriver. Initialization fails with No LIMEN graphics driver was found when no driver module exists. Applications that compile only a subset of renderers can pass that subset as the second argument so fallback never selects an unavailable implementation. DLSS.isAvailable() is true only when D3D12 is selected and dlss.limen loads successfully.

Windows build and install directories also contain the dynamically linked runtime DLLs beside the modules:

Contains and using only by Direct3D 12

dxcompiler.dll
dxil.dll

Standalone build

cmake -S . -B build \
  -DLIMEN_HASHLINK_ROOT=/path/to/hashlink-nmb \
  -DLIMEN_BUILD_OPENGL=ON \
  -DLIMEN_BUILD_VULKAN=ON \
  -DLIMEN_BUILD_D3D11=ON \
  -DLIMEN_BUILD_D3D12=ON
cmake --build build

SDL3 is built statically by CMake. Set LIMEN_SDL3_SOURCE_DIR to use a local SDL3 source tree instead of the pinned fetched release.

DLSS support is disabled by default and is not required to build or install LIMEN. On Windows x64, set LIMEN_BUILD_DLSS=ON and LIMEN_STREAMLINE_SDK_ROOT to build dlss.limen; the Streamline import library and runtime DLLs are required only for that opt-in module.

CMake locates the DXC runtime DLLs from the Vulkan SDK or HashLink's include/dx distribution. Their locations can be overridden with LIMEN_DXCOMPILER_RUNTIME_DLL and LIMEN_DXIL_RUNTIME_DLL.

Set LIMEN_BUILD_AFTERMATH=ON to add NVIDIA Nsight Aftermath GPU crash diagnostics to the D3D12 backend. Set LIMEN_AFTERMATH_SDK_ROOT to the SDK root, or define NSIGHT_AFTERMATH_SDK; CMake links the matching x64 or x86 import library and packages its runtime DLL beside d3d12.limen. The include directory, library, and runtime DLL can be overridden with LIMEN_AFTERMATH_INCLUDE_DIR, LIMEN_AFTERMATH_LIBRARY, and LIMEN_AFTERMATH_RUNTIME_DLL.

Enable LIMEN_BUILD_TESTS for the native event-translation tests.

HashLink integration

HashLink NMB pins LIMEN as the libs/limen submodule and builds it directly with CMake. To test changes without updating that pin, configure HashLink against this checkout:

cmake -S /path/to/hashlink-nmb -B /path/to/hashlink-nmb/build \
  -DLIMEN_SOURCE_DIR=/path/to/Limen

After a LIMEN revision passes CI, update HashLink's libs/limen submodule. The gitlink is the single source of truth for the pinned revision. HashLink's manual Pin LIMEN revision workflow updates it after the integration matrix succeeds.