enGUI — Equinox Desktop Environment

A lightweight, freestanding desktop environment for EquinoxOS, written in C with a Lua scripting layer on top. enGUI runs as a Ring 3 user-space process: it talks to the kernel through syscalls, draws into its own backbuffer, and exposes a small immediate-mode GUI API to Lua so that windows, widgets and animations can be authored as plain .lua files.

Easily extensible system GUI for EquinoxOS — write your apps in Lua, render with the built-in EID drawing API.

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Features

• Double-buffered framebuffer rendering at the host display resolution (defaults to 1024×768, autodetected from the kernel via syscall 32).
• Lua 5.4 scripting layer (vendored under lua/) for all UI logic — no recompilation needed to change the desktop.
• Immediate-mode widgets: buttons, checkboxes, sliders, text input, with hit-testing driven by mouse state.
• Animation system built on eid_anim_t with easing curves (animCreate / animTo / animStep / animEval).
• Software cursor composited on top of the backbuffer every frame.
• File I/O bindings so Lua apps can read, save and enumerate files through EquinoxOS' VFS.
• Smooth ~50 FPS main loop using sys_yield() and the PIT-driven preemptive scheduler — no fixed sys_sleep throttle.

Repository layout

.
├── main.c         # Entry point: framebuffer setup, main loop, cursor blit
├── api_gui.c/.h   # C → Lua bindings (drawing, widgets, animations, IO)
├── lua/           # Vendored Lua 5.4 interpreter sources
├── scripts/
│   └── init.lua   # Default desktop: window manager, terminal, notepad, …
├── Makefile       # Builds sysgui.elf with the EquinoxOS x86_64-elf toolchain
└── LICENSE        # MIT

Building

enGUI is built as a freestanding ELF for the EquinoxOS user-space ABI. You will need:

• x86_64-elf-gcc and x86_64-elf-ld cross-compiler toolchain
• A checkout of the EquinoxOS SDK in a sibling ../../sdk directory (the Makefile picks up $(SDK_DIR)/lib/*.o and $(SDK_DIR)/include)

Then:

make            # produces sysgui.elf
make clean      # removes object files and the ELF

On Windows the Makefile automatically swaps rm -f for del.

The resulting sysgui.elf is loaded by EquinoxOS at virtual address 0x1000000 with entry point _start. At startup it expects the default desktop script at res/sysgui/init.lua on the target filesystem — copy scripts/init.lua there (or to wherever your boot image expects it).

How it works

┌───────────────────────┐    syscall 32     ┌────────────────────┐
│  main.c (Ring 3)      │ ────────────────► │  EquinoxOS kernel  │
│  • maps framebuffer   │ ◄──── phys fb ─── │  • PIT @ 50 Hz     │
│  • allocates backbuf  │                   │  • mouse / keyboard│
│  • runs Lua VM        │ ──── sys_yield ─► │  • VFS             │
└─────────┬─────────────┘                   └────────────────────┘
          │ register_gui_api(L)
          ▼
┌───────────────────────┐
│  scripts/init.lua     │  draws windows, handles input, animates
└───────────────────────┘

Each frame the C loop:

1. Polls mouse (int 0x80, syscall 7) and keyboard (SYS_GET_SCANCODE).
2. Decides whether a redraw is needed (input changed, animation active, or forced first frames).
3. Computes dt in ms from SYS_GET_TIME (1 tick = 2 ms at the kernel's 50 Hz PIT).
4. Invokes on_tick(dt) in Lua, which redraws everything into the backbuffer.
5. Composites the 8×8 software cursor on top and memcpys the backbuffer to VRAM.
6. Yields to the scheduler.

Lua API

api_gui.c registers the following globals into every Lua state via register_gui_api(L):

Function	Purpose
drawText(str, x, y, color)	Draw a string at (x, y) in 0xRRGGBB.
drawRect(x, y, w, h, color)	Filled rectangle.
drawGradient(x, y, w, h, c1, c2, vertical)	Two-stop linear gradient.
drawLine(x1, y1, x2, y2, color)	Single-pixel line.
button(...) / checkbox(...) / slider(...)	Immediate-mode widgets returning input state.
animCreate(duration, ease)	Allocate an animation slot, returns id.
animTo(id, target) / animStep(id, dt) / animEval(id)	Drive and sample animations.
getMouse() / getLastKey() / scancodeToAscii(sc, shift)	Input helpers.
getUptime() / getMemInfo()	System info.
readFile(path) / saveFile(path, data) / getFiles(dir)	VFS access.
exec(path)	Launch another program.

A minimal example (see scripts/init.lua for the full desktop):

function on_tick(dt)
    drawGradient(0, 0, 1024, 768, 0x0F1020, 0x1A1C2E, true)
    drawText("Hello, enGUI!", 32, 32, 0xFFFFFF)

    if button("Click me", 32, 64, 120, 28) then
        print("clicked!")
    end
end

Status

enGUI already boots a full desktop with a window manager, a terminal and a notepad app — see scripts/init.lua. Animations, mouse focus and file I/O all work end-to-end on real EquinoxOS builds. Expect rough edges: it is research/hobby OS code.

Contributing

Pull requests are welcome. Please keep:

• C code freestanding (no libc beyond what the SDK provides).
• Lua code compatible with the vendored Lua 5.4 build.
• Comments either in English or matching the surrounding style (existing code mixes English and Russian).

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Русская версия

enGUI — легковесная рабочая среда для EquinoxOS. Ядро написано на C, вся логика рабочего стола, окна и виджеты — на Lua 5.4. Процесс работает в пользовательском кольце (Ring 3), общается с ядром через syscalls, рисует в собственный бэкбуфер и поверх кладёт программный курсор.

Возможности

• Двойная буферизация на разрешении хоста (по умолчанию 1024×768).
• Встроенный интерпретатор Lua 5.4 — UI пишется без перекомпиляции.
• Immediate-mode виджеты: button, checkbox, slider, текстовый ввод.
• Система анимаций с easing-кривыми (animCreate / animTo / animStep / animEval).
• Биндинги к VFS EquinoxOS: readFile, saveFile, getFiles, exec.
• Плавный цикл рендера ~50 FPS на базе sys_yield() (вместо sys_sleep, который из-за PIT 50 Hz фактически давал ≥40 мс задержки).

Сборка

Нужен кросс-тулчейн x86_64-elf-gcc / x86_64-elf-ld и SDK EquinoxOS в ../../sdk рядом с репозиторием. Дальше:

make            # собирает sysgui.elf
make clean

sysgui.elf грузится по адресу 0x1000000 с точкой входа _start. При старте он ищет res/sysgui/init.lua в файловой системе EquinoxOS — положите туда scripts/init.lua.

Структура

Файл / каталог	Назначение
main.c	точка входа, главный цикл, отрисовка курсора
api_gui.c / api_gui.h	биндинги C → Lua: рисование, виджеты, анимации, IO
lua/	исходники Lua 5.4 (vendored)
scripts/init.lua	дефолтный рабочий стол: оконный менеджер, терминал, блокнот
Makefile	сборка под x86_64-elf
LICENSE	MIT

Lua API

Полный список функций — в таблице выше. Минимальный пример:

function on_tick(dt)
    drawGradient(0, 0, 1024, 768, 0x0F1020, 0x1A1C2E, true)
    drawText("Привет, enGUI!", 32, 32, 0xFFFFFF)

    if button("Кнопка", 32, 64, 120, 28) then
        print("нажали!")
    end
end