mdgui

Immediate-mode GUI library (C/C++) with an SDL3 Zig demo application.

API at a Glance

MDGUI_Input in = { .mouse_x = mx, .mouse_y = my, .mouse_down = down, .mouse_pressed = pressed, .mouse_wheel = wheel };
mdgui_begin_frame(ctx, &in);

if (mdgui_begin_window(ctx, "Debug Panel", 20, 20, 220, 140)) {
  static float volume = 0.6f;
  mdgui_label(ctx, "Audio", 8, 6);
  mdgui_slider(ctx, "Volume", &volume, 0.0f, 1.0f, 8, 6, -16);
  if (mdgui_button(ctx, "Apply", 8, 10, 60, 12)) {
    // handle click
  }
  mdgui_end_window(ctx);
}

mdgui_end_frame(ctx);

Repository Layout

• include/: Public headers (mdgui_c.h, primitives/font headers)
• src/: C/C++ implementation (mdgui_c.cpp, mdgui_glue.cpp)
• demo/: Zig demo app entrypoint (main.zig)
• scripts/release.sh: Optional helper scripts for POSIX release packaging
• scripts/release.ps1: Optional PowerShell helper for Windows release packaging

Build

Prerequisites:

• Zig 0.15.2 or newer
• C/C++ toolchain supported by your Zig target

Commands:

zig build
zig build run

Release Packaging (Cross-Platform)

POSIX (Linux/macOS):

./scripts/release.sh 0.1.0

Windows PowerShell:

./scripts/release.ps1 release 0.1.0

Artifacts:

• Linux/macOS: mdgui-<version>-<os>-<arch>.tar.gz
• Windows: mdgui-<version>-win64.zip

Notes

• Window identity is keyed by window title (mdgui_begin_window title string).
• For best behavior, keep titles stable across frames.

Render Backend Compatibility

mdgui now uses a pluggable render backend API instead of hard-wiring widget draw calls to SDL renderer APIs.

• Backend-agnostic core primitives/font code: src/mdgui_glue.cpp
• SDL compatibility backend implementation: src/mdgui_backend_sdl.cpp
• OpenGL compatibility backend adapter: src/mdgui_backend_opengl.cpp
• Vulkan draw-data backend (command stream): src/mdgui_backend_vulkan.cpp
• UI/window logic: src/mdgui_c.cpp
• Backend helper declarations: include/mdgui_backends.h

MDGUI_Context *ctx = mdgui_create(sdl_renderer);

For non-SDL renderers, provide a MDGUI_RenderBackend and create with:

#include "mdgui_backends.h"

MDGUI_BackendCallbacks callbacks = { ... };
MDGUI_RenderBackend backend = { ... };

// OpenGL adapter (for direct callback-style drawing):
mdgui_make_opengl_backend(&backend, &callbacks);

MDGUI_Context *ctx = mdgui_create_with_backend(&backend);

Credits

Heavily inspired by the old Nes Emulator "NESticle" by: Icer Addis