Module egl_context

EGL bootstrap for the GPU rendering path.

Initialises an EGLDisplay from the Wayland connection, or the default display on Android, picks an EGLConfig, and creates an EGLContext. Tries GLES 3 first and falls back to GLES 2 if the driver does not advertise it. On success returns an EglContext holding a glow::Context already pointed at the resolved GL functions; on failure returns Err( reason ) so the caller can fall back to the software path.

Per-surface, EglSurface wraps an EGLSurface on the platform’s window: on Wayland a wl_egl_window it owns, which EglSurface::resize must follow the surface’s size; on Android an ANativeWindow the backend holds, whose buffers follow ANativeWindow_setBuffersGeometry.

Both need a backend feature, wayland, android or windows; EglOffscreenContext, the runtime-free target of UiSurface, does not.

The bootstrap honours LTK_FORCE_SOFTWARE=1 by failing fast with a descriptive error. Backend selection is announced exactly once per process via eprintln!( "[ltk] render backend: {GLES3|GLES2|SOFTWARE (...)}" ) — the GPU branch logs from the constructors of EglContext and EglOffscreenContext, the SOFTWARE branch from log_software_fallback (called by each backend’s run).

Structs

• EglContext
  Process-wide EGL display + GLES context. Cheap to clone because the heavy state (Arc<EglInstance>, Arc<glow::Context>) is reference-counted; the raw EGL handles are POD.
• EglOffscreenContext
  Runtime-free EGL target for code that wants a GPU crate::render::Canvas without going through ltk::run.
• EglSurface
  Per-surface EGL window. On Wayland egl_window owns the wl_egl_window; it must outlive surface because EGL keeps a raw pointer into it. On Android the backend holds the ANativeWindow for as long. egl and display are kept so that Drop can call eglDestroySurface without requiring a &EglContext at the call site.

Functions

• log_software_fallback
  Log the SOFTWARE fallback once, with the reason. The GPU branch logs from the context’s constructor.