EGL 1.5 Implementation

A portable, spec-compliant implementation of EGL 1.5 built around a platform-agnostic core and pluggable OS/rendering backends. The library provides the standard EGL surface creation, context management, and synchronization API across operating systems, so that applications can share a single EGL-based rendering path regardless of the underlying platform.

The Khronos headers bundled with the library are the official, unmodified ones from the EGL Registry (commit e80a2e0050, 2026-03-19).

Platform and Backend Support

Operating System	Supported APIs	Platform API	Backend API	Status Quo
Windows	OpenGL	WGL, DXGI	Vulkan	Implemented
macOS / iOS	-	CGL, EAGL, CAMetalLayer	-	Prepared
Android	-	ANativeWindow	-	Prepared
Linux — X11	-	GLX	-	Prepared
Linux — Wayland	-	wl_egl_window	-	Prepared
Linux — DRM/KMS	-	GBM, libdrm	-	Prepared
Linux — ChromeOS	-	Ozone	-	Prepared
QNX	-	Screen API	-	Prepared
HarmonyOS (OHOS)	-	OHNativeWindow	-	Prepared
Haiku	-	BGLView	-	Prepared
Fuchsia	-	Scenic / Flatland	-	Prepared
WebAssembly	-	Emscripten	-	Prepared
Symbian (legacy)	-	Native	-	Prepared

EGL 1.5 API Coverage

The full EGL 1.5 API surface is implemented in the platform-agnostic core:

• Display management: eglGetDisplay, eglInitialize, eglTerminate, eglGetPlatformDisplay
• Config selection: eglGetConfigs, eglChooseConfig, eglGetConfigAttrib
• Context management: eglCreateContext, eglDestroyContext, eglMakeCurrent, eglGetCurrentContext, eglGetCurrentDisplay, eglGetCurrentSurface, eglQueryContext
• Surface management: eglCreateWindowSurface, eglCreatePbufferSurface, eglCreatePixmapSurface, eglCreatePlatformWindowSurface, eglCreatePlatformPixmapSurface, eglDestroySurface, eglQuerySurface, eglSurfaceAttrib
• Rendering: eglSwapBuffers, eglSwapInterval, eglCopyBuffers, eglBindTexImage, eglReleaseTexImage, eglWaitClient, eglWaitNative
• Sync objects (EGL 1.5 / GL_ARB_sync): eglCreateSync, eglDestroySync, eglClientWaitSync, eglWaitSync, eglGetSyncAttrib, eglSignalSync
• Image objects: eglCreateImage, eglDestroyImage
• Threading: eglBindAPI, eglQueryAPI, eglReleaseThread (per-thread state via thread_local)
• Utilities: eglGetError, eglGetProcAddress, eglQueryString

HDR Support

The following colorspace extensions are probed at eglInitialize time and advertised only if the driver and display support them:

Extension	Colorspace	Format
EGL_EXT_gl_colorspace_scrgb_linear	scRGB linear	R16G16B16A16_SFLOAT
EGL_EXT_gl_colorspace_scrgb	scRGB gamma	R16G16B16A16_SFLOAT
EGL_EXT_gl_colorspace_bt2020_pq	BT.2020 PQ / HDR10	A2B10G10R10_UNORM
EGL_EXT_gl_colorspace_bt2020_linear	BT.2020 linear	R16G16B16A16_SFLOAT
EGL_EXT_gl_colorspace_bt2020_hlg	BT.2020 HLG	A2B10G10R10_UNORM
EGL_EXT_gl_colorspace_display_p3	Display P3 (sRGB EOTF)	R8G8B8A8_UNORM
EGL_EXT_gl_colorspace_display_p3_linear	Display P3 linear	R16G16B16A16_SFLOAT
EGL_EXT_gl_colorspace_p3_passthrough	Display P3 passthrough	R8G8B8A8_UNORM

Building

Windows (implemented)

Requirements: CMake 3.10+, MSVC (Visual Studio 2019+), Vulkan SDK.

mkdir build
cd build
cmake ..
cmake --build .

Release build:

cmake -DCMAKE_BUILD_TYPE=Release ..
cmake --build . --config Release

Outputs: lib/libEGL.lib and the example executables under bin/.

If CMake cannot find the Vulkan SDK, ensure VULKAN_SDK is set in your environment.

Other platforms (prepared)

Cross-compile with the target toolchain. CMake selects the correct platform branch automatically based on CMAKE_SYSTEM_NAME. For Linux sub-platforms pass the appropriate define:

# Wayland
cmake .. -DWL_EGL_PLATFORM=1

# GBM / DRM-KMS
cmake .. -DGBM_PLATFORM=1

# Ozone
cmake .. -DOZONE_PLATFORM=1

Non-Windows builds will compile until the link stage and then fail on the 17 unimplemented __ backend functions — this is intentional and indicates where the new backend code goes.

Examples

Executable	Colorspace	HDR
srgb	sRGB	No
linear	Linear	No
scrgb_linear	scRGB linear	Yes
scrgb	scRGB gamma	Yes
bt2020_pq	BT.2020 PQ / HDR10	Yes
bt2020_linear	BT.2020 linear	Yes
bt2020_hlg	BT.2020 HLG	Yes
display_p3	Display P3 (sRGB EOTF)	No
display_p3_linear	Display P3 linear	No
display_p3_passthrough	Display P3 passthrough	No

Each example checks at runtime whether its colorspace is supported and exits with a message if not.

Architecture

egl.c                     Public C API (thin shims, no logic)
  └── egl_globals.cpp      Global + per-thread storage, init/terminate lifecycle
  └── egl_config.cpp       Config selection and queries
  └── egl_display.cpp      Display management and extension string
  └── egl_context.cpp      Context create/destroy/makecurrent
  └── egl_surface.cpp      Surface create/destroy/query
  └── egl_sync.cpp         Sync objects (EGL 1.5)
  └── egl_image.cpp        Image objects (EGL 1.5)
  └── egl_api.cpp          Swap, bind, wait, getProcAddress

  Internal headers:
  └── egl_internal.h       Backend interface declarations (implemented by platform backends)
  └── egl_common.h         Shared internal types and helpers
  └── egl_windows_vk.h     Windows Vulkan HDR — internal declarations for egl_windows_vk.cpp
  └── wglext.h             WGL extension prototypes (Windows)

  Platform backends (implement the functions declared in egl_internal.h):
  └── egl_windows.cpp      Windows — WGL
  └── egl_windows_vk.cpp   Windows — Vulkan HDR presentation
  └── egl_<platform>.cpp   Future backends

Yours Norbert Nopper

Changelog

19.04.2026 - Major refactoring using AI v1.0.0.

29.01.2015 - Updated to GLEW 1.12.0. v0.3.3.

25.01.2015 - Fixed initialization bug on Windows. v0.3.3.

20.01.2015 - Added GLX version check. Fixed window creation bug on X11. v0.3.2.

05.12.2014 - Removed duplicate code. v0.3.1.

04.12.2014 - Working X11 version. v0.3.0.

28.11.2014 - Continued X11 implementation. v0.2.3.

22.11.2014 - X11 compiling but not complete. v0.2.2.

18.11.2014 - Added X11 build configuration. v0.2.1.

17.11.2014 - First public release. v0.2.