libegl

#ABOUT

libegl is a cross platform EGL implementation for the following platforms:

• Apple iOS

See CHANGELOG file for further details.

#MOTIVATION:

I am writing cross-platform C/C++ libraries and I needed a cross platform C EGL implementation for my iPhone port.

# WHAT IS EGL ?

> EGL provides mechanisms for creating rendering surfaces onto which client APIs > like OpenGL ES and OpenVG can draw, creates graphics contexts for client APIs, > and synchronizes drawing by client APIs as well as native platform rendering APIs. > This enables seamless rendering using both OpenGL ES and OpenVG for high-performance, > accelerated, mixed-mode 2D and 3D rendering.

Khronos Group

Please refer to [official Khronos Group website](https://www.khronos.org/) for further details about [EGL](https://www.khronos.org/egl/). Especially [Khronos EGL Registry ](https://www.khronos.org/registry/egl/).

#DOCUMENTATION

The source code is partially documented although EAGL iOS driver aims to be fully documented in the near future.

Major design decisions are [documented](http://www.mesa3d.org/egl.html).

##How to get started on iOS ?

###How to compile the library ?

cd proj && make build-all-release

###Build flavors

cd proj && make usage

###Where are the compilation artifacts ?

Upon sucessful project compilation, directory "prefix" will contains:

• static library .a file for your project to link with.
• EGL header files declaring EGL functions

###What are the dependencies/linker settings required to link with ?

Static library .a file requires:

• to be linked with:

  • OpenGLES.framework
  • CoreGraphics.framework
  • UIKit.framework
  • QuartzCore.framework

• to have the following PREPROCESSOR macros defined:

  • HAVE_PTHREAD=1
  • _EGL_NATIVE_PLATFORM=_EGL_PLATFORM_IOS
  • _EGL_OS_APPLE_IOS=1
  • _EGL_BUILT_IN_DRIVER_IOSEAGL=1
  • DEBUG=1 (optional)

# ARC vs MRR support

The code is fully compatible with MRR. ARC support is on the way.

#SOURCE

Main source repository:

https://github.com/davidandreoletti/eglapi-core-lib.git

#DEVELOPMENT STATUS

This implementation is in ALPHA version. I only implements features required for my own needs but feel free to extend it. The tables below describes what is supported in this implementation.

##Nomenclature

• Supported: The feature is implemented and fully/partially tested
• unsupported: The feature is not implemented due to either technically infeasibility OR not yet planned
• planned: The feature will be implemented for a future release

## EGL Core API

### iOS SDK supported

|-----------------|-----------| | 4.3+ | Supported |

###EGL API version supported

|-----------------|-----------| | 1.4 | Supported |

###Datatypes

|--------------------------|----------------|------------------------|---------| | EGLNativeDisplayType | Supported | UIWindow* | | | EGLNativePixmapType | Unsupported | None | | | EGLNativeWindowType | Supported | CAEAGLayer | |

###Client APIs

|----------------------------------|------------------------|-----------------------------------------------| | EGL_OPENGL_ES_BIT | Supported | | | EGL_OPENGL_ES2_BIT | Supported | | | EGL_OPENGL_ES3_BIT_KHR | Supported | See "EGL_KHR_create_context" EGL extension | | EGL_OPENGL_BIT | Unsupported | | | EGL_OPENVG_BIT | Unsupported | |

###EGL Functions

|----------------------------------|------------------------|---------| | eglGetDisplay | Supported | | | eglInitialize | Supported | | | eglQueryString | Supported | | | eglGetConfigs | Supported | | | eglChooseConfig | Supported | | | eglBindAPI | Supported | | | eglCreateContext | Supported | | | eglDestroyContext | Supported | | | eglCreateWindowSurface | Supported | EGLNativeWindowType MUST remain valid for as long as the EGLSurface handle is valid | | eglCreatePbufferSurface | Unsupported | | | eglCreatePixmapSurface | Unsupported | | | eglDestroySurface | Supported | | | eglQuerySurface | Supported | | | eglQueryAPI | Supported | | | eglQueryContext | Supported | | | eglSurfaceAttrib | Planned | | | eglMakeCurrent | Partially supported | | | eglGetCurrentContext | Supported | | | eglGetCurrentSurface | Supported | | | eglGetCurrentDisplay | Supported | | | eglGetConfigAttrib | Supported | | | eglSwapBuffers | Supported | | | eglSwapInterval | Planned | | | eglWaitClient | Planned | | | eglWaitGL | Planned | | | eglWaitNative | Unsupported | | | eglBindTexImage | Unsupported | | | eglReleaseTexImage | Unsupported | | | eglCopyBuffers | Unsupported | | | eglCreatePbufferFromClientBuffer | Unsupported | | | eglSwapInterval | Supported | | | eglGetProcAddress | Planned | | | eglGetError | Supported | | | eglReleaseThread | Supported | | | eglTerminate | Planned | |

##EGL Extensions

### EGL_KHR_create_context

Only attribute EGL_OPENGL_ES3_BIT_KHR is supported. Anything else has not been tested and most likely not supported.

#TESTING

See "test" directory

#SAMPLES

See "samples" directory.

#CHANGELOG

See CHANGELOG file

#REQUIREMENTS

See CHANGELOG file

#DONATING

Gittip:

[](https://www.gittip.com/davidandreoletti)

Bitcoin:

1DaE8Dq4rm9XQKh2Po4pskiwZK526r4xUT

#CONTRIBUTORS:

If you would like to contribute, feel free to drop me an email or contribute patches/pull requests.

#AUTHOR

• David Andreoletti http://davidandreoletti.com

#THANKS TO

• [Mesa 3D Graphic Library](http://www.mesa3d.org) This port is greatly inpired from their implementation. Special thanks to you guys :)

  • Changeset used: 56ea2c4816dbcdbdabe7718423828fdb2ee1c95b

• [Alexei Sholik's iOS EGL prototype](https://github.com/alco/EGL_mac_ios) - This implementation did show me it was technically possible.