Cross Reference: /external/chromium_org/third_party/mesa/src/src/egl/main/

Notes about the EGL library:


The EGL code here basically consists of two things:

1. An EGL API dispatcher.  This directly routes all the eglFooBar() API
   calls into driver-specific functions.

2. Fallbacks for EGL API functions.  A driver _could_ implement all the
   EGL API calls from scratch.  But in many cases, the fallbacks provided
   in libEGL (such as eglChooseConfig()) will do the job.


Bootstrapping:

When the apps calls eglOpenDisplay() a device driver is selected and loaded
(look for dlsym() or LoadLibrary() in egldriver.c).

The driver's _eglMain() function is then called.  This driver function
allocates, initializes and returns a new _EGLDriver object (usually a
subclass of that type).

As part of initialization, the dispatch table in _EGLDriver->API must be
populated with all the EGL entrypoints.  Typically, _eglInitDriverFallbacks()
can be used to plug in default/fallback functions.  Some functions like
driver->API.Initialize and driver->API.Terminate _must_ be implemented
with driver-specific code (no default/fallback function is possible).


A bit later, the app will call eglInitialize().  This will get routed
to the driver->API.Initialize() function.  Any additional driver
initialization that wasn't done in _eglMain() should be done at this
point.  Typically, this will involve setting up visual configs, etc.


Special Functions:

Certain EGL functions _must_ be implemented by the driver.  This includes:

eglCreateContext
eglCreateWindowSurface
eglCreatePixmapSurface
eglCreatePBufferSurface
eglMakeCurrent
eglSwapBuffers

Most of the EGLConfig-related functions can be implemented with the
defaults/fallbacks.  Same thing for the eglGet/Query functions.


Teardown:

When eglTerminate() is called, the driver->API.Terminate() function is
called.  The driver should clean up after itself.  eglTerminate() will
then close/unload the driver (shared library).


Subclassing:

The internal libEGL data structures such as _EGLDisplay, _EGLContext,
_EGLSurface, etc should be considered base classes from which drivers
will derive subclasses.
Name	Date	Size
..	12-Mar-2015	4 KiB
.gitignore	12-Mar-2015	9
egl.def	12-Mar-2015	687
egl.pc.in	12-Mar-2015	275
eglapi.c	12-Mar-2015	42.8 KiB
eglapi.h	12-Mar-2015	10.3 KiB
eglarray.c	12-Mar-2015	4.7 KiB
eglarray.h	12-Mar-2015	2.3 KiB
eglcompiler.h	12-Mar-2015	3.8 KiB
eglconfig.c	12-Mar-2015	25.3 KiB
eglconfig.h	12-Mar-2015	7.2 KiB
eglcontext.c	12-Mar-2015	17.8 KiB
eglcontext.h	12-Mar-2015	4.1 KiB
eglcurrent.c	12-Mar-2015	8 KiB
eglcurrent.h	12-Mar-2015	2.8 KiB
egldefines.h	12-Mar-2015	1.6 KiB
egldisplay.c	12-Mar-2015	10.6 KiB
egldisplay.h	12-Mar-2015	6 KiB
egldriver.c	12-Mar-2015	15.2 KiB
egldriver.h	12-Mar-2015	3.6 KiB
eglfallbacks.c	12-Mar-2015	4.4 KiB
eglglobals.c	12-Mar-2015	2.5 KiB
eglglobals.h	12-Mar-2015	1.8 KiB
eglimage.c	12-Mar-2015	3.3 KiB
eglimage.h	12-Mar-2015	3.7 KiB
egllog.c	12-Mar-2015	5 KiB
egllog.h	12-Mar-2015	1.9 KiB
eglmisc.c	12-Mar-2015	4.9 KiB
eglmisc.h	12-Mar-2015	1.6 KiB
eglmode.c	12-Mar-2015	9.6 KiB
eglmode.h	12-Mar-2015	2.7 KiB
eglmutex.h	12-Mar-2015	2.3 KiB
eglscreen.c	12-Mar-2015	5.9 KiB
eglscreen.h	12-Mar-2015	3.5 KiB
eglstring.c	12-Mar-2015	1.7 KiB
eglstring.h	12-Mar-2015	1.8 KiB
eglsurface.c	12-Mar-2015	13.8 KiB
eglsurface.h	12-Mar-2015	4.6 KiB
eglsync.c	12-Mar-2015	3.3 KiB
eglsync.h	12-Mar-2015	3.3 KiB
egltypedefs.h	12-Mar-2015	2.2 KiB
Makefile.am	12-Mar-2015	3.7 KiB
README.txt	12-Mar-2015	2 KiB
SConscript	12-Mar-2015	1 KiB