Add support to look for and use the EGL context in Windows if it was activated
instead of desktop OpenGL.
GstGL may have been built with or without EGL/libANGLE support, so if it were,
check in GstGL whether we have gst_gl_display_new_with_type() to create a
GstGLDisplay that is of the GST_GL_WINDOW_WIN32 type when we are using
Desktop OpenGL (WGL), otherwise we show messages indicating that envvars
need to be set to initialize GstGL properly.
Due to a bug in GstGL, the GstGLContext can only be set up successfully
if one of the following is true:
* An OpenGL 3.x or later emulator, such as Mesa is used (for WGL)
* The latest GstGL master is being used, at the time of writing (for
WGL)
* GTK, libepoxy and GstGL are all built only with WGL support (for WGL)
* EGL is being used in GTK at runtime
Special thanks to Matthew Waters for the help during the process.
GModule requires the .so file extension on macOS for historic reasons.
However Meson defaults to .dylib for modules, so we need to override
it to get the correct extension.
Fixes#3645.
This gracefully disable ffmpeg, gstreamer, cups and cloudprint optional
dependencies when they are not available, while still giving full
control to distributors using -Dauto_features=enabled.
Visual Studio does not allow decorating functions with '__declspec (dllexport)'
if a prototype exists and is not decorated with '__declspec (dllexport)' as
well, so we cannot just decorate g_io_module_[load|unload|query] in the various
module sources with G_MODULE_EXPORT because the prototypes of these functions
have been marked with _GLIB_EXTERN, which equates to 'extern' unless overridden
Fix this by overriding _GLIB_EXTERN with the appropriate visibility flag, as we
have used to define _GDK_EXTERN. Unfortunately, we can't just use _GDK_EXTERN
G_MODULE_EXPORT as they may have not been defined yet for our use
Do this across the board for all modules, even if they are not buildable on
Visual Studio nor Windows, for consistency's sake.
We need to override _GLIB_EXTERN to export the required symbols for the
GIO module on Visual Studio, so that the media modules can be
successfully loaded.
This way, we can support external libraries providing implementations of
GtkMediaFile.
We also add a media backend called 'nomedia' that can be enabled to not
compile any support for GtkMediaFile. This is useful when people want to
statically compile GTK into an application that does not use media.
For now, this option is the default.
We also support a new environment variable GTK_MEDIA that allows
selecting the implementation to use.
GTK_MEDIA=help can be used to get info about the available
implementations.