These parameters are incorrectly regarded as mutable in G-IR making them
"incompatible" with languages that are explicit about mutability like
Rust. In order to clean up the code and expected API there, update the
signatures here, right at the source (instead of overriding them in
Gir.toml and hoping for the best).
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/1005>
We need different export decorators for the different libs.
For now no actual change though, just rename before the release,
and add prelude headers to define the new decorator to GST_EXPORT.
Except for gst/gl/gstglfuncs.h
It is up to the client app to include these headers.
It is coherent with the fact that gstreamer-gl.pc does not
require any egl.pc/gles.pc. I.e. it is the responsability
of the app to search these headers within its build setup.
For example gstreamer-vaapi includes explicitly EGL/egl.h
and search for it in its configure.ac.
For example with this patch, if an app includes the headers
gst/gl/egl/gstglcontext_egl.h
gst/gl/egl/gstgldisplay_egl.h
gst/gl/egl/gstglmemoryegl.h
it will *no longer* automatically include EGL/egl.h and GLES2/gl2.h.
Which is good because the app might want to use the gstgl api only
without the need to bother about gl headers.
Also added a test: cd tests/check && make libs/gstglheaders.check
https://bugzilla.gnome.org/show_bug.cgi?id=784779
e.g when wrapping a data pointer we don't want to map/unmap off the end of
pointer with the alignment bytes.
Instead track that information separately as maxsize is used for mapping by
GstMemory and thus represents a size without any alignment padding bytes.
This is made possible by a subclassable GstGLAllocationParams that holds
the allocation parameters
Every allocation would now go through gst_gl_base_memory_alloc with the
allocation parameters now being specified in a single struct to allow
extension by different allocators.
It handles the following
- GstAllocationParams -> gst_memory_init transformation
- Makes sure that map/unmap/create/destroy happen on the GL thread with
a GL context current.
- Holds a possible sysmem accessible data pointer with alignment.
- Holds the need upload/download transfer state
