This tries to deal with the crazy EGL situation. The summary is:
- using eglGetDisplay() with multiple windowing platforms doesn't really
work, but Mesa had an awful hack for it
- this hack can be disabled at build time, and some distros sometimes
accidentally or intentionally do so
- Mesa will probably eventually disable it by default
- we switched to eglGetPlatformDisplay(), but this requires EGL 1.5
- the very regrettable graphics company (also known as Nvidia) ships
drivers (for old hardware I think) that are EGL 1.4 only
- that means even though we "require" EGL 1.5 and link against it, the
runtime EGL may be 1.4
- trying to run mpv there crashes in the dynamic linker
- so we have to go through some more awful compatibility hacks
This commit tries to do it "properly", but using EGL 1.4 as base. The
plaform selection mechanism is a messy extension there, which got
elevated to core API in 1.5 (but OF COURSE in incompatible ways).
I'm not sure whether the EGL 1.5 code path (by parsing the EGL_VERSION)
is really needed, but if you ask me, it feels slightly saner not to rely
on an EGL 1.4 kludge forever. But maybe this is just an instance of
self-harm, since they will most likely never drop or not provide this
API.
Also, unlike before, we actually check the extension string for the
individual platform extensions, because who knows, some EGL
implementations might curse us if we pass unknown platform parameters.
(But actually, the more I think about this, the more bullshit it is.)
X11 and Wayland were the only ones trying to call eglGetPlatformDisplay,
so they're the only ones which are adjusted in this commit.
Unfortunately, correct function of this commit is unconfirmed. It's
possible that it crashes with the old drivers mentioned above.
Why didn't they solve it like this:
struct native_display {
int platform_type;
void *native_display;
};
Could have kept eglGetDisplay() without all the obnoxious extension BS.
This is done in several steps:
1. refactor MPGLContext -> struct ra_ctx
2. move GL-specific stuff in vo_opengl into opengl/context.c
3. generalize context creation to support other APIs, and add --gpu-api
4. rename all of the --opengl- options that are no longer opengl-specific
5. move all of the stuff from opengl/* that isn't GL-specific into gpu/
(note: opengl/gl_utils.h became opengl/utils.h)
6. rename vo_opengl to vo_gpu
7. to handle window screenshots, the short-term approach was to just add
it to ra_swchain_fns. Long term (and for vulkan) this has to be moved to
ra itself (and vo_gpu altered to compensate), but this was a stop-gap
measure to prevent this commit from getting too big
8. move ra->fns->flush to ra_gl_ctx instead
9. some other minor changes that I've probably already forgotten
Note: This is one half of a major refactor, the other half of which is
provided by rossy's following commit. This commit enables support for
all linux platforms, while his version enables support for all non-linux
platforms.
Note 2: vo_opengl_cb.c also re-uses ra_gl_ctx so it benefits from the
--opengl- options like --opengl-early-flush, --opengl-finish etc. Should
be a strict superset of the old functionality.
Disclaimer: Since I have no way of compiling mpv on all platforms, some
of these ports were done blindly. Specifically, the blind ports included
context_mali_fbdev.c and context_rpi.c. Since they're both based on
egl_helpers, the port should have gone smoothly without any major
changes required. But if somebody complains about a compile error on
those platforms (assuming anybody actually uses them), you know where to
complain.
This is pretty trivial, but also quite annoying due to details like
mismatching eglGetProcAddress() function signature (most callers just
cast the function pointer), and ARM/Linux hacks. So move them all to one
place.
Preparation for the following commits. Since at least theoretically the
config selection depends on the context type (EGL_RENDERABLE_TYPE has
separate bits for ES 2, ES 3, and desktop GL), doing it any other way
would be too painful.
For X11 garbage we have to pass some annoying parameters to EGL context
creation. Add some sort of extensible API, so that adding a new
parameter doesn't break all callers. We still want to keep it as a
single function, because it's so nice isolating all the EGL nonsense API
boilerplate like this. (Did I mention yet that X11 and EGL are garbage?)
Also somewhat simplifies the vo_flags mess in the helper internals.
Add a function to egl_helpers.c for creating an EGL context and make
context_x11egl.c use it. This is meant to be generic, and should work
with other windowing APIs as well. The other EGL-using code in mpv can
be switched to it.
Until now, we've used system-specific API (GLX, EGL, etc.) to retrieve
the depth of the default framebuffer. (We equal this to display depth
and use the determined depth for dithering.)
We can actually retrieve this value through standard GL API, and it
works everywhere (except GLES 2 of course). This simplifies everything a
great deal.
egl_helpers.c is empty now. But I expect that some EGL boilerplate will
be moved to it, so don't remove it yet.
This is used for dithering, although I'm not aware of anyone who got
higher than 8 bit depth support to work on Linux.
Also put this into egl_helpers.c. Since EGL is pseudo-portable at best I
have no hope that the EGL context creation code in all the backends can
be fully shared. But some self-contained functionality can definitely be
shared.
wm4
Anton Kindestam
Niklas Haas