Our caller may load (eg) epoxy_glAlphaFunc, which is a function pointer,
and then call through that value multiple times. Until the caller
re-examines the value of that function pointer, which is a copy
relocation in the executable, repeated calls mean repeated work
resolving the GL function.
We can't make the caller reinspect the variable, but the resolver
function can avoid doing redundant work.
Fixes: anholt/libepoxy#171
Signed-off-by: Adam Jackson <ajax@redhat.com>
Now that we're being conservative about probing libraries, these
entrypoints would not succeed unless the caller had already dlopened
stuff themselves, or had explicitly linked against the provider library.
Both of those are exactly not what we want.
Signed-off-by: Adam Jackson <ajax@redhat.com>
Epoxy can be compiled with GLX and X11 native resources on EGL. We can
disable the former, but the latter is always built in when enabling EGL
support.
Some platforms do not support X11 at all, so we need a way to disable
X11 when configuring Epoxy.
The EGL_EXT_device_query extension introduces the
eglQueryDeviceStringEXT() function, which can be used with an
EGLDeviceEXT enumeration to receive an OpenGL extension string
containing all of the device extensions supported by it. From the
EGL_EXT_device_query spec's amendments to section "3.2 Devices" after
"3.1 Errors":
const char *eglQueryDeviceStringEXT(EGLDeviceEXT device,
EGLint name);
returns a pointer to a static, zero-terminated string describing
some aspect of the specified EGLDeviceEXT. <name> must be
EGL_EXTENSIONS.
Since OpenGL extension parsing is rather simple, and we could always run
into additional cases similar to this one in the future, we expose the
shared epoxy_extension_in_string() function in libepoxy's public headers
so that users can save themselves the hassle of having to write their
own extension parser.
Signed-off-by: Lyude Paul <thatslyude@gmail.com>
It is perfectly possible to build Mesa3D with just OpenGL support, and
use with GLX in X.org, without having EGL/OpenGLES support.
However, libepoxy currently unconditionally requires EGL support in its
configure.ac, which causes a build failure when Mesa3D only provides
full OpenGL support:
checking for EGL... no
configure: error: Package requirements (egl) were not met:
Package egl was not found in the pkg-config search path.
Perhaps you should add the directory containing `egl.pc'
to the PKG_CONFIG_PATH environment variable
Package 'egl', required by 'world', not found
This commit fixes that by:
- Adjusting the configure.ac to add a --{enable,disable}-egl option
handled in the exact same way as --{enable,disable}-glx
- Adjusting the meson build logic in the same way.
- Adjusting src/dispatch_common.h to define PLATFORM_HAS_EGL correctly,
which allows to not include any EGL related header file if EGL
support is not enabled.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Currently, GLX support in libepoxy at build time is hard coded, but
various platforms have expressed their preference for having a
configure-time option for it.
For instance:
- various embedded distributors do not ship with X11, but wish to use
libraries that depend on libepoxy now that Wayland is available
- distributors for macOS still wish to retain the ability to ship
their software with X11 enabled
By default, we want epoxy to build with GLX enabled pretty much
everywhere it makes sense, since it's only a build-time option and it's
not a run-time dependency.
When checking whether GLX or EGL are available on the system, we don't
want to use the internal API that forces an exit() on missing libraries
and symbols — as that would defeat the point.
Instead, we should have safe functions to call internally that simply
return a NULL pointer, so we can bail out ourselves in a controlled
fashion.
To avoid a symbols file on Windows, Epoxy annotates all the publicly
visible symbols directly in the source, but uses the default symbol
visibility everywhere else. This means that only some symbols are
annotated as `EPOXY_IMPORTEXPORT`, and generally only on Windows.
Additionally, Epoxy has a private 'PUBLIC' pre-processor macro for
internal use, which duplicates the `EPOXY_IMPORTEXPORT` but contains
more logic to detect GCC, in case we're building with GCC on Windows.
This would be enough, except that EGL is also available on Windows,
which means we'd have to annotate the exported `epoxy_*` API inside
epoxy/egl.h as well. At that point, though, we should probably avoid
any confusion, and adopt a single symbol visibility policy across the
board.
This requires some surgery of the generated and common dispatch sources,
but cuts down the overall complexity:
- there is only one annotation, `EPOXY_PUBLIC`, used everywhere
- the annotation detection is done at Epoxy configuration time
- only annotated symbols are public, on every platform
- annotated symbols are immediately visible from the header
Define PACKED for Visual Studio builds, so that we can try to reduce
our library size for Visual Studio builds. Add a ENDPACKED macro
that is currently defined only for Visual Studio builds as packing is
done via __pragma(pack(push,n), that should be popped when done.
Signed-off-by: Emmanuele Bassi <ebassi@gnome.org>
Most of the changes that happened after commit 8bbc0d40 broke epoxy
pretty much irreparably because of the CMake build and the attempt at
making libepoxy a static library that can be copy-pasted into another
project without generating files.
Since all the commits are entangled, and are full of unrelated changes,
we cannot simply do a localized set of reverts; instead, we need to hit
the reset button.
From this point forward, we're going to improve libepoxy's build while
attempting to keep the existing build system working. This may mean
reinstating the CMake build system at a later date.
Since our provider enums are small, we can store them as bytes or
shorts if we just let the compiler know that it's OK. Saves 20kb in
the compiled library.
This has been tested with both OpenGL and OpenGL ES on Android.
We can't use dlsym on Android to get all the function pointers since Android's libGLES* libraries are just shim libraries that pass everything through
to the real vendor specific libraries.
Due to this we must grab function pointers entirely through eglGetProcAddress instead of dlsym.
For performance, I want to be able to make single-context (well,
single-pixel-format-and-device) apps be able to directly call GL
functions through function pointers. Bake that into the ABI now so I
can get a release out the door and fix this up later.
This also fixes the lack of __stdcall annotation on the
PFNWHATEVERPROC typedefs.
This lets the compiler generate faster function calls (call through
function pointer, instead of call into a linker-generated stub func
containing jump to function pointer).
In addition to the failing testcase, there were a couple of
regressions in piglit's attribs test: one from glBegin_unwrapped vs
glBegin confusion in the __asm__ directives we were generating, and
one where the function pointers apparently were just getting mixed up
at application runtime.
This is going to change for macos and win32, and this will be easier
than trying to spread that logic through the python code and into the
generated code.
The dlopen bits are left in place, but the functions required the
types, and in the case of EGL, the types require that the platform
header actually exists.
This totally replaces the getprocaddress and dlsym code, which was
basically just stubs up until now. The is_glx/is_egl() is also
dropped -- they weren't doing anything, and the only false answer they
could give is if the dlopen were to fail.
I was thinking at one point that part of the build was going to
require not including the #defines from the generated code, but would
want these prototypes. It turns out that's not the case (and if it
is, I'll just wrap the #defines in an ifdef).
Unfortunately, for GLX 1.4+ entrypoints (just glxGetProcAddress
currently) or extensions, if there isn't a context bound then we don't
have a dpy and screen available to provide useful debug messages. Oh
well.
Emmanuele Bassi
Adam Jackson
Lyude Paul
Thomas Petazzoni
Chun-wei Fan
Yaron Cohen-Tal
Eric Anholt
Ryan Houdek