This new API lets the loader examine DRI level extensions provided by the
driver in a forward compatible manner.
Much of the churn in the DRI interface is adding support for new
extensions or removing old, unused extensions. This new extension
mechanism lets the loader query the extensions provided by the driver
and implement the extensions it knows about. Deprecating extensions
is done by not exporting that extension in the list, which doesn't
require keeping old function pointers around to preserve ABI.
The entrypoints take a mix of __DRIscreen * and void * (screen private)
arguments (similarly for contexts and drawables). This patch does away
with passing the private void pointer and always only passes the fully
typed __DRIscreen pointer and always as the first argument.
This makes the interface more consistent and increases type safety, and
catches a bug where we would pass a screen private to DRIdrawable::getSBC.
The screenConfigs field of __DRIscreen points back to the containing
__GLXscreenConfigs struct. This is a serious abstraction violation; it
assumes that the loader is libGL and that there *is* a __GLXscreenConfigs
type in the loader.
Using the containerOf macro, we can get from the __DRIscreen pointer to
the containing __GLXscreenConfigs struct, at a place in the stack
where the above is a valid assumption. Besides, the __DRI* structs shouldn't
hold state other than the private pointer.
As for createDrawable and destroyDrawable, these functions immediately
upon entry to driCreateNewContext and immediately before exit from
driDestroyContext. Instead of passing function pointers back and forth
just obtain the drm_context_t prior to calling DRIscreen::createNewContext
and pass it as a parameter.
This change also lets us keep the DRI context XID in the libGL loader only.
All the DRI driver did was call the createDrawable callback immediately
upon entry to DRIscreen::createNewDrawable to get the drm_drawable_t.
We can just call that before calling into the DRI driver and pass the
returned drm_drawable_t as an argument to the DRI entry point.
Likewise for destroyDrawable.
Also, DRIdrawablePrivate::draw isn't used anywhere, and since the
driver no longer needs the XID of the drawable we can now drop that.
Many DRI entry points took a __DRInativeDisplay pointer and a screen
index as arguments. The only use for the native display pointer was to
pass it back to the loader when looking up the __DRIscreen for the given
screen index.
Instead, let's just pass in the __DRIscreen pointer directly, which
let's drop the __DRInativeDisplay type and the getScreen function.
The assumption is now that the loader will be able to retrieve context
from the __DRIscreen pointer when necessary.
With this, tools like ximagesrc in gstreamer correctly see updates from GL
rendering. Support requires that the Xdamage library be current (but will be
disabled if not present) plus a new X Server with support for the new
XDamagePost request. libGL now has a new interface version, and also links
against libXdamage and libXfixes to support it, but backwards compatibility
is retained.
Currently, all drivers report damage at SwapBuffers time through common code --
front buffer rendering doesn't result in damage being reported. Also, the
damage is against the root window, as our drivers don't yet render to backing
store when they should (composited environments).
_glapi_add_entrypoint has been replaced by a new routine called
_glapi_add_dispatch. This new routine dynamically assignes dispatch offsets
to functions added. This allows IHVs to add support for extension functions
that do not have assigned dispatch offsets.
It also means that a driver has no idea what offset will be assigned to a
function. The vast majority of the changes in this commit account for that.
An additional table, driDispatchRemapTable, is added. Functions not in the
Linux OpenGL ABI (i.e., anything not in GL 1.2 + ARB_multitexture) has a
fixed offset in this new table. The entry in this table specifies the
offset in of the function in the real dispatch table.
The internal interface was also bumped from version 20050725 to 20050727.
This has been tested with various programs in progs/demos on:
radeon (Radeon Mobility M6)
r128 (Rage 128 Pro)
mga (G400)
that are currently obtained via glXGetProcAddress and all of the XF86DRI
functions are replaced with a funciton table. This table will be passed to
__driCreateNewScreen.
One of the functions in the table is getProcAddress. This allows some
loaders to expose functionality not in all loaders. This will be immediatly
used for glxEnableExtension (formerly known to drivers as
__glXScrEnableExtension). libGL (and in the future libglx) expose this
function so that drivers can enable GLX extensions. libEGL should exposed
eglEnableExtension to enable EGL extensions. The same function cannot be
used for both because the extensions have different names and (possibly)
different semantics. Drivers can optionally use one, both, or neither.
The key parts are in the __DRIinterfaceMethodsRec structure in
dri_interface.h. A pointer to one of these structures is passed into
__driCreateNewScreen. Because of this, the version of the API is bumped to
20050725. Since the previous version(s) were never in a release, their
existance is erased.
I was actually a little surprised by how much code this cuts from the
drivers. A lot of glXGetProcAddress calls disappear, and a lot of
version checks go with them. Nice.
The one thing I'm not sure of is removing __glXInitialize. For some
reason that function was in the glXGetProcAddress table, but *nothing*
in the Mesa tree used it. Did something with DRI conf. use this
function? It seems odd...
(from glxclient.h) with PFNCREATENEWSCREEN (from dri_interface.h).
Remove the prototype for __driCreateScreen and fix the prototype for
__driCreateNewScreen (append the API version) in dri_interface.h.
1,402 lines of code to be removed from Mesa (drivers and libGL). The
big winner is dri_util.c.
Primary changes are:
1. Remove all "deprecated" entry-points from the various structures in
dri_interface.h.
2. Rename the remaining fields to removed "version numbers." So,
bindContext3 becomes bindContext. Functions with "New" in the name
(e.g., CreateNewContext) were *not* changed, but that is an option.
Having "New" in the name is less annoying to me than having "3" in the name.
3. Remove all compatibility code that handles cases where the driver or
the loader is too old to support the latest interfaces.
4. Append the API version to the __driCreateNewScreen function name.
This is currently done by hand. In the future (i.e., the next time we
make an incompatible change to the interface) we'll want to come up with
a better way to do this. This prevents old loaders from being able to load
new (incompatible) drivers.
5. Bump the API version to 20050722. All drivers (by way of dri_util.c)
require this version.
6. All drivers are *required* to expose GLX_SGIX_fbconfig and
GLX_OML_swap_method (or the moral equivalents). Support for these
functions in implicit in the use of the "new" interface.
7. Some cases still exist that need to be compiled differently in a loader
or core Mesa versus in a driver. These are identified by the define
IN_DRI_DRIVER.
XF86DRIDestroyDrawable are all called directly from DRI drivers using
the new interface. Therefore, prototypes, using available datatypes,
must be available in dri_interface.h. Since the prototypes are
available there, xf86dri.h is no longer needed for
DRI_NEW_INTERFACE_ONLY builds.
interface that are not *strictly* part of the old interface were
changed. Replace GetDrawableInfo type (dri_util.h) with
PFNGLXGETDRAWABLEINFOPROC (dri_interface.h). Wrap __driCreateScreen
(in drivers that use the new interface) with '#ifndef
DRI_NEW_INTERFACE_ONLY'.
Kristian Høgsberg
Kristian Høgsberg
Michel Dänzer
Eric Anholt
Brian Paul
Ian Romanick
Alan Hourihane
Jon Smirl
Keith Whitwell