Since the Cogl 1.18 branch is actively maintained in parallel with the
master branch; this is a counter part to commit 1b83ef938fc16b which
re-licensed the master branch to use the MIT license.
This re-licensing is a follow up to the proposal that was sent to the
Cogl mailing list:
http://lists.freedesktop.org/archives/cogl/2013-December/001465.html
Note: there was a copyright assignment policy in place for Clutter (and
therefore Cogl which was part of Clutter at the time) until the 11th of
June 2010 and so we only checked the details after that point (commit
0bbf50f905)
For each file, authors were identified via this Git command:
$ git blame -p -C -C -C20 -M -M10 0bbf50f905..HEAD
We received blanket approvals for re-licensing all Red Hat and Collabora
contributions which reduced how many people needed to be contacted
individually:
- http://lists.freedesktop.org/archives/cogl/2013-December/001470.html
- http://lists.freedesktop.org/archives/cogl/2014-January/001536.html
Individual approval requests were sent to all the other identified authors
who all confirmed the re-license on the Cogl mailinglist:
http://lists.freedesktop.org/archives/cogl/2014-January
As well as updating the copyright header in all sources files, the
COPYING file has been updated to reflect the license change and also
document the other licenses used in Cogl such as the SGI Free Software
License B, version 2.0 and the 3-clause BSD license.
This patch was not simply cherry-picked from master; but the same
methodology was used to check the source files.
This adds COGL_PIXEL_FORMAT_RG_88 and COGL_TEXTURE_COMPONENTS_RG in
order to support two-component textures. The RG components for a
texture is only supported if COGL_FEATURE_ID_TEXTURE_RG is advertised.
This is only available on GL 3, GL 2 with the GL_ARB_texture_rg
extension or GLES with the GL_EXT_texture_rg extension. The RG pixel
format is always supported for images because Cogl can easily do the
conversion if an application uses this format to upload to a texture
with a different format.
If an application tries to create an RG texture when the feature isn't
supported then it will raise an error when the texture is allocated.
https://bugzilla.gnome.org/show_bug.cgi?id=712830
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit 568677ab3bcb62ababad1623be0d6b9b117d0a26)
Conflicts:
cogl/cogl-bitmap-packing.h
cogl/cogl-types.h
cogl/driver/gl/gl/cogl-driver-gl.c
tests/conform/test-read-texture-formats.c
tests/conform/test-write-texture-formats.c
This introduces the internal idea of texture loaders that track the
state for loading and allocating a texture. This defers a lot more work
until the texture is allocated.
There are several intentions to this change:
- provides a means for extending how textures are allocated without
requiring all the parameters to be supplied in a single _texture_new()
function call.
- allow us to remove the internal_format argument from all
_texture_new() apis since using CoglPixelFormat is bad way of
expressing the internal format constraints because it is too specific.
For now the internal_format arguments haven't actually been removed
but this patch does introduce replacement apis for controlling the
internal format:
cogl_texture_set_components() lets you specify what components your
texture needs when it is allocated.
cogl_texture_set_premultiplied() lets you specify whether a texture
data should be interpreted as premultiplied or not.
- Enable us to support asynchronous texture loading + allocation in the
future.
Of note, the _new_from_data() texture constructors all continue to
allocate textures immediately so that existing code doesn't need to be
adapted to manage the lifetime of the data being uploaded.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 6a83de9ef4210f380a31f410797447b365a8d02c)
Note: Compared to the original patch, the ->premultipled state for
textures isn't forced to be %TRUE in _cogl_texture_init since that
effectively ignores the users explicitly given internal_format which was
a mistake and on master that change should have been made in the patch
that followed. The gtk-doc comments for cogl_texture_set_premultiplied()
and cogl_texture_set_components() have also been updated in-line with
this fix.
Previously the private feature flags were stored in an enum and we
already had 31 flags. Adding the 32nd flag would presumably make it
add -2³¹ as one of the values which might cause problems. To avoid
this we'll just use an fixed-size array of longs and use indices for
the enum values like we do for the public features.
A slight complication with this is in the CoglDriverDescription where
we were previously using a static intialised value to describe the set
of features that the driver supports. We can't easily do this with the
flags array so instead the features are stored in a fixed-size array
of indices.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit d94cb984e3c93630f3c2e6e3be9d189672aa20f3)
Conflicts:
cogl/cogl-context-private.h
cogl/cogl-context.c
cogl/cogl-private.h
cogl/cogl-renderer.c
cogl/driver/gl/cogl-pipeline-opengl.c
cogl/driver/gl/gl/cogl-driver-gl.c
cogl/driver/gl/gl/cogl-pipeline-progend-fixed-arbfp.c
cogl/driver/gl/gles/cogl-driver-gles.c
cogl/driver/nop/cogl-driver-nop.c
Previously we would only add the #version pragma to shaders when
point sprite texture coordinates are enabled for a layer so that we
can access the gl_PointCoord builtin. However I don't think there's
any good reason not to just always request GLSL version 1.2 if it's
available. That way applications can always use gl_PointCoord without
having to enable point sprite texture coordinates.
This adds a glsl_version_to_use member to CoglContext which is used to
generate the #version pragma as part of the shader boilerplate. On
desktop GL this is set to 120 if version 1.2 is available, otherwise
it is left at 110. On GLES it is always left as 100.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit e4dfe8b07e8af111ecbcb0da20ff2a2875a2b5d0)
Conflicts:
cogl/driver/gl/gl/cogl-driver-gl.c
This adds a table of driver descriptions to cogl-renderer.c in order of
preference and when choosing what driver to use we now iterate the table
instead of repeating boilerplate checks. For handling the "default driver"
that can be specified when building cogl and handling driver overrides
there is a foreach_driver_description() that will make sure to iterate
the default driver first or if an override has been set then nothing but
the override will be considered.
This patch introduces some driver flags that let us broadly categorize
what kind of GL driver we are currently running on. Since there are
numerous OpenGL apis with different broad feature sets and new apis
may be introduced in the future by Khronos then we should tend to
avoid using the driver id to do runtime feature checking. These flags
provide a more stable quantity for broad feature checks.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit e07d0fc7441dddc3f0a2bc33a6a37d62ddc3efc0)
This adds a new function to enable per-vertex point size on a
pipeline. This can be set with
cogl_pipeline_set_per_vertex_point_size(). Once enabled the point size
can be set either by drawing with an attribute named
'cogl_point_size_in' or by writing to the 'cogl_point_size_out'
builtin from a snippet.
There is a feature flag which must be checked for before using
per-vertex point sizes. This will only be set on GL >= 2.0 or on GLES
2.0. GL will only let you set a per-vertex point size from GLSL by
writing to gl_PointSize. This is only available in GL2 and not in the
older GLSL extensions.
The per-vertex point size has its own pipeline state flag so that it
can be part of the state that affects vertex shader generation.
Having to enable the per vertex point size with a separate function is
a bit awkward. Ideally it would work like the color attribute where
you can just set it for every vertex in your primitive with
cogl_pipeline_set_color or set it per-vertex by just using the
attribute. This is harder to get working with the point size because
we need to generate a different vertex shader depending on what
attributes are bound. I think if we wanted to make this work
transparently we would still want to internally have a pipeline
property describing whether the shader was generated with per-vertex
support so that it would work with the shader cache correctly.
Potentially we could make the per-vertex property internal and
automatically make a weak pipeline whenever the attribute is bound.
However we would then also need to automatically detect when an
application is writing to cogl_point_size_out from a snippet.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit 8495d9c1c15ce389885a9356d965eabd97758115)
Conflicts:
cogl/cogl-context.c
cogl/cogl-pipeline-private.h
cogl/cogl-pipeline.c
cogl/cogl-private.h
cogl/driver/gl/cogl-pipeline-progend-fixed.c
cogl/driver/gl/gl/cogl-pipeline-progend-fixed-arbfp.c
cogl_framebuffer_add_fence creates a synchronisation fence, which will
invoke a user-specified callback when the GPU has finished executing all
commands provided to it up to that point in time.
Support is currently provided for GL 3.x's GL_ARB_sync extension, and
EGL's EGL_KHR_fence_sync (when used with OpenGL ES).
Signed-off-by: Daniel Stone <daniel@fooishbar.org>
Reviewed-by: Neil Roberts <neil@linux.intel.com>
Reviewed-by: Robert Bragg <robert@linux.intel.com>
https://bugzilla.gnome.org/show_bug.cgi?id=691752
(cherry picked from commit e6d37470da9294adc1554c0a8c91aa2af560ed9f)
GL_TEXTURE_MAX_LEVEL is not supported on GLES so we can't set it. It
looks like Mesa was letting us get away with this but on other drivers
it may cause errors. The enum is not defined in the GLES headers so it
was failing to compile unless the GL driver is also enabled.
The test-texture-mipmap-get-set test is now marked as n/a on GLES2
because it can't support limiting the sampled mipmaps.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit ba51c393818582b058f5f1e66cf8d13835ad10e5)
Conflicts:
tests/conform/test-conform-main.c
Previously when the context was initialised Cogl would query the
number of stencil bits and set a private feature flag to mark that it
can use the buffer for clipping if there was at least 3. The problem
with this is that the number of stencil bits returned by
GL_STENCIL_BITS depends on the currently bound framebuffer. This patch
adds an internal function to query the number of stencil bits in a
framebuffer and makes it use that instead when determining whether it
can push the clip using the stencil buffer.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit e928d21516a6c07798655341f4f0f8e3c1d1686c)
Consistent with how we lazily allocate framebuffers this patch allows us
to instantiate textures but still specify constraints and requirements
before allocating storage so that we can be sure to allocate the most
appropriate/efficient storage.
This adds a cogl_texture_allocate() function that is analogous to
cogl_framebuffer_allocate() which can optionally be called to explicitly
allocate storage and catch any errors. If this function isn't used
explicitly then Cogl will implicitly ensure textures are allocated
before the storage is needed.
It is generally recommended to rely on lazy storage allocation or at
least perform explicit allocation as late as possible so Cogl can be
fully informed about the best way to allocate storage.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 1fa7c0f10a8a03043e3c75cb079a49625df098b7)
Note: This reverts the cogl_texture_rectangle_new_with_size API change
that dropped the CoglError argument and keeps the semantics of
allocating the texture immediately. This is because Mutter currently
uses this API so we will probably look at updating this later once
we have a corresponding Mutter patch prepared. The other API changes
were kept since they only affected experimental api.
This moves the _cogl_texture_get_gl_format function from cogl-texture.c
to cogl-texture-gl.c and renames it _cogl_texture_gl_get_format.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit f8deec01eff7d8d9900b509048cf1ff1c86ca879)
This moves the direct use of GL in cogl-framebuffer.c for handling
cogl_framebuffer_read_pixels_into_bitmap() into
driver/gl/cogl-framebuffer-gl.c and adds a
->framebuffer_read_pixels_into_bitmap vfunc to CoglDriverVtable.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 2f893054d6754e6bc7983f061b27c7858f1a593c)
This remove cogl-internal.h in favour of using cogl-private.h. Some
things in cogl-internal.h were moved to driver/gl/cogl-util-gl-private.h
and the _cogl_gl_error_to_string function whose prototype was moved from
cogl-internal.h to cogl-util-gl-private.h has had its implementation
moved from cogl.c to cogl-util-gl.c
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 01cc82ece091aa3bec4c07fdd6bc9e5135fca573)
Both the texture drivers weren't handling errors correctly when a
CoglPixelBuffer was used to set the contents of an entire texture.
This was causing it to hit an assertion failure in the pixel buffer
tests.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit 888733d3c3b24080d2f136cedb3876a41312e4cf)
cogl_texture_set_region() and cogl_texture_set_region_from_bitmap() now
have a level argument so image data can be uploaded to a specific mipmap
level.
The prototype for cogl_texture_set_region was also updated to simplify
the arguments.
The arguments for cogl_texture_set_region_from_bitmap were reordered to
be consistent with cogl_texture_set_region with the source related
arguments listed first followed by the destination arguments.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 3a336a8adcd406b53731a6de0e7d97ba7932c1a8)
Note: Public API changes were reverted in cherry-picking this patch
‘Propagate’ was misspelled as ‘propogate’.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit 5fb4a6178c3e64371c01510690d9de1e8a740bde)
This adds a driver/gl/cogl-texture-gl.c file and moves some gl specific
bits from cogl-texture.c into it. The moved symbols were also given a
_gl_ infix and the calling code was updated accordingly.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 2c9e81de70cc02d72b1ce9013c49e39300a05b6a)
_cogl_bitmap_new_with_malloc_buffer() now takes a CoglError for throwing
exceptional errors and all callers have been updated to pass through
any application error pointer as appropriate.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 67cad9c0eb5e2650b75aff16abde49f23aabd0cc)
This allows apps to catch out-of-memory errors when allocating textures.
Textures can be pretty huge at times and so it's quite possible for an
application to try and allocate more memory than is available. It's also
very possible that the application can take some action in response to
reduce memory pressure (such as freeing up texture caches perhaps) so
we shouldn't just automatically abort like we do for trivial heap
allocations.
These public functions now take a CoglError argument so applications can
catch out of memory errors:
cogl_buffer_map
cogl_buffer_map_range
cogl_buffer_set_data
cogl_framebuffer_read_pixels_into_bitmap
cogl_pixel_buffer_new
cogl_texture_new_from_data
cogl_texture_new_from_bitmap
Note: we've been quite conservative with how many apis we let throw OOM
CoglErrors since we don't really want to put a burdon on developers to
be checking for errors with every cogl api call. So long as there is
some lower level api for apps to use that let them catch OOM errors
for everything necessary that's enough and we don't have to make more
convenient apis more awkward to use.
The main focus is on bitmaps and texture allocations since they
can be particularly large and prone to failing.
A new cogl_attribute_buffer_new_with_size() function has been added in
case developers need to catch OOM errors when allocating attribute buffers
whereby they can first use _buffer_new_with_size() (which doesn't take a
CoglError) followed by cogl_buffer_set_data() which will lazily allocate
the buffer storage and report OOM errors.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit f7735e141ad537a253b02afa2a8238f96340b978)
Note: since we can't break the API for Cogl 1.x then actually the main
purpose of cherry picking this patch is to keep in-line with changes
on the master branch so that we can easily cherry-pick patches.
All the api changes relating stable apis released on the 1.12 branch
have been reverted as part of cherry-picking this patch so this most
just applies all the internal plumbing changes that enable us to
correctly propagate OOM errors.
The core profile of GL3 has removed support for component-alpha
textures. Previously the GL3 driver would just ignore this and try to
create them anyway. This would generate a GL error on Mesa.
To fix this the GL texture driver will now create a GL_RED texture
when GL_ALPHA textures are not supported natively. It will then set a
texture swizzle using the GL_ARB_texture_swizzle extension so that the
alpha component will be taken from the red component of the texture.
The swizzle is part of the texture object state so it only needs to be
set once when the texture is created.
The ‘gen’ virtual function of the texture driver has been changed to
also take the internal format as a parameter. The GL driver will now
set the swizzle as appropriate here.
The GL3 driver now reports an error if the texture swizzle extension
is not available because Cogl can't really work properly without out
it. The extension is part of GL 3.3 so it is quite likely that it has
wide support from drivers. Eventually we could get rid of this
requirement if we have our own GLSL front-end and we could generate
the swizzle ourselves.
When uploading or downloading texture data to or from a
component-alpha texture, we can no longer rely on GL to do the
conversion. The swizzle doesn't have any effect on the texture data
functions. In these cases Cogl will now force an intermediate buffer
to be used and it will manually do the conversion as it does for the
GLES drivers.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit 32bacf81ebaa3be21a8f26af07d8f6eed6607652)
This adds a buffer method to map a subregion of the buffer. This works
using the GL_ARB_map_buffer_range extension. If the extension is not
available then it will fallback to using glMapBuffer to map the entire
buffer and then just add the offset to the returned pointer.
cogl_buffer_map() is now just a wrapper which maps the entire range of
the buffer. The driver backend functions have been renamed to
map_range and they now all take the offset and size arguments.
When the COGL_BUFFER_MAP_HINT_DISCARD hint is used and the map range
extension is available instead of using glBufferData to invalidate the
buffer it will instead pass the new GL_MAP_HINT_INVALIDATE_BUFFER
flag. There is now additionally a COGL_BUFFER_MAP_HINT_DISCARD_REGION
hint which can be used if the application only wants to discard the
small region that is mapped. glMapBufferRange is always used if it is
available even if the entire buffer is being mapped because it seems
more robust to pass those flags then to call glBufferData.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit 55ca02b5ca9cafc750251ec974e0d6a536cb80b8)
This adds a new CoglDriver for GL 3 called COGL_DRIVER_GL3. When
requested, the GLX, EGL and SDL2 winsyss will set the necessary
attributes to request a forward-compatible core profile 3.1 context.
That means it will have no deprecated features.
To simplify the explosion of checks for specific combinations of
context->driver, many of these conditionals have now been replaced
with private feature flags that are checked instead. The GL and GLES
drivers now initialise these private feature flags depending on which
driver is used.
The fixed function backends now explicitly check whether the fixed
function private feature is available which means the GL3 driver will
fall back to always using the GLSL progend. Since Rob's latest patches
the GLSL progend no longer uses any fixed function API anyway so it
should just work.
The driver is currently lower priority than COGL_DRIVER_GL so it will
not be used unless it is specificly requested. We may want to change
this priority at some point because apparently Mesa can make some
memory savings if a core profile context is used.
In GL 3, getting the combined extensions string with glGetString is
deprecated so this patch changes it to use glGetStringi to build up an
array of extensions instead. _cogl_context_get_gl_extensions now
returns this array instead of trying to return a const string. The
caller is expected to free the array.
Some issues with this patch:
• GL 3 does not support GL_ALPHA format textures. We should probably
make this a feature flag or something. Cogl uses this to render text
which currently just throws a GL error and breaks so it's pretty
important to do something about this before considering the GL3
driver to be stable.
• GL 3 doesn't support client side vertex buffers. This probably
doesn't matter because CoglBuffer won't normally use malloc'd
buffers if VBOs are available, but it might but worth making
malloc'd buffers a private feature and forcing it not to use them.
• GL 3 doesn't support the default vertex array object. This patch
just makes it create and bind a single non-default vertex array
object which gets used just like the normal default object. Ideally
it would be good to use vertex array objects properly and attach
them to a CoglPrimitive to cache the state.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit 66c9db993595b3a22e63f4c201ea468bc9b88cb6)
This adds a check for the glsl version during driver init which gets
stored in ctx->glsl_major and ctx->glsl_minor.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 9bde48bda6d602dd536c3536d56d2ff7545802c3)
As part of an on-going effort to be able to support non-opengl drivers
for Cogl this splits out the opengl specific code from cogl-buffer.c
into driver/gl/cogl-buffer-gl.c
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 4d7094a979ff2cbbe4054f4a44ca05fc41a9e447)
The buffer and bitmap _bind() functions are GL specific so to clarify
that, this patch adds a _gl infix to these functions, though it doesn't
yet move the implementations out into gl specific files.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 6371fbb9637d88ff187dfb6c4bcd18468ba44d19)
As part of an on-going effort to enable non-opengl drivers for Cogl this
splits out the opengl specific code in cogl-clip-stack.c into
cogl/driver/cogl-clip-stack-gl.c
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit acf989f1bb628282c53d1249b2e3fc6f6579f1e9)
As part of an on-going effort to enable non-opengl drivers for Cogl this
splits out the GL specific code in cogl-attribute.c into
cogl/driver/gl/cogl-attribute-gl.c
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 7e20c39c47fa176aa5062867ff273bc2c41a2f22)
This factors out all of the OpenGL specific code in cogl-texture-2d.c
into cogl-texture-2d-gl.c and where necessary adds indirection through
the CoglDriver vtable so that we can eventually start to experiment with
non-OpenGL backends for Cogl.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit ec57588671696bbe7ce714bdfe7324236146c9c0)
Although we use GLib internally in Cogl we would rather not leak GLib
api through Cogl's own api, except through explicitly namespaced
cogl_glib_ / cogl_gtype_ feature apis.
One of the benefits we see to not leaking GLib through Cogl's public API
is that documentation for Cogl won't need to first introduce the Glib
API to newcomers, thus hopefully lowering the barrier to learning Cogl.
This patch provides a Cogl specific typedef for reporting runtime errors
which by no coincidence matches the typedef for GError exactly. If Cogl
is built with --enable-glib (default) then developers can even safely
assume that a CoglError is a GError under the hood.
This patch also enforces a consistent policy for when NULL is passed as
an error argument and an error is thrown. In this case we log the error
and abort the application, instead of silently ignoring it. In common
cases where nothing has been implemented to handle a particular error
and/or where applications are just printing the error and aborting
themselves then this saves some typing. This also seems more consistent
with language based exceptions which usually cause a program to abort if
they are not explicitly caught (which passing a non-NULL error signifies
in this case)
Since this policy for NULL error pointers is stricter than the standard
GError convention, there is a clear note in the documentation to warn
developers that are used to using the GError api.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit b068d5ea09ab32c37e8c965fc8582c85d1b2db46)
Note: Since we can't change the Cogl 1.x api the patch was changed to
not rename _error_quark() functions to be _error_domain() functions and
although it's a bit ugly, instead of providing our own CoglError type
that's compatible with GError we simply #define CoglError to GError
unless Cogl is built with glib disabled.
Note: this patch does technically introduce an API break since it drops
the cogl_error_get_type() symbol generated by glib-mkenum (Since the
CoglError enum was replaced by a CoglSystemError enum) but for now we
are assuming that this will not affect anyone currently using the Cogl
API. If this does turn out to be a problem in practice then we would be
able to fix this my manually copying an implementation of
cogl_error_get_type() generated by glib-mkenum into a compatibility
source file and we could also define the original COGL_ERROR_ enums for
compatibility too.
Note: another minor concern with cherry-picking this patch to the 1.14
branch is that an api scanner would be lead to believe that some APIs
have changed, and for example the gobject-introspection parser which
understands the semantics of GError will not understand the semantics of
CoglError. We expect most people that have tried to use
gobject-introspection with Cogl already understand though that it is not
well suited to generating bindings of the Cogl api anyway and we aren't
aware or anyone depending on such bindings for apis involving GErrors.
(GnomeShell only makes very-very minimal use of Cogl via the gjs
bindings for the cogl_rectangle and cogl_color apis.)
The main reason we have cherry-picked this patch to the 1.14 branch
even given the above concerns is that without it it would become very
awkward for us to cherry-pick other beneficial patches from master.
As part of an effort towards being able to write non-opengl based
backends for Cogl this moves most of the opengl specific code under
drivers/gl. drivers/gl and drivers/gles have been moved to
drivers/gl/gl and drivers/gl/es respectively.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 7dc482facb0a265c7f48660079e7e12dd7a2813e)
