Commit Graph

32 Commits

Author SHA1 Message Date
Jasper St. Pierre
0d91085193 cogl-winsys-egl-kms: Add cogl_kms_renderer_set_kms_fd
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 7bc7ea4cb5e8134a3aeed9615477f4152b558509)

Conflicts:
	cogl/winsys/cogl-winsys-egl-kms.c
2014-03-12 17:29:21 +00:00
Robert Bragg
a0441778ad This re-licenses Cogl 1.18 under the MIT license
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.
2014-02-22 02:02:53 +00:00
Neil Roberts
c5644723f8 Use COGL_FLAGS_* for the context's private feature flags
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
2013-11-28 18:12:22 +00:00
Neil Roberts
e7b50a6cba renderer: Only check certain constraints when selecting a driver
Only COGL_RENDERER_CONSTRAINT_SUPPORTS_COGL_GLES2 affects the driver
selection and all of the the other constraints are only relevant to
the winsys selection. However Cogl was trying to apply all of the
constraints to the driver selection which meant that if any other
constraint was specified then it would always fail. This patch makes
the driver selection filter out all other constraints based on a mask
defined in cogl-renderer-private.h.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit f07febc8913b97fb828e7f2cc2857813af2d3657)
2013-08-23 16:49:59 +01:00
Robert Bragg
34658ea057 generalize driver description and selection
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)
2013-08-23 14:51:43 +01:00
Neil Roberts
3d9eaef3ac wayland: Add API to prevent Cogl from dispatching the wayland display
This adds cogl_wayland_renderer_set_event_dispatch_enabled() which can
be used to prevent Cogl from adding the socket for the Wayland display
to its list of file descriptors to poll. This can be used in
applications that want to integrate Cogl with existing code that is
reading from the Wayland socket itself.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit f5b8d98676ab3e90ad80459019c737ec2ff90aa4)
2013-07-09 15:46:46 +01:00
Neil Roberts
18ce7ad7f5 Get rid of the foreign shell and compositor APIs
The Wayland 1.0 protocol supports multiple independent components querying the
available interfaces by retreiving their own wl_registry object so the
application doesn't need to pass them down anymore.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit 8ca36a1d1ab7236fec0f4d7b7361ca96e14c32be)
2013-07-09 15:46:46 +01:00
Neil Roberts
534e535a28 Use the Wayland embedded linked list implementation instead of BSD's
This removes cogl-queue.h and adds a copy of Wayland's embedded list
implementation. The advantage of the Wayland model is that it is much
simpler and so it is easier to follow. It also doesn't require
defining a typedef for every list type.

The downside is that there is only one list type which is a
doubly-linked list where the head has a pointer to both the beginning
and the end. The BSD implementation has many more combinations some of
which we were taking advantage of to reduce the size of critical
structs where we didn't need a pointer to the end of the list.

The corresponding changes to uses of cogl-queue.h are:

• COGL_STAILQ_* was used for onscreen the list of events and dirty
  notifications. This makes the size of the CoglContext grow by one
  pointer.

• COGL_TAILQ_* was used for fences.

• COGL_LIST_* for CoglClosures. In this case the list head now has an
  extra pointer which means CoglOnscreen will grow by the size of
  three pointers, but this doesn't seem like a particularly important
  struct to optimise for size anyway.

• COGL_LIST_* was used for the list of foreign GLES2 offscreens.

• COGL_TAILQ_* was used for the list of sub stacks in a
  CoglMemoryStack.

• COGL_LIST_* was used to track the list of layers that haven't had
  code generated yet while generating a fragment shader for a
  pipeline.

• COGL_LIST_* was used to track the pipeline hierarchy in CoglNode.

The last part is a bit more controversial because it increases the
size of CoglPipeline and CoglPipelineLayer by one pointer in order to
have the redundant tail pointer for the list head. Normally we try to
be very careful about the size of the CoglPipeline struct. Because
CoglPipeline is slice-allocated, this effectively ends up adding two
pointers to the size because GSlice rounds up to the size of two
pointers.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit 13abf613b15f571ba1fcf6d2eb831ffc6fa31324)

Conflicts:
	cogl/cogl-context-private.h
	cogl/cogl-context.c
	cogl/driver/gl/cogl-pipeline-fragend-glsl.c
	doc/reference/cogl-2.0-experimental/Makefile.am
2013-06-13 13:45:47 +01:00
Neil Roberts
4543ed6ac3 win32: Automatically process windows messages when using a GMainLoop
Previously the WGL winsys was expecting the application to send all
windows messages to Cogl via the cogl_win32_renderer_handle_event
function. When using a GLib main loop we can make this work
transparently to the application with a GSource for the magic
G_WIN32_MSG_HANDLE file descriptor. That causes the GMainLoop to wake
up whenever a message is available.

This patch makes the WGL winsys add that magic value as a source fd.
This will only have any meaning if the application is using glib, but
it shouldn't matter because the cogl_poll_renderer_get_info function
is documented to only work on Unix-based winsys's anyway.

This patch is an API break because by default Cogl will now start
stealing all of the Windows messages. Something like Clutter that wants to handle
its own event retrieval would now need to call
cogl_win32_renderer_set_event_retrieval_enabled to stop Cogl from
stealing the events.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit 99a7f84d7149f24f3e86c5d3562f9f2632ff6df8)
2013-05-30 13:41:44 +01:00
Robert Bragg
95a41e177a Associate check and dispatch funcs with poll fds
Instead of driving event dispatching through a per winsys poll_dispatch
vfunc its now possible to associate a check and dispatch function with
each file descriptor that is registered for polling. This means we can
remove the winsys get_dispatch_timeout and poll_dispatch vfuncs and it
also makes it easier for more orthogonal internal components to add file
descriptors for polling to the mainloop.

Reviewed-by: Neil Roberts <neil@linux.intel.com>

(cherry picked from commit 627947622df36dd529b9dc60a3ae9e6083532b19)
2013-04-30 16:39:31 +01:00
Robert Bragg
e3975d1711 Add api for queuing idle callback internally
This adds a _cogl_poll_renderer_add_idle api that can be used internally
for queuing an idle callback without needing to make any assumption
about the system mainloop that is being used. This is now used to avoid
having the _cogl_poll_renderer_dispatch() directly check for all kinds of
events to dispatch, and to avoid having the winsys dispatch vfuncs need
to directly know about CoglContext. This means we can now avoid having a
back reference from CoglRenderer to the CoglContext.

Reviewed-by: Neil Roberts <neil@linux.intel.com>

(cherry picked from commit a1e169f18f4257caec58760adccfe4ec09b9805d)
2013-04-30 16:39:31 +01:00
Robert Bragg
ed90c6fed9 Move event polling into CoglRenderer
This updates the cogl_poll_ apis to allow dispatching events before we
have a CoglContext and to also enables pollfd state to be changed in a
more add-hoc way by different Cogl components by replacing the
winsys->get_poll_info with _cogl_poll_renderer_add/remove_fd functions
and a winsys->get_dispatch_timeout vfunc.

One of the intentions here is that applications should be able to run
their mainloop before creating a CoglContext to potentially get events
relating to CoglOutputs.

Reviewed-by: Neil Roberts <neil@linux.intel.com>

(cherry picked from commit 667e58c9cb2662aef5f44e580a9eda42dc8d0176)
2013-04-30 16:39:31 +01:00
Neil Roberts
f8108751a5 sdl: Use a 32-bit type to store the user event type number
In SDL1 the event type numbers were a single byte so there were only
reserving a byte to store the application's chosen type in
CoglRenderer. However in SDL2 they are a Uint32 and SDL_USEREVENT is
0x8000 so if the application was using that then Cogl would actually
end up posting event type 0.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit 39c9177776ac601a92c6f4112558464af6968ea0)
2013-02-03 10:07:47 +01:00
Owen W. Taylor
88d8bd84f2 Add CoglOutput and track for the GLX backend
The CoglOutput object represents one output such as a monitor or
laptop panel, with information about attributes of the output such as
the position of the output within the global coordinate space, and
the refresh rate.

We don't yet publically export the ability to get output information but
we track it for the GLX backend, where we'll use it to track the refresh
rate.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit d7ef9d8d71488d0e6874f1ffc6e48700d5c82a31)
2013-01-30 19:56:45 +00:00
Robert Bragg
36c85da3b8 Remove cogl-internal.h
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)
2013-01-22 17:48:17 +00:00
Robert Bragg
ce5d06afe1 framebuffer: split GL code out from cogl-framebuffer.c
This splits out most of the OpenGL specific code from cogl-framebuffer.c
into cogl-framebuffer-gl.c and extends the CoglDriverVtable interface
for cogl-framebuffer.c to use.

There are hopes to support several different backends for Cogl
eventually to hopefully get us closer to the metal so this makes some
progress in organizing which parts of Cogl are OpenGL specific so these
parts can potentially be switched out later.

The only remaining use of OpenGL still in cogl-framebuffer.c is to
handle cogl_framebuffer_read_pixels.
2013-01-18 10:53:29 +00:00
Neil Roberts
df77e8565e Don't use eglGetProcAddress to retrieve core functions
According to the EGL spec, eglGetProcAddress should only be used to
retrieve extension functions. It also says that returning non-NULL
does not mean the extension is available so you could interpret this
as saying that the function is allowed to return garbage for core
functions. This seems to happen at least for the Android
implementation of EGL.

To workaround this the winsys's are now passed down a flag to say
whether the function is from the core API. This information is already
in the gl-prototypes headers as the minimum core GL version and as a
pair of flags to specify whether it is available in core GLES1 and
GLES2. If the function is in core the EGL winsys will now avoid using
eglGetProcAddress and always fallback to querying the library directly
with the GModule API.

The GLX winsys is left alone because glXGetProcAddress apparently
supports querying core API and extension functions.

The WGL winsys could ideally be changed because wglGetProcAddress
should also only be used for extension functions but the situation is
slightly different because WGL considers anything from GL > 1.1 to be
an extension so it would need a bit more information to determine
whether to query the function directly from the library.

The SDL winsys is also left alone because it's not as easy to portably
determine which GL library SDL has chosen to load in order to resolve
the symbols directly.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit 72089730ad06ccdd38a344279a893965ae68cec1)

  Since we aren't able to break API on the 1.12 branch
  cogl_get_proc_address is still supported but isn't easily able to
  determine whether the given name corresponds to a core symbol or
  not.  For now we just assume the symbol being queried isn't part
  of the core GL api and update the documentation accordingly.
2012-08-06 14:27:45 +01:00
Robert Bragg
54735dec84 Switch use of primitive glib types to c99 equivalents
The coding style has for a long time said to avoid using redundant glib
data types such as gint or gchar etc because we feel that they make the
code look unnecessarily foreign to developers coming from outside of the
Gnome developer community.

Note: When we tried to find the historical rationale for the types we
just found that they were apparently only added for consistent syntax
highlighting which didn't seem that compelling.

Up until now we have been continuing to use some of the platform
specific type such as gint{8,16,32,64} and gsize but this patch switches
us over to using the standard c99 equivalents instead so we can further
ensure that our code looks familiar to the widest range of C developers
who might potentially contribute to Cogl.

So instead of using the gint{8,16,32,64} and guint{8,16,32,64} types this
switches all Cogl code to instead use the int{8,16,32,64}_t and
uint{8,16,32,64}_t c99 types instead.

Instead of gsize we now use size_t

For now we are not going to use the c99 _Bool type and instead we have
introduced a new CoglBool type to use instead of gboolean.

Reviewed-by: Neil Roberts <neil@linux.intel.com>

(cherry picked from commit 5967dad2400d32ca6319cef6cb572e81bf2c15f0)
2012-08-06 14:27:39 +01:00
Robert Bragg
9a1f1df83f Rework sdl integration api
This re-works the SDL integration api to simplify the integration for
application developers and also allow Cogl to know when the application
is about to go idle waiting for events so it can perform idle
book-keeping work.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
2012-04-12 12:31:46 +01:00
Robert Bragg
be237cc2b7 renderer: Adds getters/setters for driver preference
This adds api for explicitly choosing what underlying driver cogl should
use internally for rendering as well as api for querying back what
driver is actually in use.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
2012-02-24 14:42:31 +00:00
Robert Bragg
a8513c1d77 renderer: Adds api to add/remove selection constraints
This allows applications to specify certain constraints that feed into
the process of selecting a CoglRenderer backend. For example
applications might depend on x11 for handling input and so they require
a backend that's also based on x11.
2012-01-16 18:27:19 +00:00
Neil Roberts
181b875a3d xlib: Internally retrieve XEvents
Previously we relied on the application to send all X events through
Cogl using cogl_xlib_renderer_handle_event. This breaks the
abstraction that an application shouldn't need to know what winsys
Cogl is using. Now that we have main loop integreation in Cogl, the
Xlib-based winsys's can report that Cogl needs to block on the file
descriptor of the X connection and it can manually handle the
events.

The event retrieval can be disabled by an application if it calls the
new cogl_xlib_renderer_set_event_retrieval_enabled() function. The
event retrieval will also automatically be disabled if the application
sets a foreign display.

Reviewed-by: Robert Bragg <robert@linux.intel.com>
2012-01-05 13:40:24 +00:00
Robert Bragg
14ddbd980b wayland: Add api to set a foreign shell
Since the wayland protocol doesn't currently provide a way to
retrospectively query the interfaces that get notified when a client
first connects then when using a foreign display with Cogl then we also
need api for telling cogl what compositor and shell objects to use. We
already had api for setting a foreign compositor so this patch just adds
api for setting a foreign shell.

This patch also adds documentation for all the wayland specific apis.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
2011-12-07 15:53:05 +00:00
Philip Withnall
d51c3c423e Fix testing of undefined macro constants to check for definedness instead
Reviewed-By: Robert Bragg <robert@linux.intel.com>
2011-07-27 18:46:36 +01:00
Neil Roberts
d259a87602 Don't use the 'NULL' GModule to resolve GL symbols
Previously, _cogl_get_proc_address had a fallback to resolve the
symbol using g_module_open(NULL) to get the symbol from anywhere in
the address space. The EGL backend ends up using this on some drivers
because eglGetProcAddress isn't meant to return a pointer for core
functions. This causes problems if something in the process is linking
against a different GL library, for example Cairo may be linking
against libGL itself. In this case it may end up resolving symbols
from the GL library even if GLES is being used.

This patch removes the fallback. The EGL version now has its own
fallback instead which passes the existing libgl_module from the
renderer to g_module_symbol so that it should only get symbols from
that library or its dependency chain. The GLX and WGL winsys only call
glXGetProcAddress and wglGetProcAddress. The stub winsys does however
continue using the global symbol lookup.

The internal _cogl_get_proc_address function has been renamed to
_cogl_renderer_get_proc_address because it needs a connected renderer
to work so it could be considered to be a renderer method. The pointer
to the renderer is passed down to the winsys backends so that it can
use the data attached to the renderer to get the module pointers.

https://bugzilla.gnome.org/show_bug.cgi?id=655412

Reviewed-by: Robert Bragg <robert@linux.intel.com>
2011-07-27 16:10:02 +01:00
Neil Roberts
b2e735ff7f Dynamically load the GL or GLES library
The GL or GLES library is now dynamically loaded by the CoglRenderer
so that it can choose between GL, GLES1 and GLES2 at runtime. The
library is loaded by the renderer because it needs to be done before
calling eglInitialize. There is a new environment variable called
COGL_DRIVER to choose between gl, gles1 or gles2.

The #ifdefs for HAVE_COGL_GL, HAVE_COGL_GLES and HAVE_COGL_GLES2 have
been changed so that they don't assume the ifdefs are mutually
exclusive. They haven't been removed entirely so that it's possible to
compile the GLES backends without the the enums from the GL headers.

When using GLX the winsys additionally dynamically loads libGL because
that also contains the GLX API. It can't be linked in directly because
that would probably conflict with the GLES API if the EGL is
selected. When compiling with EGL support the library links directly
to libEGL because it doesn't contain any GL API so it shouldn't have
any conflicts.

When building for WGL or OSX Cogl still directly links against the GL
API so there is a #define in config.h so that Cogl won't try to dlopen
the library.

Cogl-pango previously had a #ifdef to detect when the GL backend is
used so that it can sneakily pass GL_QUADS to
cogl_vertex_buffer_draw. This is now changed so that it queries the
CoglContext for the backend. However to get this to work Cogl now
needs to export the _cogl_context_get_default symbol and cogl-pango
needs some extra -I flags to so that it can include
cogl-context-private.h
2011-07-11 12:57:38 +01:00
Robert Bragg
3b64a439f0 replace public native_event APIs with typesafe APIs
This adds Xlib and Win32 typesafe replacements for
cogl_renderer_handle_native_event, cogl_renderer_add_native_filter,
cogl_renderer_remove_native_filter. The old functions are kept as an
implementation detail so we can share code.

Signed-off-by: Neil Roberts <neil@linux.intel.com>
2011-06-30 14:33:13 +01:00
Robert Bragg
b3a105c576 renderer: Expose winsys ID setter/getters
This adds API to let you override the choice of Cogl's winsys backend.
Previously it was only possible to override the winsys using the
COGL_RENDERER environment variable, but it's useful for something like
Clutter to be able to control the winsys via API without needing
environment variable tricks. This also adds API to query back the
winsys chosen by Cogl, in case you don't set an explicit override.

Signed-off-by: Neil Roberts <neil@linux.intel.com>
2011-06-30 14:33:11 +01:00
Robert Bragg
e8b83f2880 Adds wayland support to the cogl EGL winsys
Wayland now supports integration via standard eglSurfaces which makes it
possible to share more code with other EGL platforms. (though at some
point cogl-winsys-egl.c really needs to gain a more formal
CoglEGLPlatform abstraction so we can rein back on the amount of #ifdefs
we have.)
2011-05-10 16:36:40 +01:00
Robert Bragg
dc7383b714 Add a vtable of indirection to the winsys code
So that we can dynamically select what winsys backend to use at runtime
we need to have some indirection to how code accesses the winsys instead
of simply calling _cogl_winsys* functions that would collide if we
wanted to compile more than one backend into Cogl.
2011-05-05 14:46:01 +01:00
Neil Roberts
f6ae9decaa cogl-renderer: Move the XEvent filters to be generic for all renderers
Instead of having cogl_renderer_xlib_add_filter and friends there is
now cogl_renderer_add_native_filter which can be used regardless of
the backend. The callback function for the filter now just takes a
void pointer instead of an XEvent pointer which should be interpreted
differently depending on the backend. For example, on Xlib it would
still be an XEvent but on Windows it could be a MSG. This simplifies
the code somewhat because the _cogl_xlib_add_filter no longer needs to
have its own filter list when a stub renderer is used because there is
always a renderer available.

cogl_renderer_xlib_handle_event has also been renamed to
cogl_renderer_handle_native_event. This just forwards the event on to
all of the listeners. The backend renderer is expected to register its
own event filter if it wants to process the events in some way.
2011-04-20 18:17:06 +01:00
Robert Bragg
bcd97f35ea Adds renderer,display,onscreen-template and swap-chain stubs
As part of the process of splitting Cogl out as a standalone graphics
API we need to introduce some API concepts that will allow us to
initialize a new CoglContext when Clutter isn't there to handle that for
us...

The new objects roughly in the order that they are (optionally) involved
in constructing a context are: CoglRenderer, CoglOnscreenTemplate,
CoglSwapChain and CoglDisplay.

Conceptually a CoglRenderer represents a means for rendering.  Cogl
supports rendering via OpenGL or OpenGL ES 1/2.0 and those APIs are
accessed through a number of different windowing APIs such as GLX, EGL,
SDL or WGL and more. Potentially in the future Cogl could render using
D3D or even by using libdrm and directly banging the hardware. All these
choices are wrapped up in the configuration of a CoglRenderer.

Conceptually a CoglDisplay represents a display pipeline for a renderer.
Although Cogl doesn't aim to provide a detailed abstraction of display
hardware, on some platforms we can give control over multiple display
planes (On TV platforms for instance video content may be on one plane
and 3D would be on another so a CoglDisplay lets you select the plane
up-front.)

Another aspect of CoglDisplay is that it lets us negotiate a display
pipeline that best supports the type of CoglOnscreen framebuffers we are
planning to create. For instance if you want transparent CoglOnscreen
framebuffers then we have to be sure the display pipeline wont discard
the alpha component of your framebuffers. Or if you want to use
double/tripple buffering that requires support from the display
pipeline.

CoglOnscreenTemplate and CoglSwapChain are how we describe our default
CoglOnscreen framebuffer configuration which can affect the
configuration of the display pipeline.

The default/simple way we expect most CoglContexts to be constructed
will be via something like:

 if (!cogl_context_new (NULL, &error))
   g_error ("Failed to construct a CoglContext: %s", error->message);

Where that NULL is for an optional "display" parameter and NULL says to
Cogl "please just try to do something sensible".

If you want some more control though you can manually construct a
CoglDisplay something like:

 display = cogl_display_new (NULL, NULL);
 cogl_gdl_display_set_plane (display, plane);
 if (!cogl_display_setup (display, &error))
   g_error ("Failed to setup a CoglDisplay: %s", error->message);

And in a similar fashion to cogl_context_new() you can optionally pass
a NULL "renderer" and/or a NULL "onscreen template" so Cogl will try to
just do something sensible.

If you need to change the CoglOnscreen defaults you can provide a
template something like:
  chain = cogl_swap_chain_new ();
  cogl_swap_chain_set_has_alpha (chain, TRUE);
  cogl_swap_chain_set_length (chain, 3);

  onscreen_template = cogl_onscreen_template_new (chain);
  cogl_onscreen_template_set_pixel_format (onscreen_template,
                                           COGL_PIXEL_FORMAT_RGB565);

  display = cogl_display_new (NULL, onscreen_template);
  if (!cogl_display_setup (display, &error))
    g_error ("Failed to setup a CoglDisplay: %s", error->message);
2011-04-11 17:54:35 +01:00