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.
Link to SDL.lib and SDLmain.lib if Cogl was built with the SDL winsys.
Recent changes to the SDL winsys introduced a direct dependency to
SDLmain.lib (and hence SDL.lib) when programs are built, causing linker
errors to appear when any programs using cogl (with the SDL winsys built
in) are built.
Since we cannot determine whether a Cogl build is built with the SDL winsys
at build time easily, we could use #pragma comment (lib, ...) whenever
cogl-sdl.h is included by cogl.h so that SDLmain.lib and SDL.lib is linked
into the resulting binary, so that the program can link and run correctly.
This does not add any external dependencies as the Cogl DLL already depends
on SDL.dll when it is built with the SDL winsys.
The first argument has been removed from the function. Update the
example accordingly.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit 06e47af3144565bdf85abf8ae561c7ceeafa2cbc)
This adds an alternate version of the SDL winsys using the SDL 2 API.
The two versions are mutually exclusive and share the same
CoglWinsysID. Version 2 of SDL fits a little bit better with Cogl
because it supports multiple windows and the video subsystem can be
initialised entirely independently of the rest of the subsystems.
The SDL2 winsys creates an invisible dummy window in order to bind the
GL context after creating the Cogl display. This is similar to how the
X11 winsys's work.
SDL2 seems to support compiling with support for both GL and GLES.
However there doesn't seem to be a way to select between the two
backends outside of SDL. In fact if you do compile them both in it
seems to break down because it will always try to use the window
system functions from the GLES backend because those are filled in
second in the vtable. However when creating the window it will always
prefer to use the GL function to choose a visual. This function gets
confused because the GL backend has not been initialised at that
point. The Cogl backend therefore just leaves it up to SDL to pick a
sensible backend. It will then verify that it picked a GL library
which matches the Cogl driver by checking the string from
glGetString(GL_VERSION).
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit 6cb5ab41355e7bfe28f367cf4afa39a7afcfeec2)
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)
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>
