If we have to copy the bitmap to do the premultiplication then we were
previously using the rowstride of the source image as the rowstride
for the new image. This is wasteful if the source image is a subregion
of a larger image which would make it use a large rowstride. If we
have to copy the data anyway we might as well compact it to the
smallest rowstride. This also prevents the copy from reading past the
end of the last row of pixels.
An internal function called _cogl_bitmap_copy has been added to do the
copy. It creates a new bitmap with the smallest possible rowstride
rounded up the nearest multiple of 4 bytes. There may be other places
in Cogl that are currently assuming we can read height*rowstride of
the source buffer so they may want to take advantage of this function
too.
http://bugzilla.clutter-project.org/show_bug.cgi?id=2491
We now make _cogl_buffer_bind return a base pointer for the bound buffer
which can be used with OpenGL. The pointer will be NULL for GPU based
buffers or may point to an malloc'd buffer. Since OpenGL expects an
offset instead of a pointer when dealing with buffer objects this means
we can handle fallback malloc buffers and GPU buffers in a consistent
way.
All the macros get used for are to |= (a new flag bit), &= ~(a flag bit)
or use the & operator to test if a flag bit is set. I haven't found the
code more readable with these macros, but several times now I've felt
the need to double check if these macros do anything else behind the
hood or I've forgotten what flags are available so I've had to go to the
macro definition to see what the full enum names are for the flags (the
macros use symbol concatenation) so I can search for the definition of
all the flags. It turns out they are defined next to the macro so you
don't have to search far, but without the macro that wouldn't have been
necessary.
The more common use of the _IS_SET macro is actually more concise
expanded and imho since it doesn't hide anything in a separate header
file the code is more readable without the macro.
This function creates a CoglBitmap which internally references a
CoglBuffer. The map and unmap functions will divert to mapping the
buffer. There are also now bind and unbind functions which should be
used instead of map and unmap whenever the data doesn't need to be
read from the CPU but will instead be passed to GL for packing or
unpacking. For bitmaps created from buffers this just binds the
bitmap.
cogl_texture_new_from_buffer now just uses this function to wrap the
buffer in a bitmap rather than trying to bind the buffer
immediately. This means that the buffer will be bound only at the
point right before the texture data is uploaded.
This approach means that using a pixel array will take the fastest
upload route if possible, but can still fallback to copying the data
by mapping the buffer if some conversion is needed. Previously it
would just crash in this case because the texture functions were all
passed a NULL pointer.
http://bugzilla.clutter-project.org/show_bug.cgi?id=2112
The CoglBitmap struct is now only defined within cogl-bitmap.c so that
all of its members can now only be accessed with accessor
functions. To get to the data pointer for the bitmap image you must
first call _cogl_bitmap_map and later call _cogl_bitmap_unmap. The map
function takes the same arguments as cogl_pixel_array_map so that
eventually we can make a bitmap optionally internally divert to a
pixel array.
There is a _cogl_bitmap_new_from_data function which constructs a new
bitmap object and takes ownership of the data pointer. The function
gets passed a destroy callback which gets called when the bitmap is
freed. This is similar to how gdk_pixbuf_new_from_data
works. Alternatively NULL can be passed for the destroy function which
means that the caller will manage the life of the pointer (but must
guarantee that it stays alive at least until the bitmap is
freed). This mechanism is used instead of the old approach of creating
a CoglBitmap struct on the stack and manually filling in the
members. It could also later be used to create a CoglBitmap that owns
a GdkPixbuf ref so that we don't necessarily have to copy the
GdkPixbuf data when converting to a bitmap.
There is also _cogl_bitmap_new_shared. This creates a bitmap using a
reference to another CoglBitmap for the data. This is a bit of a hack
but it is needed by the atlas texture backend which wants to divert
the set_region virtual to another texture but it needs to override the
format of the bitmap to ignore the premult flag.
There are many places in the texture backend that need to do
conversion using the CoglBitmap code. Currently none of these
functions can throw an error but they do return a value to indicate
failure. In future it would make sense if new texture functions could
throw an error and in that case they would want to use a CoglBitmap
error if the failure was due to the conversion. This moves the
internal CoglBitmap error from the quartz backend to be public in
cogl-bitmap.h so that it can be used in this way.
This replaces the use of CoglHandle with strongly type CoglBitmap *
pointers instead. The only function not converted for now is
cogl_is_bitmap which will be done in a later commit.
_cogl_bitmap_convert_format_and_premult was failing when converting
from RGBA to RGB and vice versa. _cogl_bitmap_fallback_convert
converts without altering the premult status so when choosing a new
format it would copy over the premult bit. However, it did this
regardless of whether the new format had an alpha channel so when
converting from RGBA_8888_PRE to RGB_888 it would end up inventing a
new meaningless format which would be RGB_888_PRE. This patch makes it
avoid copying the premult flag if the destination has no alpha. It
doesn't matter if it copies when the source format has no alpha
because it will always be unset.
_cogl_bitmap_convert_format_and_premult was also breaking when
converting from RGBA_8888_PRE to RGB_888 because it would think
RGB_888 is unpremultiplied and try to convert but then
_cogl_bitmap_fallback_premult wouldn't know how to do the conversion.
http://bugzilla.openedhand.com/show_bug.cgi?id=2057
Since using addresses that might change is something that finally
the FSF acknowledge as a plausible scenario (after changing address
twice), the license blurb in the source files should use the URI
for getting the license in case the library did not come with it.
Not that URIs cannot possibly change, but at least it's easier to
set up a redirection at the same place.
As a side note: this commit closes the oldes bug in Clutter's bug
report tool.
http://bugzilla.openedhand.com/show_bug.cgi?id=521
We've had complaints that our Cogl code/headers are a bit "special" so
this is a first pass at tidying things up by giving them some
consistency. These changes are all consistent with how new code in Cogl
is being written, but the style isn't consistently applied across all
code yet.
There are two parts to this patch; but since each one required a large
amount of effort to maintain tidy indenting it made sense to combine the
changes to reduce the time spent re indenting the same lines.
The first change is to use a consistent style for declaring function
prototypes in headers. Cogl headers now consistently use this style for
prototypes:
return_type
cogl_function_name (CoglType arg0,
CoglType arg1);
Not everyone likes this style, but it seems that most of the currently
active Cogl developers agree on it.
The second change is to constrain the use of redundant glib data types
in Cogl. Uses of gint, guint, gfloat, glong, gulong and gchar have all
been replaced with int, unsigned int, float, long, unsigned long and char
respectively. When talking about pixel data; use of guchar has been
replaced with guint8, otherwise unsigned char can be used.
The glib types that we continue to use for portability are gboolean,
gint{8,16,32,64}, guint{8,16,32,64} and gsize.
The general intention is that Cogl should look palatable to the widest
range of C programmers including those outside the Gnome community so
- especially for the public API - we want to minimize the number of
foreign looking typedefs.
The premult part of _cogl_convert_premult has now been split out as
_cogl_convert_premult_status. _cogl_convert_premult has been renamed
to _cogl_convert_format to make it less confusing. The premult
conversion is now done in-place instead of copying the
buffer. Previously it was copying the buffer once for the format
conversion and then copying it again for the premult conversion. The
premult conversion never changes the size of the buffer so it's quite
easy to do in place. We can also use the separated out function
independently.
As part of an incremental process to have Cogl be a standalone project we
want to re-consider how we organise the Cogl source code.
Currently this is the structure I'm aiming for:
cogl/
cogl/
<put common source here>
winsys/
cogl-glx.c
cogl-wgl.c
driver/
gl/
gles/
os/ ?
utils/
cogl-fixed
cogl-matrix-stack?
cogl-journal?
cogl-primitives?
pango/
The new winsys component is a starting point for migrating window system
code (i.e. x11,glx,wgl,osx,egl etc) from Clutter to Cogl.
The utils/ and pango/ directories aren't added by this commit, but they are
noted because I plan to add them soon.
Overview of the planned structure:
* The winsys/ API is the API that binds OpenGL to a specific window system,
be that X11 or win32 etc. Example are glx, wgl and egl. Much of the logic
under clutter/{glx,osx,win32 etc} should migrate here.
* Note there is also the idea of a winsys-base that may represent a window
system for which there are multiple winsys APIs. An example of this is
x11, since glx and egl may both be used with x11. (currently only Clutter
has the idea of a winsys-base)
* The driver/ represents a specific varient of OpenGL. Currently we have "gl"
representing OpenGL 1.4-2.1 (mostly fixed function) and "gles" representing
GLES 1.1 (fixed funciton) and 2.0 (fully shader based)
* Everything under cogl/ should fundamentally be supporting access to the
GPU. Essentially Cogl's most basic requirement is to provide a nice GPU
Graphics API and drawing a line between this and the utility functionality
we add to support Clutter should help keep this lean and maintainable.
* Code under utils/ as suggested builds on cogl/ adding more convenient
APIs or mechanism to optimize special cases. Broadly speaking you can
compare cogl/ to OpenGL and utils/ to GLU.
* clutter/pango will be moved to clutter/cogl/pango
How some of the internal configure.ac/pkg-config terminology has changed:
backendextra -> CLUTTER_WINSYS_BASE # e.g. "x11"
backendextralib -> CLUTTER_WINSYS_BASE_LIB # e.g. "x11/libclutter-x11.la"
clutterbackend -> {CLUTTER,COGL}_WINSYS # e.g. "glx"
CLUTTER_FLAVOUR -> {CLUTTER,COGL}_WINSYS
clutterbackendlib -> CLUTTER_WINSYS_LIB
CLUTTER_COGL -> COGL_DRIVER # e.g. "gl"
Note: The CLUTTER_FLAVOUR and CLUTTER_COGL defines are kept for apps
As the first thing to take advantage of the new winsys component in Cogl;
cogl_get_proc_address() has been moved from cogl/{gl,gles}/cogl.c into
cogl/common/cogl.c and this common implementation first trys
_cogl_winsys_get_proc_address() but if that fails then it falls back to
gmodule.
