Commit Graph

42 Commits

Author SHA1 Message Date
Neil Roberts
2b812d3d04 cogl-clip-stack: Fix flushing multiple stencil rectangles
When flushing a clip stack that contains more than one rectangle which
needs to use the stencil buffer the code takes a different path so
that it can combine the new rectangle with the existing contents of
the stencil buffer. However it was not correctly flushing the
modelview and projection matrices so that rectangle would be in the
wrong place.
2011-01-24 17:40:07 +00:00
Neil Roberts
2ddab50ae4 cogl-debug: Add a debug option for tracing clipping
This adds a COGL_DEBUG=clipping option that reports how the clip is
being flushed. This is needed to determine whether the scissor,
stencil clip planes or software clipping is being used.
2011-01-24 17:39:48 +00:00
Robert Bragg
cf92670fbb clip-stack: Adds _cogl_clip_stack_get_bounds API
This adds an internal function to be able to query the screen space
bounding box of the current clip entries contained in a given
CoglClipStack.

This bounding box which is cheap to determine can be useful to know the
largest extents that might be updated while drawing with this clip
stack.

For example the plan is to use this as part of an optimized read-pixel
path handled on the CPU which will need to track the currently valid
extents of the last call to cogl_clear()
2011-01-21 16:18:10 +00:00
Neil Roberts
dc1f1949d0 Remove the GLES2 wrapper
The GLES2 wrapper is no longer needed because the shader generation is
done within the GLSL fragend and vertend and any functions that are
different for GLES2 are now guarded by #ifdefs.
2010-12-13 17:29:14 +00:00
Neil Roberts
7294e5552c cogl-clip-stack: Move the struct definitions to the header
It will be useful to be able to directly examine the contents of the
clip stack within the journal code.
2010-12-03 17:16:58 +00:00
Neil Roberts
07e49d5257 cogl-clip-stack: Don't convert rect clips to window clips
Previously in cogl-clip-state.c when it detected that the current
modelview matrix is screen-aligned it would convert the clip entry to
a window clip. Instead of doing this cogl-clip-stack.c now contains
the detection and keeps the entry as a rectangle clip but marks that
it is entirely described by its scissor rect. When flusing the clip
stack it doesn't do anything extra for entries that have this mark
(because the clip will already been setup by the scissor). This is
needed so that we can still track the original rectangle coordinates
and modelview matrix to help detect when it would be faster to modify
the rectangle when adding it to the journal rather than having to
break up the batch to set the clip state.
2010-12-03 17:16:57 +00:00
Robert Bragg
0ec9e406ea clip-stack: combine modelview-projection in set_clip_planes
When using clip planes and we we have to project some vertices into
screen coordinates we used to transform those by the modelview and then
the projection matrix separately. Now we combine the modelview and
projection matrix and then use that to transform the vertices in one
step instead.
2010-11-23 12:50:29 +00:00
Neil Roberts
caa991d7a1 cogl: Don't flush the journal when flushing clip state
Flushing the clip state no longer does anything that would cause the
journal to flush. The clip state is only flushed when flushing the
framebuffer state and in all cases this ends up flushing the journal
in one way or another anyway. Avoiding flushing the journal will make
it easier to log the clip state in the journal.

Previously when trying to set up a rectangle clip that can't be
scissored or when using a path clip the code would use cogl_rectangle
as part of the process to fill the stencil buffer. This is now changed
to use a new internal _cogl_rectangle_immediate function which
directly uses the vertex array API to draw a triangle strip without
affecting the journal. This should be just as efficient as the
previous journalled code because these places would end up flushing
the journal immediately before and after submitting the single
rectangle anyway and flushing the journal always creates a new vbo so
it would effectively do the same thing.

Similarly there is also a new internal _cogl_clear function that does
not flush the journal.
2010-11-04 18:10:08 +00:00
Neil Roberts
0c8eb904c0 cogl: Move the clip stack dirtiness to the context rather than the FB
Previously we tracked whether the clip stack needs flushing as part of
the CoglClipState which is part of the CoglFramebuffer state. This is
a bit odd because most of the clipping state (such as the clip planes
and the scissor) are part of the GL context's state rather than the
framebuffer. We were marking the clip state on the framebuffer dirty
every time we change the framebuffer anyway so it seems to make more
sense to have the dirtiness be part of the global context.

Instead of a just a single boolean to record whether the state needs
flushing, the CoglContext now holds a reference to the clip stack that
was flushed. That way we can flush arbitrary stack states and if it
happens to be the same as the state already flushed then Cogl will do
nothing. This will be useful if we log the clip stack in the journal
because then we will need to flush unrelated clip stack states for
each batch.
2010-11-04 18:08:27 +00:00
Neil Roberts
f15b47cc03 cogl-clip-stack: Don't allocate a separate struct for CoglClipStack
Instead of having a separate CoglHandle for CoglClipStack the code is
now expected to directly hold a pointer to the top entry on the
stack. The empty stack is then the NULL pointer. This saves an
allocation when we want to copy the stack because we can just take a
reference on a stack entry. The idea is that this will make it
possible to store the clip stack in the journal without any extra
allocations.

The _cogl_get_clip_stack and set functions now take a CoglClipStack
pointer instead of a handle so it would no longer make sense to make
them public. However I think the only reason we would have wanted that
in the first place would be to save the clip state between switching
FBOs and that is no longer necessary.
2010-11-04 18:08:27 +00:00
Robert Bragg
f80cb197a9 cogl: rename CoglMaterial -> CoglPipeline
This applies an API naming change that's been deliberated over for a
while now which is to rename CoglMaterial to CoglPipeline.

For now the new pipeline API is marked as experimental and public
headers continue to talk about materials not pipelines. The CoglMaterial
API is now maintained in terms of the cogl_pipeline API internally.
Currently this API is targeting Cogl 2.0 so we will have time to
integrate it properly with other upcoming Cogl 2.0 work.

The basic reasons for the rename are:
- That the term "material" implies to many people that they are
  constrained to fragment processing; perhaps as some kind of high-level
  texture abstraction.
    - In Clutter they get exposed by ClutterTexture actors which may be
      re-inforcing this misconception.
- When comparing how other frameworks use the term material, a material
  sometimes describes a multi-pass fragment processing technique which
  isn't the case in Cogl.
- In code, "CoglPipeline" will hopefully be a much more self documenting
  summary of what these objects represent; a full GPU pipeline
  configuration including, for example, vertex processing, fragment
  processing and blending.
- When considering the API documentation story, at some point we need a
  document introducing developers to how the "GPU pipeline" works so it
  should become intuitive that CoglPipeline maps back to that
  description of the GPU pipeline.
- This is consistent in terminology and concept to OpenGL 4's new
  pipeline object which is a container for program objects.

Note: The cogl-material.[ch] files have been renamed to
cogl-material-compat.[ch] because otherwise git doesn't seem to treat
the change as a moving the old cogl-material.c->cogl-pipeline.c and so
we loose all our git-blame history.
2010-11-03 18:09:23 +00:00
Robert Bragg
1b9a247174 cogl: Adds {push,pop,get}_source functions
This exposes the idea of a stack of source materials instead of just
having a single current material. This allows the writing of orthogonal
code that can change the current source material and restore it to its
previous state. It also allows the implementation of new composite
primitives that may want to validate the current source material and
possibly make override changes in a derived material.
2010-10-26 12:08:20 +01:00
Neil Roberts
2c8bf00995 Don't define public cogl_is_* functions for internal types
This adds a COGL_OBJECT_INTERNAL_DEFINE macro and friends that are the
same as COGL_OBJECT_DEFINE except that they prefix the cogl_is_*
function with an underscore so that it doesn't get exported in the
shared library.
2010-07-09 18:57:54 +01:00
Robert Bragg
0e43647fed gles2: don't disable clip planes for GLES2
GLES2 doesn't provide user clip planes (you would have to use a vertex +
fragment shader to achieve the same kind of result) so we make sure not
to call glEnable/Disable with any of the GL_CLIP_PLANE0..3 defines.

http://bugzilla.o-hand.com/show_bug.cgi?id=2177
2010-06-22 11:35:22 +01:00
Neil Roberts
0bbf50f905 cogl-clip-stack: Always use the scissor when clipping
Whenever a path or a rectangle is added to the clip stack it now also
stores a screen space bounding box in the entry. Then when the clip
stack is flushed the bounding box is first used to set up the
scissor. That way when we eventually come to use the stencil buffer
the clear will be affected by the scissor so we don't have to clear
the entire buffer.
2010-06-10 21:52:55 +01:00
Robert Bragg
595271ac87 clip_stack: Remove use of CoglHandle in the CoglClipStack API
This replaces the use of CoglHandle with strongly type CoglClipStack *
pointers instead. The only function not converted for now is
cogl_is_clip_stack which will be done in a later commit.
2010-06-01 12:20:59 +01:00
Damien Lespiau
45a947d226 analysis: Use static functions when possible
It's best to ensure the functions only used in one compilation unit are
marked as static so GCC can inline them if it feels like it.
2010-06-01 12:08:18 +01:00
Neil Roberts
11532f79ec cogl-clip-stack: Set *stencil_used_p when the stack is empty
If the clip stack is empty then _cogl_clip_stack_flush exits
immediately. This was missing out the assignment of *stencil_used_p at
the bottom of the function. If a path is then used after the clip is
cleared then it would think it needs to merge with the clip so the
stencil would not be cleared correctly.
2010-05-06 14:15:04 +01:00
Neil Roberts
9d93e250d1 cogl-clip-stack: Use orientation of the polygon to set clip planes
Previously the clip stack code was trying to detect when the
orientation of the on-screen rectangle had changed by checking if the
order of the y-coordinates on the left edge was different from the
order the x-coordinates on the top edge. This doesn't work for some
rotations which was causing the clip planes to clip the wrong side of
the line. This patch makes it detect the orientation by calculating
the signed area which is a standard computer graphics algorithm.

http://bugzilla.openedhand.com/show_bug.cgi?id=2079
2010-04-21 13:24:59 +01:00
Neil Roberts
30c4678ff4 cogl: Implement retained clip stacks
This adds three new internal API functions which can be used to retain
the clip stack state and restore it later:

 _cogl_get_clip_stack
 _cogl_set_clip_stack
 _cogl_clip_stack_copy

The functions are currently internal and not yet used but we may want
to make them public in future to replace the cogl_clip_stack_save()
and cogl_clip_stack_restore() APIs.

The get function just returns the handle to the clip stack at the top
of the stack of stacks and the set function just replaces it.

The copy function makes a cheap copy of an existing stack by taking a
reference to the top stack entry. This ends up working like a deep
copy because there is no way to modify entries of a stack but it
doesn't actually copy the data.
2010-04-15 14:51:01 +01:00
Neil Roberts
84b87e811e cogl-clip-stack: Convert to be a CoglHandle
CoglClipStacks can now be reference counted via a CoglHandle. The
ClipClipState now stores handles in the list rather than CoglClipStack
pointers.
2010-04-15 14:51:01 +01:00
Neil Roberts
f6f375cb36 Separate out CoglClipStackState from cogl-clip-stack.c
CoglClipStackState has now been renamed to CoglClipState and is moved
to a separate file. CoglClipStack now just maintains a stack and
doesn't worry about the rest of the state. CoglClipStack sill contains
the code to flush the stack to GL.
2010-04-15 14:51:00 +01:00
Neil Roberts
07a76aacfb cogl-slip-stack: Store clip window rect entries in Cogl coordinates
When glScissor is called it needs to pass coordinates in GL's
coordinate space where the origin is the bottom left. Previously this
conversion was done before storing the window rect in the clip
stack. However this might make it more difficult if we want to be able
to grab a handle to a clip stack and use it in different circumstances
later. This patch moves the coordinate conversion to inside the clip
state flushing code.
2010-04-15 14:50:55 +01:00
Neil Roberts
2f63146474 cogl-clip-stack: Store window rect entries as ints not floats
The window rectangles are passed in as integers so there is no point
in converting them to floats when storing a stack entry for them.
2010-04-15 14:50:26 +01:00
Neil Roberts
71fdc54dde cogl-clip-stack: Use reference counted stack entries
The stack is now stored as a list of reference counted entries.
Instead of using a GList, each entry now contains a link with a
reference to its parent. The idea is that this would allow copying
stacks with a shared ancestry.

Previously the code flushed the state by finding the bottom of the
stack and then applying each entry by walking back up to the top. This
is slightly harder to do now because the list is no longer
doubly-linked. However I don't think it matters which order the
entries are applied so I've just changed it to apply them in reverse
order.

There was also a restriction that if ever the stencil buffer is used
then we could no longer use clip planes for any subsequent entries. I
don't think this makes sense because it should always work as long as
it doesn't attempt to use the clip planes more than once. I've
therefore removed the restriction.
2010-04-15 14:47:01 +01:00
Neil Roberts
067a520f26 cogl: Support retained paths
This adds three new API calls:

  CoglHandle cogl_path_get()
  void cogl_path_set(CoglHandle path)
  CoglHandle cogl_path_copy(CoglHandle path)

All of the fields relating to the path have been moved from the Cogl
context to a new CoglPath handle type. The cogl context now just
contains a CoglPath handle. All of the existing path commands
manipulate the data in the current path handle. cogl_path_new now just
creates a new path handle and unrefs the old one.

The path handle can be stored for later with cogl_path_get. The path
can then be copied with cogl_path_copy. Internally it implements
copy-on-write semantics with an extra optimisation that it will only
copy the data if the new path is modified, but not if the original
path is modified. It can do this because the only way to modify a path
is by appending to it so the copied path is able to store its own path
length and only render the nodes up to that length. For this to work
the copied path also needs to keep its own copies of the path extents
because the parent path may change these by adding nodes.

The clip stack now uses the cogl_path_copy mechanism to store paths in
the stack instead of directly copying the data. This should save some
memory and processing time.
2010-04-08 19:53:38 +01:00
Emmanuele Bassi
72f4ddf532 Remove mentions of the FSF address
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
2010-03-01 12:56:10 +00:00
Neil Roberts
1d54ecb8a1 cogl-clip-stack: Round the coords when clipping to a window rect
The size and position of the window rectangle for clipping in
try_pushing_rect_as_window_rect is calculated by projecting the
rectangle coordinates. Due to rounding errors, this can end up with
slightly off numbers like 34.999999. These were then being cast
directly to an integer so it could end up off by one.

This uses a new macro called COGL_UTIL_NEARBYINT which is a
replacement for the C99 nearbyint function.
2010-02-17 16:12:47 +00:00
Robert Bragg
ba4b00be42 cogl: remove redundant _cogl_journal_flush prototype
There was a redundant _cogl_journal_flush function prototype in
cogl-primitives.h
2010-02-12 14:05:01 +00:00
Robert Bragg
0f5f4e8645 cogl: improves header and coding style consistency
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.
2010-02-12 14:05:00 +00:00
Robert Bragg
944423a8d9 cogl: deprecate cogl_draw_buffer API and replace with a cogl_framebuffer API
cogl_push_draw_buffer, cogl_set_draw_buffer and cogl_pop_draw_buffer are now
deprecated and new code should use the new cogl_framebuffer_* API instead.

Code that previously did:
    cogl_push_draw_buffer ();
    cogl_set_draw_buffer (COGL_OFFSCREEN_BUFFER, buffer);
    /* draw */
    cogl_pop_draw_buffer ();
should now be re-written as:
    cogl_push_framebuffer (buffer);
    /* draw */
    cogl_pop_framebuffer ();

As can be seen from the example above the rename has been used as an
opportunity to remove the redundant target argument from
cogl_set_draw_buffer; it now only takes one call to redirect to an offscreen
buffer, and finally the term framebuffer may be a bit more familiar to
anyone coming from an OpenGL background.
2009-11-26 19:33:14 +00:00
Neil Roberts
d309272901 [cogl-primitives] Don't clear the whole stencil buffer
When _cogl_add_path_to_stencil_buffer is used to draw a path we don't
need to clear the entire stencil buffer. Instead it can clear just the
bounding box of the path. This adds an extra parameter called
'need_clear' which is only set if the stencil buffer is being used for
clipping.

http://bugzilla.openedhand.com/show_bug.cgi?id=1829
2009-11-13 10:51:47 +00:00
Robert Bragg
b0c60ce77a [clip-stack] stop using deprecated cogl_clip_push_window_rect API
try_pushing_rect_as_window_rect now uses the new
cogl_clip_push_window_rectangle API.
2009-11-05 21:10:17 +00:00
Robert Bragg
2e0e441031 [cogl-clip] deprecate parts and cleanup the API
cogl_clip_push() which accepts a rectangle in model space shouldn't have
been defined to take x,y,width,height arguments because this isn't consistant
with other Cogl API dealing with model space rectangles.  If you are using a
coordinate system with the origin at the center and the y+ extending up,
then x,y,width,height isn't as natural as (x0,y0)(x1,y1). This API has
now been replace with cogl_clip_push_rectangle()

(As a general note: the Cogl API should only use the x,y,width,height style
when the appropriate coordinate space is defined by Cogl to have a top left
origin.  E.g.  window coordinates, or potentially texture coordinates)

cogl_clip_push_window_rect() shouldn't have been defined to take float
arguments since we only clip with integral pixel precision. We also
shouldn't have abbreviated "rectangle". This API has been replaced with
cogl_clip_push_window_rectangle()

cogl_clip_ensure() wasn't documented at all in Clutter 1.0 and probably
no one even knew it existed. This API isn't useful, and so it's now
deprecated. If no one complains we may remove the API altogether for
Clutter 1.2.

cogl_clip_stack_save() and cogl_clip_stack_restore() were originally added
to allow us to save/restore the clip when switching to/from offscreen
rendering.  Now that offscreen draw buffers are defined to own their clip
state and the state will be automatically saved and restored this API is now
redundant and so deprecated.
2009-11-05 21:10:17 +00:00
Robert Bragg
1af8be2f70 [clip-stack] Internally track model space clip rects as (x0,y0)(x1,y1) pairs
Don't track the rectangles as x0,y0,width,height. This is in preparation
for some API tidy up.
2009-11-05 21:10:17 +00:00
Robert Bragg
6ca49145f4 [clip-stack] move lots of supporting code from cogl.c to cogl-clip-stack.c
There was quite a bit of code in cogl.c that was only used to support
cogl-clip-stack.c, so this has now been moved to cogl-clip-stack.c
2009-11-05 21:10:16 +00:00
Robert Bragg
57bd250a71 [cogl_clip_push_window_rect] fix Cogl -> GL coordinate conversion
Firstly this now uses the draw buffer height not the viewport height
when we need to perform a y = height - y conversion, since (as the
name suggests) we are dealing with window coordinates not viewport
coordinates.

Secondly this skips any conversion when the current draw buffer is an
offscreen draw buffer since offscreen rendering is always forced to be
upside down and in this case Cogl window coordinates == GL window
coordinates.
2009-11-04 03:34:05 +00:00
Robert Bragg
0f86470eef [clip-stack] tidy up transform_point() code
I was originally expecting the code not to handle offset viewports or
viewports with a different size to the framebuffer, but it turns out the
code worked fine.  In the process though I think I made the code slightly
more readable.
2009-11-04 03:32:52 +00:00
Robert Bragg
49db9f4f77 [clip-stack] Handle flipped rectangles in try_pushing_rect_as_window_rect()
We were ignoring the possibility that the current modelview matrix may flip
the incoming rectangle in which case we didn't calculate a valid scissor
rectangle for clipping.

This fixes: http://bugzilla.o-hand.com/show_bug.cgi?id=1809
(Clipping doesn't work within an FBO)
2009-11-04 03:23:19 +00:00
Robert Bragg
bb3a008318 [draw-buffers] First pass at overhauling Cogl's framebuffer management
Cogl's support for offscreen rendering was originally written just to support
the clutter_texture_new_from_actor API and due to lack of documentation and
several confusing - non orthogonal - side effects of using the API it wasn't
really possible to use directly.

This commit does a number of things:
- It removes {gl,gles}/cogl-fbo.{c,h} and adds shared cogl-draw-buffer.{c,h}
  files instead which should be easier to maintain.
- internally CoglFbo objects are now called CoglDrawBuffers. A
  CoglDrawBuffer is an abstract base class that is inherited from to
  implement CoglOnscreen and CoglOffscreen draw buffers.  CoglOffscreen draw
  buffers will initially be used to support the
  cogl_offscreen_new_to_texture API, and CoglOnscreen draw buffers will
  start to be used internally to represent windows as we aim to migrate some
  of Clutter's backend code to Cogl.
- It makes draw buffer objects the owners of the following state:
  - viewport
  - projection matrix stack
  - modelview matrix stack
  - clip state
(This means when you switch between draw buffers you will automatically be
 switching to their associated viewport, matrix and clip state)

Aside from hopefully making cogl_offscreen_new_to_texture be more useful
short term by having simpler and well defined semantics for
cogl_set_draw_buffer, as mentioned above this is the first step for a couple
of other things:
- Its a step toward moving ownership for windows down from Clutter backends
  into Cogl, by (internally at least) introducing the CoglOnscreen draw
  buffer.  Note: the plan is that cogl_set_draw_buffer will accept on or
  offscreen draw buffer handles, and the "target" argument will become
  redundant since we will instead query the type of the given draw buffer
  handle.
- Because we have a common type for on and offscreen framebuffers we can
  provide a unified API for framebuffer management. Things like:
  - blitting between buffers
  - managing ancillary buffers (e.g. attaching depth and stencil buffers)
  - size requisition
  - clearing
2009-11-03 17:23:03 +00:00
Robert Bragg
eed2479556 [cogl] Removes the cogl-current-matrix abstraction
The indirection through this API isn't necessary since we no longer
arbitrate between the OpenGL matrix API and Cogl's client side API.  Also it
doesn't help to maintain an OpenGL style matrix mode API for internal use
since it's awkward to keep restoring the MODELVIEW mode and easy enough to
directly work with the matrix stacks of interest.

This replaces use of the _cogl_current_matrix API with direct use of the
_cogl_matrix_stack API.  All the unused cogl_current_matrix API is removed
and the matrix utility code left in cogl-current-matrix.c was moved to
cogl.c.
2009-10-20 12:32:50 +01:00
Robert Bragg
0bce7eac53 Intial Re-layout of the Cogl source code and introduction of a Cogl Winsys
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.
2009-10-16 18:58:50 +01:00