Commit Graph

34 Commits

Author SHA1 Message Date
Robert Bragg
1d8fd64e1c meta-texture: This publicly exposes CoglMetaTexture
CoglMetaTexture is an interface for dealing with high level textures
that may be comprised of one or more low-level textures internally. The
interface allows the development of primitive drawing APIs that can draw
with high-level textures (such as atlas textures) even though the
GPU doesn't natively understand these texture types.

There is currently just one function that's part of this interface:
cogl_meta_texture_foreach_in_region() which allows an application to
resolve the internal, low-level textures of a high-level texture.
cogl_rectangle() uses this API for example so that it can easily emulate
the _REPEAT wrap mode for textures that the hardware can't natively
handle repeating of.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
2011-11-01 12:03:01 +00:00
Robert Bragg
4c3dadd35e Add a strong CoglTexture type to replace CoglHandle
As part of the on going, incremental effort to purge the non type safe
CoglHandle type from the Cogl API this patch tackles most of the
CoglHandle uses relating to textures.

We'd postponed making this change for quite a while because we wanted to
have a clearer understanding of how we wanted to evolve the texture APIs
towards Cogl 2.0 before exposing type safety here which would be
difficult to change later since it would imply breaking APIs.

The basic idea that we are steering towards now is that CoglTexture
can be considered to be the most primitive interface we have for any
object representing a texture. The texture interface would provide
roughly these methods:

  cogl_texture_get_width
  cogl_texture_get_height
  cogl_texture_can_repeat
  cogl_texture_can_mipmap
  cogl_texture_generate_mipmap;
  cogl_texture_get_format
  cogl_texture_set_region
  cogl_texture_get_region

Besides the texture interface we will then start to expose types
corresponding to specific texture types: CoglTexture2D,
CoglTexture3D, CoglTexture2DSliced, CoglSubTexture, CoglAtlasTexture and
CoglTexturePixmapX11.

We will then also expose an interface for the high-level texture types
we have (such as CoglTexture2DSlice, CoglSubTexture and
CoglAtlasTexture) called CoglMetaTexture. CoglMetaTexture is an
additional interface that lets you iterate a virtual region of a meta
texture and get mappings of primitive textures to sub-regions of that
virtual region. Internally we already have this kind of abstraction for
dealing with sliced texture, sub-textures and atlas textures in a
consistent way, so this will just make that abstraction public. The aim
here is to clarify that there is a difference between primitive textures
(CoglTexture2D/3D) and some of the other high-level textures, and also
enable developers to implement primitives that can support meta textures
since they can only be used with the cogl_rectangle API currently.

The thing that's not so clean-cut with this are the texture constructors
we have currently; such as cogl_texture_new_from_file which no longer
make sense when CoglTexture is considered to be an interface.  These
will basically just become convenient factory functions and it's just a
bit unusual that they are within the cogl_texture namespace.  It's worth
noting here that all the texture type APIs will also have their own type
specific constructors so these functions will only be used for the
convenience of being able to create a texture without really wanting to
know the details of what type of texture you need.  Longer term for 2.0
we may come up with replacement names for these factory functions or the
other thing we are considering is designing some asynchronous factory
functions instead since it's so often detrimental to application
performance to be blocked waiting for a texture to be uploaded to the
GPU.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
2011-09-21 15:27:03 +01:00
Neil Roberts
503f138fb6 texture: Call _cogl_texture_prepare_for_upload in set_region impl
Instead of calling _cogl_texutre_prepare_for_upload in
cogl_texture_set_region_from_bitmap the call is now deferred to the
implementation of the virtual for set_region. This is needed if the
texture backend is using a different format for the actual GL texture
than what is reported by cogl_texture_get_format. This happens for
example with atlas textures which report the original internal format
specified when the texture was created but actually always store the
data in an RGBA texture.

Also when creating an atlas texture from a bitmap it was preparing the
bitmap to be uploaded to the original format instead of the format of
the actual texture used for the atlas. Then it was using
cogl_texture_set_region_from_bitmap to upload the 5 pieces to make the
copies of the edge pixels. This would end up converting the image to
the actual format 5 times. The atlas textures have now been changed to
prepare the bitmap for the right format.

https://bugzilla.gnome.org/show_bug.cgi?id=657840

Reviewed-by: Robert Bragg <robert@linux.intel.com>
2011-09-05 19:02:04 +01:00
Robert Bragg
a9184d5cb7 Export API for uploading a tex subregion from a CoglBuffer
This exposes 2 experimental functions that make it possible to upload a
subregion of a texture from a CoglBuffer by first wrapping the buffer as
a CoglBitmap and then allowing uploading of a subregion from a
CoglBitmap. The new functions are:

cogl_bitmap_new_from_buffer() and
cogl_texture_set_region_from_bitmap()

Actually for now we are exporting this API for practical reasons since
we already had this API internally and it enables a specific feature
that was requested, but it is worth nothing that it's quite likely we
will replace these with functions that don't involve the CoglBitmap API
at some point.

For reference: The CoglBitmap API was actually removed from the 2.0
experimental API reference manual some time ago because the hope was
that we'd come up with a neater replacement. It doesn't seem entirely
clear what the scope of the CoglBitmap api is so it has became a bit of
a dumping ground.  CoglBitmap is used for image loading, as a means to
represent the layout of image data and also internally deals with format
conversions.

Note: Because we are avoiding including CoglBitmap as part of the 2.0
API these functions aren't currently included in the 2.0 reference
manual.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
2011-07-25 22:45:24 +01:00
Neil Roberts
5f181973a6 Move the cogl texture driver functions to a vtable
The texture driver functions are now accessed through a vtable pointed
to by a struct in the CoglContext so that eventually it will be
possible to compile both the GL and GLES texture drivers into a single
binary and then select between them at runtime.
2011-07-08 15:35:51 +01:00
Robert Bragg
1a5a4df326 journal: Support per-framebuffer journals
Instead of having a single journal per context, we now have a
CoglJournal object for each CoglFramebuffer. This means we now don't
have to flush the journal when switching/pushing/popping between
different framebuffers so for example a Clutter scene that involves some
ClutterEffect actors that transiently redirect to an FBO can still be
batched.

This also allows us to track state in the journal that relates to the
current frame of its associated framebuffer which we'll need for our
optimization for using the CPU to handle reading a single pixel back
from a framebuffer when we know the whole scene is currently comprised
of simple rectangles in a journal.
2011-01-21 16:18:10 +00:00
Neil Roberts
081eb2d75d cogl-texture: Remove the gl_handle from CoglTextureSliceCallback
There's no longer any need to use the GL handle in the callback for
_cogl_texture_foreach_sub_texture_in_region because it can now work in
terms of primitive cogl textures so it has now been removed. This
would be helpful if we ever want to make the foreach function public
so that apps could implement their own primitives using sliced
textures.
2010-11-11 16:25:13 +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
Neil Roberts
ccc3068ffd cogl-bitmap: Encapsulate the CoglBitmap even internally
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.
2010-07-15 17:24:01 +01:00
Neil Roberts
ae88bff329 Add a GL_GENERATE_MIPMAP fallback to the texture 2d and 3d backends
The CoglTexture2DSliced backend has a fallback for when the
framebuffer extension is missing so it's not possible to use
glGenerateMipmap. This involves keeping a copy of the upper-left pixel
of the tex image so that we can temporarily enable GL_GENERATE_MIPMAP
on the texture object and do a sub texture update by reuploading the
contents of the first pixel. This patch copies that mechanism to the
2D and 3D backends. The CoglTexturePixel structure which was
previously internal to the sliced backend has been moved to
cogl-texture-private.h so that it can be shared.
2010-07-13 18:41:01 +01:00
Neil Roberts
ec718d4ca4 Rename the third texure coordinate from 'r' to 'p'
Using 'r' to name the third component is problematic because that is
commonly used to represent the red component of a vector representing
a color. Under GLSL this is awkward because the texture swizzling for
a vector uses a single letter for each component and the names for
colors, textures and positions are synonymous. GLSL works around this
by naming the components of the texture s, t, p and q. Cogl already
effectively already exposes this naming because it exposes GLSL so it
makes sense to use that naming consistently. Another alternative could
be u, v and w. This is what Blender and Direct3D use. However the w
component conflicts with the w component of a position vertex.
2010-07-13 14:29:07 +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
Neil Roberts
61cbeeacfa cogl-texture: Share the common code in the set_region virtual
There was a lot of common code that was copied to all of the backends
to convert the data to a suitable format and wrap it into a CoglBitmap
so that it can be passed to _cogl_texture_driver_upload_subregion_to_gl.
This patch moves the common code to cogl-texture.c so that the virtual
just takes a CoglBitmap that is already in the right format.
2010-07-09 11:14:14 +01:00
Neil Roberts
223317c500 cogl-texture: Share the common code in the get_data virtual
Previously cogl_texture_get_data would pretty much directly pass on to
the get_data texture virtual function. This ended up with a lot of
common code that was copied to all of the backends. For example, the
method is expected to return the required data size if the data
pointer is NULL and to calculate its own rowstride if the rowstride is
0. Also it needs to convert the downloaded data if GL can't support
that format directly.

This patch moves the common code to cogl-texture.c so the virtual is
always called with a format that can be downloaded directly by GL and
with a valid rowstride. If the download fails then the virtual can
return FALSE in which case cogl-texture will use the draw and read
fallback.
2010-07-09 11:00:48 +01:00
Neil Roberts
82e63a4753 cogl-texture: Replace the ensure_mipmaps virtual with pre_paint
Instead of the ensure_mipmaps virtual that is only called whenever the
texture is about to be rendered with a min filter that needs the
mipmap, there is now a pre_paint virtual that is always called when
the texture is about to be painted in any way. It has a flags
parameter which is used to specify whether the mipmap will be needed.

This is useful for CoglTexturePixmapX11 because it needs to do stuff
before painting that is unrelated to mipmapping.
2010-06-22 11:47:33 +01:00
Neil Roberts
ebb05bcb64 cogl-texture: List texture subclass types rather than hardcoding them
Instead of having a hardcoded series of if-statements in
cogl_is_texture to determine which types should appear as texture
subclasses, they are now stored in a GSList attached to the Cogl
context. The list is amended to using a new cogl_texture_register_type
function. There is a convenience macro called COGL_TEXTURE_DEFINE
which uses COGL_HANDLE_DEFINE_WITH_CODE to register the texture type
when the _get_type() function is first called.
2010-06-22 11:47:33 +01:00
Robert Bragg
82e80e6765 material: Avoid redundant glBindTexture calls
This adds a _cogl_bind_gl_texture_transient function that should be used
instead of glBindTexture so we can have a consistent cache of the
textures bound to each texture unit so we can avoid some redundant
binding.
2010-06-09 17:26:15 +01:00
Neil Roberts
fb7f1a7fd6 Split the wrap mode of _cogl_texture_set_wrap_mode into three
GL supports setting different wrap modes for the s, t and r
coordinates so we should design the backend interface to support that
also. The r coordinate is not currently used by any of the backends
but we might as well have it to make life easier if we ever add
support for 3D textures.

http://bugzilla.openedhand.com/show_bug.cgi?id=2063
2010-04-12 15:44:23 +01:00
Owen W. Taylor
770ca1311d Fix checks for out-of-bounds coordinates and repeats
Add a return result from CoglTexture.transform_quad_coords_to_gl(),
so that we can properly determine the nature of repeats in
the face of GL_TEXTURE_RECTANGLE_ARB, where the returned
coordinates are not normalized.

The comment "We also work out whether any of the texture
coordinates are outside the range [0.0,1.0]. We need to do
this after calling transform_coords_to_gl in case the texture
backend is munging the coordinates (such as in the sub texture
backend)." is disregarded and removed, since it's actually
the virtual coordinates that determine whether we repeat,
not the GL coordinates.

Warnings about disregarded layers are used in all cases where
applicable, including for subtextures.

http://bugzilla.openedhand.com/show_bug.cgi?id=2016

Signed-off-by: Neil Roberts <neil@linux.intel.com>
2010-03-15 16:09:41 +00:00
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
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
Neil Roberts
e83e0c3e5b cogl-texture: Split out _cogl_texture_prepare_for_upload
The Cogl atlas code was using _cogl_texture_prepare_for_upload with a
NULL pointer for the dst_bmp to determine the internal format of the
texture without converting the bitmap. It needs to do this to decide
whether the texture will go in the atlas before wasting time on the
conversion. This use of the function is a little confusing so that
part of it has been split out into a new function called
_cogl_texture_determine_internal_format. The code to decide whether a
premult conversion is needed has also been split out.
2010-02-03 23:10:52 +00:00
Neil Roberts
e20c98e548 cogl: Let GL do the format conversion when uploading texture data
Cogl accepts a pixel format for both the data in memory and the
internal format to be used for the texture. If they do not match then
it would convert them using the CoglBitmap functions before uploading
the data. However, GL also lets you specify both formats so it makes
more sense to let GL do the conversion. The driver may need the
texture in a specific format so it may end up being converted anyway.

The cogl_texture_upload_data functions have been removed and replaced
with a single function to prepare the bitmap. This will only do the
premultiplication conversion because that is the only part that GL
can't do directly.
2010-02-01 13:27:34 +00:00
Neil Roberts
ae7825275e cogl: Make CoglSubTexture only work for quad rendering
The sub texture backend doesn't work well as a completely general
texture backend because for example when rendering with cogl_polygon
it needs to be able to tranform arbitrary texture coordinates without
reference to the other coordintes. This can't be done when the texture
coordinates are a multiple of one because sometimes the coordinate
should represent the left or top edge and sometimes it should
represent the bottom or top edge. For example if the s coordinates are
0 and 1 then 1 represents the right edge but if they are 1 and 2 then
1 represents the left edge.

Instead the sub-textures are now documented not to support coordinates
outside the range [0,1]. The coordinates for the sub-region are now
represented as integers as this helps avoid rounding issues. The
region can no longer be a super-region of the texture as this
simplifies the code quite a lot.

There are two new texture virtual functions:

transform_quad_coords_to_gl - This transforms two pairs of coordinates
     representing a quad. It will return FALSE if the coordinates can
     not be transformed. The sub texture backend uses this to detect
     coordinates that require repeating which causes cogl-primitives
     to use manual repeating.

ensure_non_quad_rendering - This is used in cogl_polygon and
     cogl_vertex_buffer to inform the texture backend that
     transform_quad_to_gl is going to be used. The atlas backend
     migrates the texture out of the atlas when it hits this.
2010-01-18 09:22:04 +00:00
Neil Roberts
05d42ed390 cogl: Add a CoglTexture2D backend
This is an optimised version of CoglTexture2DSliced that always deals
with a single texture and always uses the GL_TEXTURE_2D
target. cogl_texture_new_from_bitmap now tries to use this backend
first. If it can't create a texture with that size then it falls back
the sliced backend.

cogl_texture_upload_data_prepare has been split into two functions
because the sliced backend needs to know the real internal format
before the conversion is performed. Otherwise the converted bitmap
will be wasted if the backend can't support the size.
2009-12-02 22:03:27 +00:00
Neil Roberts
7c5aea9b68 cogl: Make the callback for foreach_sub_texture_in_region use const
The CoglTextureSliceCallback function pointer now takes const pointers
for the texture coordinates. This makes it clearer that the callback
should not modify the array and therefore the backend can use the same
array for both sets of coords.
2009-12-02 22:03:08 +00:00
Neil Roberts
6bc3319c86 cogl: Add a texture utility function for manually repeating
Given a region of texture coordinates this utility invokes a callback
enough times to cover the region with a subregion that spans the
texture at most once. Eg, if called with tx1 and tx2 as 0.5 and 3.0 it
it would invoke the callback with:

0.5,1.0  1.0,2.0  2.0,3.0

Manual repeating is needed by all texture backends regardless of
whether they can support hardware repeating because when Cogl calls
the foreach_sub_texture_in_region method then it sets the wrap mode to
GL_CLAMP_TO_EDGE and no hardware repeating is possible.
2009-12-02 22:03:08 +00:00
Neil Roberts
25f3b993c6 cogl: Move all of the fields from CoglTexture to CoglTexture2DSliced
Most of the fields that were previously in CoglTexture are specific to
the implementation of CoglTexture2DSliced so they should be placed
there instead. For example, the 'mipmaps_dirty' flag is an
implementation detail of the ensure_mipmaps function so it doesn't
make sense to force all texture backends to have this function.

Other fields such as width, height, gl_format and format may make
sense for all textures but I've added them as virtual functions
instead. This may make more sense for a sub-texture backend for
example where it can calculate these based on the full texture.
2009-12-02 22:03:07 +00:00
Neil Roberts
5030356e0e cogl: Move data only used for upload out of CoglTexture
The CoglTexture struct previously contained some fields which are only
used to upload data such as the CoglBitmap and the source GL
format. These are now moved to a separate CoglTextureUploadData struct
which only exists for the duration of one of the cogl_texture_*_new
functions. In cogl-texture there are utility functions which operate
on this new struct rather than on CoglTexture directly.

Some of the fields that were previously stored in the CoglBitmap
struct are now copied to the CoglTexture such as the width, height,
format and internal GL format.

The rowstride was previously stored in CoglTexture and this was
publicly accessible with the cogl_texture_get_rowstride
function. However this doesn't seem to be a useful function because
there is no need to use the same rowstride again when uploading or
downloading new data. Instead cogl_texture_get_rowstride now just
calculates a suitable rowstride from the format and width of the
texture.
2009-12-02 22:03:07 +00:00
Neil Roberts
1df0e36c6c cogl: Use a vtable for the texture backends instead of a type and switch
Instead of storing an enum with the backend type for each texture and
then using a switch statement to decide which function to call, we
should store pointers to all of the functions in a struct and have
each texture point to that struct. This is potentially slightly faster
when there are more backends and it makes implementing new backends
easier because it's more obvious which functions have to be
implemented.
2009-11-25 13:47:28 +00:00
Robert Bragg
861766f4ad [cogl-primitives] Split the journal out from cogl-primitives.c
The Journal can be considered a standalone component, so even though
it's currently only used to log quads, it seems better to split it
out into its own file.
2009-10-16 18:58:52 +01:00
Vladimir Nadvornik
65015a137e [cogl-texture] Split CoglTexture into an abstract class + CoglTexture2dSliced
cogl-texture-2d-sliced provides an implementation of CoglTexture and this
seperation lays the foundation for potentially supporting atlas textures,
pixmap textures (as in GLX_EXT_texture_from_pixmap) and fast-path
GL_TEXTURE_{1D,2D,3D,RECTANGLE} textures in a maintainable fashion.
2009-10-16 18:58:51 +01:00
Robert Bragg
c40d5ae9ea [cogl-texture] Seal CoglTexture internals from cogl-primitives.c
cogl-primitives.c was previously digging right into CoglTextures so it could
manually iterate the texture slices for texturing quads and polygons and
because we were missing some state getters we were lazily just poking into
the structures directly.

This adds some extra state getter functions, and adds a higher level
_cogl_texture_foreach_slice () API that hopefully simplifies the way in
which sliced textures may be used to render primitives.  This lets you
specify a rectangle in "virtual" texture coords and it will call a given
callback for each slice that intersects that rectangle giving the virtual
coords of the current slice and corresponding "real" texture coordinates for
the underlying gl texture.

At the same time a noteable bug in how we previously iterated sliced
textures was fixed, whereby we weren't correctly handling inverted texture
coordinates.  E.g.  with the previous code if you supplied texture coords of
tx1=100,ty1=0,tx2=0,ty2=100 (inverted along y axis) that would result in a
back-facing quad, which could be discarded if using back-face culling.
2009-10-16 18:58:51 +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