Instead of using GL_TRIANGLES and uploading the indices every time, it
now uses GL_QUADS instead on OpenGL. Under GLES it still uses indices
but it uses the new cogl_vertex_buffer_indices_get_for_quads function
to avoid uploading the vertices every time.
This requires the _cogl_vertex_buffer_indices_pointer_from_handle
function to be exposed privately to the rest of Cogl.
The static_indices array has been removed from the Cogl context.
Previously indices were tightly bound to a particular Cogl vertex buffer
but we would like to be able to share indices so now we have
cogl_vertex_buffer_indices_new () which returns a CoglHandle.
In particular we could like to have a shared set of indices for drawing
lists of quads that can be shared between the pango renderer and the
Cogl journal.
It's now possible to add arrays of indices to a Cogl vertex buffer and
they will be put into an OpenGL vertex buffer object. Since it's quite
common for index arrays to be static it saves the OpenGL driver from
having to validate them repeatedly.
This changes the cogl_vertex_buffer_draw_elements API: It's no longer
possible to provide a pointer to an index array at draw time. So
cogl_vertex_buffer_draw_elements now takes an indices identifier that
should correspond to an idendifier returned when calling
cogl_vertex_buffer_add_indices ()
Adds missing notices, and ensures all the notices are consistent. The Cogl
blurb also now reads:
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
Buffer objects aren't currently available for glx indirect contexts, so we
now have a fallback that simply allocates fake client side vbos to store the
attributes.
The cogl_is_* functions were showing up quite high on profiles due to
iterating through arrays of cogl handles.
This does away with all the handle arrays and implements a simple struct
inheritance scheme. All cogl objects now add a CoglHandleObject _parent;
member to their main structures. The base object includes 2 members a.t.m; a
ref_count, and a klass pointer. The klass in turn gives you a type and
virtual function for freeing objects of that type.
Each handle type has a _cogl_##handle_type##_get_type () function
automatically defined which returns a GQuark of the handle type, so now
implementing the cogl_is_* funcs is just a case of comparing with
obj->klass->type.
Another outcome of the re-work is that cogl_handle_{ref,unref} are also much
more efficient, and no longer need extending for each handle type added to
cogl. The cogl_##handle_type##_{ref,unref} functions are now deprecated and
are no longer used internally to Clutter or Cogl. Potentially we can remove
them completely before 1.0.
This better reflects the fact that the api manages sets of vertex attributes,
and the attributes really have no implied form. It is only when you use the
attributes to draw that they become mesh like; when you specify how they should
be interpreted, e.g. as triangle lists or fans etc. This rename frees up the
term "mesh", which can later be applied to a concept slightly more fitting.
E.g. at some point it would be nice to have a higher level abstraction that
sits on top of cogl vertex buffers that adds the concept of faces. (Somthing
like Blender's mesh objects.) There have also been some discussions over
particle engines, and these can be defined in terms of emitter faces; so some
other kind of mesh abstraction might be usefull here.
