In order to cope with the situation where an application renders with
a PangoLayout, makes some changes and then renders again with the same
layout, CoglPangoRenderer needs to detect that the changes have
occured so that it can recreate the display list. This is acheived by
keeping a reference to the first line of the layout. When the layout
is changed Pango will clear the layout pointer in the first line and
create a new line. So if the layout pointer in the line becomes NULL
then we know the layout has changed. This trick was suggested by
Behdad Esfahbod in this email:
http://mail.gnome.org/archives/gtk-i18n-list/2009-May/msg00019.html
When a position is given to cogl_pango_render_layout_subpixel it
translates the GL matrix by the coordinates. However it was not
dividing by PANGO_SCALE so the coordinates were completely wrong.
When rendering a pango layout CoglPangoRenderer now records the
operations into a list called a CoglPangoDisplayList. The entries in
the list are either glyph renderings from a texture, rectangles or
trapezoids. Multiple consecutive glyph renderings from the same glyph
cache texture are combined into a single entry. Note the
CoglPangoDisplayList has nothing to do with a GL display list.
After the display list is built it is attached to the PangoLayout with
g_object_set_qdata so that next time the layout is rendered it can
bypass rebuilding it.
The glyph rendering entries are drawn via a VBO. The VBO is attached
to the display list so it can be used multiple times. This makes the
common case of rendering a PangoLayout contained in a single texture
subsequent times usually boil down to a single call to glDrawArrays
with an already uploaded VBO.
The VBOs are accessed via the cogl_vertex_buffer API so if VBOs are
not available in GL it will resort to a fallback.
Note this will fall apart if the pango layout is altered after the
first render. I can't find a way to detect when the layout is
altered. However this won't affect ClutterText because it creates a
new PangoLayout whenever any properties are changed.
Since the Cogl material branch merge when changing the color of a part
using pango attributes (such as using <span color="red" /> markup)
then it wouldn't return to the default color for the rest of the
layout. pango_renderer_get_color returns NULL if there is no color
override in which case it needs to revert to the color specified as
the argument to cogl_pango_render_layout. The 'color' member of
CoglPangoRenderer has been reinstated to store that default color and
now cogl_pango_render_set_color_for_part is the only place that sets
the material color.
The CoglPango code falls under the COGL "jurisdiction"; this means
that it cannot include Clutter headers unless strictly necessary.
The CoglPangoRenderer code was using the CLUTTER_NOTE() macro. Now
that COGL has it's own COGL_NOTE() similar macro, CoglPango should
use that and avoid including clutter-debug.h (which pulls in
clutter-private.h which in turn pulls in clutter-actor.h).
A new flag, COGL_DEBUG_PANGO, has been added to the COGL debug
flags.
This makes it consistent with cogl_rectangle_with_{multi,}texture_coords.
Notably the reason cogl_rectangle_with_{multi,}texture_coords wasn't changed
instead is that the former approach lets you describe back facing rectangles.
(though technically you could pass negative width/height values to achieve
this; it doesn't seem as neat.)
This glues CoglMaterial in as the fundamental way that Cogl describes how to
fill in geometry.
It adds cogl_set_source (), which is used to set the material which will be
used by all subsequent drawing functions
It adds cogl_set_source_texture as a convenience for setting up a default
material with a single texture layer, and cogl_set_source_color is now also
a convenience for setting up a material with a solid fill.
"drawing functions" include, cogl_rectangle, cogl_texture_rectangle,
cogl_texture_multiple_rectangles, cogl_texture_polygon (though the
cogl_texture_* funcs have been renamed; see below for details),
cogl_path_fill/stroke and cogl_vertex_buffer_draw*.
cogl_texture_rectangle, cogl_texture_multiple_rectangles and
cogl_texture_polygon no longer take a texture handle; instead the current
source material is referenced. The functions have also been renamed to:
cogl_rectangle_with_texture_coords, cogl_rectangles_with_texture_coords
and cogl_polygon respectivly.
Most code that previously did:
cogl_texture_rectangle (tex_handle, x, y,...);
needs to be changed to now do:
cogl_set_source_texture (tex_handle);
cogl_rectangle_with_texture_coords (x, y,....);
In the less likely case where you were blending your source texture with a color
like:
cogl_set_source_color4ub (r,g,b,a); /* where r,g,b,a isn't just white */
cogl_texture_rectangle (tex_handle, x, y,...);
you will need your own material to do that:
mat = cogl_material_new ();
cogl_material_set_color4ub (r,g,b,a);
cogl_material_set_layer (mat, 0, tex_handle));
cogl_set_source_material (mat);
Code that uses the texture coordinates, 0, 0, 1, 1 don't need to use
cog_rectangle_with_texure_coords since these are the coordinates that
cogl_rectangle will use.
For cogl_texture_polygon; as well as dropping the texture handle, the
n_vertices and vertices arguments were transposed for consistency. So
code previously written as:
cogl_texture_polygon (tex_handle, 3, verts, TRUE);
need to be written as:
cogl_set_source_texture (tex_handle);
cogl_polygon (verts, 3, TRUE);
All of the unit tests have been updated to now use the material API and
test-cogl-material has been renamed to test-cogl-multitexture since any
textured quad is now technically a test of CoglMaterial but this test
specifically creates a material with multiple texture layers.
Note: The GLES backend has not been updated yet; that will be done in a
following commit.
To deal with all the corner cases that couldn't be scripted a number of patches
were written for the remaining 10% of the effort.
Note: again no API changes were made in Clutter, only in Cogl.
This is the result of running a number of sed and perl scripts over the code to
do 90% of the work in converting from 16.16 fixed to single precision floating
point.
Note: A pristine cogl-fixed.c has been maintained as a standalone utility API
so that applications may still take advantage of fixed point if they
desire for certain optimisations where lower precision may be acceptable.
Note: no API changes were made in Clutter, only in Cogl.
Overview of changes:
- Within clutter/* all usage of the COGL_FIXED_ macros have been changed to use
the CLUTTER_FIXED_ macros.
- Within cogl/* all usage of the COGL_FIXED_ macros have been completly stripped
and expanded into code that works with single precision floats instead.
- Uses of cogl_fixed_* have been replaced with single precision math.h
alternatives.
- Uses of COGL_ANGLE_* and cogl_angle_* have been replaced so we use a float for
angles and math.h replacements.
The glyphs are queued into an array of rectangles instead of being
drawn directly. Whenever a different texture is used or the sequence
is complete the array is flushed.
This is based on a patch from Owen Taylor.
* clutter/cogl/cogl-color.h:
* clutter/cogl/cogl-path.h:
* clutter/cogl/cogl-types.h:
* clutter/cogl/common/cogl-color.c: Deprecated cogl_color()
in favour of cogl_set_source_color() and friends; store the
CoglColor components as unsigned bytes instead of fixed point
normalized values; add functions for allocating, copying and
freeing CoglColor, for use of language bindings.
* clutter/cogl/cogl.h.in:
* clutter/cogl/cogl-deprecated.h: Added cogl-deprecated.h,
an header file containing the deprecation symbols similar
to clutter-deprecated.h.
* clutter/cogl/gl/Makefile.am:
* clutter/cogl/gl/cogl-texture.c:
* clutter/cogl/gl/cogl.c:
* clutter/cogl/gles/Makefile.am:
* clutter/cogl/gles/cogl-texture.c:
* clutter/cogl/gles/cogl.c: Update the GL and GLES implementations
of COGL after the CoglColor changes.
* clutter/clutter-actor.c:
* clutter/clutter-clone-texture.c:
* clutter/clutter-entry.c:
* clutter/clutter-label.c:
* clutter/clutter-rectangle.c:
* clutter/clutter-texture.c: Do not use CoglColor whenever it
is possible, and use cogl_set_source_color4ub() instead.
* clutter/pango/cogl-pango-render.c: Ditto as above.
* doc/reference/clutter/subclassing-ClutterActor.xml:
* doc/reference/cogl/cogl-sections.txt: Update the documentation.
* tests/interactive/test-cogl-offscreen.c:
* tests/interactive/test-cogl-primitives.c:
* tests/interactive/test-cogl-tex-convert.c:
* tests/interactive/test-cogl-tex-foreign.c:
* tests/interactive/test-cogl-tex-getset.c:
* tests/interactive/test-cogl-tex-polygon.c:
* tests/interactive/test-cogl-tex-tile.c:
* tests/interactive/test-paint-wrapper.c: Drop the usage of
CoglColor whenever it is possible.
