We now put the color of materials into the vertex array used by the journal
instead of calling glColor() but the number of requests for the material
color were quite expensive so we have changed the material color to
internally be byte components instead of floats to avoid repeat conversions
and added _cogl_material_get_colorubv as a fast-path for the journal to
copy data into the vertex array.
Previously the journal was always flushed at the end of
_cogl_rectangles_with_multitexture_coords, (i.e. the end of any
cogl_rectangle* calls) but now we have broadened the potential for batching
geometry. In ideal circumstances we will only flush once per scene.
In summary the journal works like this:
When you use any of the cogl_rectangle* APIs then nothing is emitted to the
GPU at this point, we just log one or more quads into the journal. A
journal entry consists of the quad coordinates, an associated material
reference, and a modelview matrix. Ideally the journal only gets flushed
once at the end of a scene, but in fact there are things to consider that
may cause unwanted flushing, including:
- modifying materials mid-scene
This is because each quad in the journal has an associated material
reference (i.e. not copy), so if you try and modify a material that is
already referenced in the journal we force a flush first)
NOTE: For now this means you should avoid using cogl_set_source_color()
since that currently uses a single shared material. Later we
should change it to use a pool of materials that is recycled
when the journal is flushed.
- modifying any state that isn't currently logged, such as depth, fog and
backface culling enables.
The first thing that happens when flushing, is to upload all the vertex data
associated with the journal into a single VBO.
We then go through a process of splitting up the journal into batches that
have compatible state so they can be emitted to the GPU together. This is
currently broken up into 3 levels so we can stagger the state changes:
1) we break the journal up according to changes in the number of material layers
associated with logged quads. The number of layers in a material determines
the stride of the associated vertices, so we have to update our vertex
array offsets at this level. (i.e. calling gl{Vertex,Color},Pointer etc)
2) we further split batches up according to material compatability. (e.g.
materials with different textures) We flush material state at this level.
3) Finally we split batches up according to modelview changes. At this level
we update the modelview matrix and actually emit the actual draw command.
This commit is largely about putting the initial design in-place; this will be
followed by other changes that take advantage of the extended batching.
The texture filters are now a property of the material layer rather
than the texture object. Whenever a texture is painted with a material
it sets the filters on all of the GL textures in the Cogl texture. The
filter is cached so that it won't be changed unnecessarily.
The automatic mipmap generation has changed so that the mipmaps are
only generated when the texture is painted instead of every time the
data changes. Changing the texture sets a flag to mark that the
mipmaps are dirty. This works better if the FBO extension is available
because we can use glGenerateMipmap. If the extension is not available
it will temporarily enable automatic mipmap generation and reupload
the first pixel of each slice. This requires tracking the data for the
first pixel.
The COGL_TEXTURE_AUTO_MIPMAP flag has been replaced with
COGL_TEXTURE_NO_AUTO_MIPMAP so that it will default to
auto-mipmapping. The mipmap generation is now effectively free if you
are not using a mipmap filter mode so you would only want to disable
it if you had some special reason to generate your own mipmaps.
ClutterTexture no longer has to store its own copy of the filter
mode. Instead it stores it in the material and the property is
directly set and read from that. This fixes problems with the filters
getting out of sync when a cogl handle is set on the texture
directly. It also avoids the mess of having to rerealize the texture
if the filter quality changes to HIGH because Cogl will take of
generating the mipmaps if needed.
There were a number of functions intended to support creating of new
primitives using materials, but at this point they aren't used outside of
Cogl so until someone has a usecase and we can get feedback on this
API, it's being removed before we release Clutter 1.0.
This removes the following API:
cogl_material_set_blend_factors
cogl_material_set_layer_combine_function
cogl_material_set_layer_combine_arg_src
cogl_material_set_layer_combine_arg_op
These were rather awkward to use, so since it's expected very few people are
using them at this point and it should be straight forward to switch over
to blend strings, the API is being removed before we release Clutter 1.0.
Setting up layer combine functions and blend modes is very awkward to do
programatically. This adds a parser for string based descriptions which are
more consise and readable.
E.g. a material layer combine function could now be given as:
"RGBA = ADD (TEXTURE[A], PREVIOUS[RGB])"
or
"RGB = REPLACE (PREVIOUS)"
"A = MODULATE (PREVIOUS, TEXTURE)"
The simple syntax and grammar are only designed to expose standard fixed
function hardware, more advanced combining must be done with shaders.
This includes standalone documentation of blend strings covering the aspects
that are common to blending and texture combining, and adds documentation
with examples specific to the new cogl_material_set_blend() and
cogl_material_layer_set_combine() functions.
Note: The hope is to remove the now redundant bits of the material API
before 1.0
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
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.
Bug #1460 - Handling of flags in cogl_material_set_color
Cogl automatically enables/disables blending based on whether the source color
has an alhpa < 1.0, or if any textures with an alpha component are in use, but
it wasn't doing it quite right.
At the same time I removed some of the dirty flags which on second thought
are nothing more than micro-optimsations that only helped clutter the code.
thanks to Owen Taylor for reporting the bug
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.
The API has been changed to take an explicit length for the number of
texture coordinates passed, and it's now documented that if there are
more layers to the current material than the number of texture coords
passed, then default coordinates will be generated for the other
layers.
cogl_material_rectangle should now handle the case where a single
sliced texture is supplied as a material layer by falling back to
cogl_texture_rectangle. We are nearly at the point that
cogl_texture_rectangle could be deprecated. A few issues remain
though, such as not considering waste in cogl_material_rectangle.
My previous work to provide muti-texturing support has been extended into
a CoglMaterial abstraction that adds control over the texture combine
functions (controlling how multiple texture layers are blended together),
the gl blend function (used for blending the final primitive with the
framebuffer), the alpha function (used to discard fragments based on
their alpha channel), describing attributes such as a diffuse, ambient and
specular color (for use with the standard OpenGL lighting model), and
per layer rotations. (utilizing the new CoglMatrix utility API)
For now the only way this abstraction is exposed is via a new
cogl_material_rectangle function, that is similar to cogl_texture_rectangle
but doesn't take a texture handle (the source material is pulled from
the context), and the array of texture coordinates is extended to be able
to supply coordinates for each layer.
Note: this function doesn't support sliced textures; supporting sliced
textures is a non trivial problem, considering the ability to rotate layers.
Note: cogl_material_rectangle, has quite a few workarounds, for a number of
other limitations within Cogl a.t.m.
Note: The GLES1/2 multi-texturing support has yet to be updated to use
the material abstraction.
