Commit Graph

149 Commits

Author SHA1 Message Date
Emmanuele Bassi
9e9c615e49 Add runtime debug messages for COGL
Clutter is able to show debug messages written using the CLUTTER_NOTE()
macro at runtime, either by using an environment variable:

  CLUTTER_DEBUG=...

or by using a command line switch:

  --clutter-debug=...
  --clutter-no-debug=...

Both are parsed during the initialization process by using the
GOption API.

COGL would benefit from having the same support.

In order to do this, we need a cogl_get_option_group() function in
COGL that sets up a GOptionGroup for COGL and adds a pre-parse hook
that will check the COGL_DEBUG environment variable. The OptionGroup
will also install two command line switches:

  --cogl-debug
  --cogl-no-debug

With the same semantics of the Clutter ones.

During Clutter initialization, the COGL option group will be attached
to the GOptionContext used to parse the command line options passed
to a Clutter application.

Every debug message written using:

  COGL_NOTE (SECTION, "message format", arguments);

Will then be printed only if SECTION was enabled at runtime.

This whole machinery, like the equivalent one in Clutter, depends on
a compile time switch, COGL_ENABLE_DEBUG, which is enabled at the same
time as CLUTTER_ENABLE_DEBUG. Having two different symbols allows
greater granularity.
2009-02-23 13:00:52 +00:00
Robert Bragg
25fc1b85ab [Cogl] Fixes automatic handling of the GL blend enable state.
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
2009-02-23 10:49:35 +00:00
Robert Bragg
e91fe8817d [Cogl] the cogl_get_*_matrix functions now work with CoglMatrix types
Since the CoglMatrix type was added for supporting texture matrices recently
it made sense to be consistent accross the Cogl API and use the Cogl type
over the GL style GLfloat m[16] arrays.
2009-02-23 10:49:35 +00:00
Emmanuele Bassi
268fa9c7ab Initialize a variable to avoid warnings
The gl_mode variable was not initialized, and the compiler complained
when using the anal-retentive compiler flags.
2009-02-18 18:45:58 +00:00
Robert Bragg
89d8ebcbb0 [Cogl] Renames cogl_paint_init to cogl_clear and adds a cogl_disable_fog function
cogl_paint_init was a bit too miscellaneous; it mainly cleared the color, depth
and stencil buffers but arbitrarily it also disabled fogging and lighting.

It no longer disables lighting, since we know Cogl never enables lighting and
disabling of fog is now handled with a seperate function.

Since I noticed cogl_set_fog was taking a density argument documented as
"Ignored" I've also added a mode argument to cogl_set_fog which exposes the
exponential fog modes which can make use of the density.
2009-02-18 16:00:52 +00:00
Neil Roberts
43a5fef73d Call glActiveTexture and glClientActiveTexture through cogl_get_proc_address
All GL functions that are defined in a version later than 1.1 need to
be called through cogl_get_proc_address because the Windows GL DLL
does not export them to directly link against.
2009-02-16 12:46:36 +00:00
Robert Bragg
06bfc00fbc [Cogl] Renames cogl_fog_set to cogl_set_fog for consistency
More things follow the <object>_set_<property> convention.
2009-02-09 14:15:06 +00:00
Neil Roberts
acdc36a7c5 [cogl-texture] Fix offset to next quad when flushing the log
When the quad log contains multiple textures (such as when a sliced
texture is drawn) it dispatches the log with multiple calls to
flush_quad_batch and walks a pointer along the list of vertices.
However this pointer was being incremented by only one vertex so the
next quad would be drawn with three of the vertices from the last
quad.
2009-02-05 20:29:25 +00:00
Neil Roberts
c50935edca Fix building GLES 2 after the material branch merge
- In cogl-material.h it directly sets the values of the
  CoglMaterialLayerCombineFunc to some GL_* constants. However these
  aren't defined in GLES 2 beacuse it has no fixed function texture
  combining. Instead the CGL_* versions are now used. cogl-defines.h
  now sets these to either the GL_* version if it is available,
  otherwise it directly uses the number.

- Under GLES 2 cogl-material.c needs to access the CoglTexture struct
  so it needs to include cogl-texture-private.h

- There are now #define's in cogl-gles2-wrapper.h to remap the GL
  function names to the wrapper names. These are disabled in
  cogl-gles2-wrapper.c by defining COGL_GLES2_WRAPPER_NO_REMAP.

- Added missing wrappers for glLoadMatrixf and glMaterialfv.

- Renamed the TexEnvf wrapper to TexEnvi because the latter is used
  instead from the material API.
2009-02-02 21:57:41 +00:00
Neil Roberts
da9f956fd1 [cogl] Add an NULL terminator to the call to material_flush_gl_state
This fixes a compiler warning and a potential crash.
2009-01-29 12:21:56 +00:00
Robert Bragg
02127858f3 Another Cogl gl vs gles normalizaion pass
This tries to make a number of files more comparable with the intention of
moving some code into cogl/common/

Files normalized:
 cogl.c
 cogl-context.c
 cogl-context.h
 cogl-texture.c
2009-01-28 17:20:16 +00:00
Robert Bragg
c4b4500059 Changes cogl_rectangle to take x1, y1, x2, y2 args not x1, y1, width, height
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.)
2009-01-28 17:20:15 +00:00
Robert Bragg
1d86b04e06 Adds some debug code to _cogl_journal_flush_quad_batch
The code is #if 0 guarded, but when uncommented it outlines all drawn
rectangles with an un-blended red, green or blue border. This may e.g. help
with debugging texture slicing issues or blending issues, plus it looks quite
cool.
2009-01-28 17:20:15 +00:00
Neil Roberts
ba2fd8a9d3 [cogl-texture] Fix order of tex coords when compensating for waste
When drawing a texture with waste in _cogl_multitexture_unsliced_quad
it scales the texture coordinates so that the waste is not
included. However the formula was the wrong way around so it was
calculating as if the texture coordinates are ordered x1,x2,y1,y2 but
it is actually x1,y1,x2,y2.
2009-01-28 12:57:06 +00:00
Neil Roberts
954c0853cd [cogl-texture] Reset size of vertex log after drawing a polygon
Otherwise trying to render a rectangle after a polygon doesn't work
because it expects the array to be empty when it starts logging
vertices.
2009-01-28 12:24:11 +00:00
Neil Roberts
e6fb58e129 Fix rectangles_with_multitexture_coords for sliced without tex coords
When the texture is sliced it drops back to a fallback function and
passes it the texture coordinates from the rectangle. However if no
tex coords are given it would crash. Now it passes the default
0.0->1.0 tex coords instead.
2009-01-28 12:24:10 +00:00
Neil Roberts
c18d945dc7 Fix _cogl_texture_unsliced_quad when no texture coordinates are given
If no texture coordinates are given then texture_unsliced_quad tries
to generate its own coordinates. However it also tries to read the
texture coordinates to check if they are in [0.0,1.0] range so it will
crash before it reaches that.
2009-01-28 12:24:10 +00:00
Emmanuele Bassi
8dca5c73bc Reuse the layers list
Instead of getting the layers list twice from the Material, we
can reuse the list when we need to retrieve the first layer.
2009-01-28 11:57:49 +00:00
Emmanuele Bassi
31e4ca5733 Fallout from cogl-material merge
When enabling the maintainer CFLAGS the compiler got very angry
at the code that has been merged.
2009-01-27 16:02:04 +00:00
Robert Bragg
a2e52eb3be Support scaling on the z axis with cogl_scale
This simply adds a z argument to cogl_scale and updates clutter-actor.c
to pass 1.0 for the z scale.
2009-01-27 15:20:13 +00:00
Robert Bragg
323eaf3fb3 Merge branch 'cogl-material'
Conflicts:

	clutter/cogl/gl/cogl-texture.c
	clutter/cogl/gles/cogl-primitives.c

* cogl-material:
 clutter-{clone-,}texture weren't updating their material opacity.
 Updates GLES1 support for CoglMaterial
 Normalizes gl vs gles code in preperation for synching material changes
 Removes cogl_blend_func and cogl_alpha_func
 Fully integrates CoglMaterial throughout the rest of Cogl
 [cogl-material] Restore the GL_TEXTURE_ENV_MODE after material_rectangle
 [cogl-material] Make the user_tex_coords parameter of _rectangle const
 [test-cogl-material] Remove return value from material_rectangle_paint
 Add cogl-material.h and cogl-matrix.h to libclutterinclude_HEADERS
 [cogl-material] improvements for cogl_material_rectangle
 [cogl-material] Adds a cogl_material_set_color function
 [cogl-material] Some improvements for how we sync CoglMaterial state with OpenGL
 [cogl-material] Converts clutter-texture/clutter-clone-texture to the material API
 [doc] Hooks up cogl-material reference documentation
 Updates previous GLES multi-texturing code to use CoglMaterial
 Adds a CoglMaterial abstraction, which includes support for multi-texturing
 [doc] Hooks up cogl-matrix reference documentation
 Adds CoglMatrix utility code
 [tests] Adds an interactive unit test for multi-texturing
 [multi-texturing] This adds a new cogl_multi_texture API for GL,GLES1 + GLES2
2009-01-27 15:19:34 +00:00
Robert Bragg
9abf44eac3 Updates GLES1 support for CoglMaterial
This updates cogl/gles in line with the integration of CoglMaterial throughout
Cogl that has been done for cogl/gl.

Note: This is still buggy, but at least it builds again and test-actors works.
Some GLES2 specific changes were made, but these haven't been tested yet.
2009-01-27 14:26:50 +00:00
Robert Bragg
e9a9acd28d Normalizes gl vs gles code in preperation for synching material changes
This changes all GLES code to use the OpenGL function names instead of
the cogl_wrap_* names. For GLES2 we now define the OpenGL name to point
to the wrapper, as opposed to defining the wrapper to point to the
OpenGL name for GLES1.

I've also done a quick pass through gl/cogl.c and gles/cogl.c to make
them more easily comparable. (most of the code is now identical)
2009-01-27 14:26:50 +00:00
Robert Bragg
94077997a7 Removes cogl_blend_func and cogl_alpha_func
The GL blend function and alpha function are now controlled by the material
code, and even internally Cogl should now be using the material API when
it needs control of these.
2009-01-27 14:26:49 +00:00
Robert Bragg
2503f7b321 Fully integrates CoglMaterial throughout the rest of Cogl
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.
2009-01-27 14:26:39 +00:00
Robert Bragg
0c8c273980 Merge commit 'origin/master' into cogl-material
Conflicts:

	clutter/clutter-texture.c
	clutter/cogl/cogl-texture.h
	clutter/cogl/cogl.h.in
	clutter/cogl/common/Makefile.am
	clutter/cogl/gl/Makefile.am
	clutter/cogl/gles/Makefile.am
	clutter/cogl/gles/cogl-gles2-wrapper.c
	clutter/cogl/gles/cogl-gles2-wrapper.h
2009-01-23 15:23:49 +00:00
Emmanuele Bassi
9aedabc6a7 Split maintainer-flags from the compiler flags
The maintainer compiler flags we use trigger warnings and errors
in the autogenerated code that gtk-doc creates to scan the header
and source files. Since we cannot control that, and we must run
a distcheck with both --enable-gtk-doc and --enable-maintainer-flags
turned on, we need to use less-strict compiler flags when inside
the doc/reference subdirectories.

The way to do this is to split the maintainer compiler flags into
their own Makefile variable, called MAINTAINER_CFLAGS. The we
can use $(MAINTAINER_CFLAGS) in the INCLUDES or _CFLAGS sections
of each part of the source directories we wish to check with the
anal retentiveness suited for maintainers.
2009-01-23 13:09:51 +00:00
Emmanuele Bassi
726ee43761 Fix compiler warnings
The maintainer-flags option discovered the usual amount of
collisions and compiler warnings we have to fix in order to
get distcheck to pass.
2009-01-23 13:08:46 +00:00
Neil Roberts
7031791376 Fix some failures from the fixed-to-float script in cogl-texture
The script converted calls to COGL_FIXED_MUL(x,y) to (x*y). However
this fails for cases like this:

 COGL_FIXED_MUL(a + b, c)

which become

 (a + b * c)

The meaning of this is of course different because multiplication has
a higher precedence than addition.

This was causing breakages in cogl_texture_quad_sw when the vertex
coordinates are not in increasing order. This was the case in
test-backface-culling when NPOTs are not available.
2009-01-22 17:44:24 +00:00
Owen W. Taylor
66331b6863 Fix computation of camera distance
Compute the value of the camera distance as exactly half the xx
component of the projection matrix. The heuristically derived
value for 60 degrees was off by about 0.016%, causing noticeable
blurring, and other field of view angles which didn't have the
heuristic adjustment off by much more.

Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
2009-01-22 14:17:16 +00:00
Emmanuele Bassi
799fdf364e Change the COGL texture constructor to use flags
Boolean arguments for functions are pretty evil and usually
lead to combinatorial explosion of parameters in case multiple
settings are added.

In the case of the COGL texture constructors we have a boolean
argument for enabling the auto-mipmapping; it is conceivable that
we might want to add more settings for a COGL texture without
breaking API or ABI compatibility, so the boolean argument should
become a bitmask.

The internals have not been changed: instead of checking for
a non-zero value, we check for a bitmask being set.
2009-01-21 10:14:29 +00:00
Robert Bragg
de41fdd9d1 Renames the mesh api to the "vertex buffer api".
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.
2009-01-20 22:29:35 +00:00
Robert Bragg
4e60f2f5b0 [Automatic fixed-to-float.sh change] Applies a number fixed to float patches
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.
2009-01-20 16:20:54 +00:00
Robert Bragg
3336359abb [Automatic fixed-to-float.sh change] Applies all scripted changes
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.
2009-01-20 16:20:54 +00:00
Robert Bragg
a0c5690d55 Merge commit 'origin/master' into cogl-material
Conflicts:

	clutter/clutter-texture.c
	clutter/cogl/cogl-texture.h
	clutter/cogl/gles/cogl-context.c
	clutter/cogl/gles/cogl-context.h
2009-01-13 13:37:38 +00:00
Emmanuele Bassi
743b5c03dc Merge branch 'master' into async-textures 2009-01-12 14:43:53 +00:00
Emmanuele Bassi
0ca5eeaeae Declare G_LOG_DOMAIN for COGL
In order to get properly namespaced debug and warning messages
inside COGL code we need to define the G_LOG_DOMAIN macro.
2009-01-12 11:21:06 +00:00
Chris Lord
0866b07f30 Update/clean and apply the async-texture patch from bug #1144 2009-01-07 17:02:43 +00:00
Neil Roberts
1530be0af9 Merge branch multiple-texture-rectangle into master
Bug 1289 - Draw multiple glyphs at once

The multiple-texture-rectangle branch adds a new Cogl texture function
called cogl_texture_multiple_rectangles which is used to draw multiple
rectangles out of a texture using a single GL call. This is
significantly faster than drawing the rectangles with individual calls
on some platforms. The Pango renderer now uses this to speed up
rendering.

The conflicts are just due to the whitespace fixes in cb569a5.

Conflicts:

	clutter/cogl/gl/cogl-context.c
	clutter/cogl/gl/cogl-context.h
	clutter/cogl/gl/cogl-texture.c
2009-01-07 16:25:26 +00:00
Neil Roberts
b6470ab900 [cogl-material] Restore the GL_TEXTURE_ENV_MODE after material_rectangle
The rest of Cogl expects the texture mode to be GL_MODULATE so it
needs to be restored after calling cogl_material_rectangle. Otherwise
cogl_texture_rectangle will fail to blend with the Cogl color properly
and all of the labels will be black.
2009-01-06 18:24:57 +00:00
Neil Roberts
cd71b91440 [cogl-material] Make the user_tex_coords parameter of _rectangle const
The array is only used for input so it should be const.
2009-01-06 16:09:55 +00:00
Neil Roberts
ba2257973e Add cogl-material.h and cogl-matrix.h to libclutterinclude_HEADERS
Otherwise they won't get installed
2009-01-06 15:53:35 +00:00
Robert Bragg
0408a5d2c5 [cogl-material] improvements for cogl_material_rectangle
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.
2008-12-24 01:35:33 +00:00
Robert Bragg
e4548bcdc5 [cogl-material] Some improvements for how we sync CoglMaterial state with OpenGL
This flattens the three functions: cogl_material_flush_gl_material_state,
.._flush_gl_alpha_func and .._flush_gl_blend_func into one:
cogl_flush_material_gl_state which doesn't takes a material handle. (the handle
is instead taken from the context.)

This has allows us to avoid re-submitting some state to OpenGL when the
material has not been replaced.

Note: Avoiding redundant state changes for material layers isn't dealt with
in this patch.
2008-12-24 01:33:23 +00:00
Robert Bragg
ef992f55db Merge branch 'master' into cogl-material
Conflicts:

	clutter/cogl/gl/cogl-context.c
	clutter/cogl/gl/cogl-context.h
2008-12-24 00:59:13 +00:00
Robert Bragg
baa63b7c46 White space clean up across a number of files (only removing trailing spaces)
Removed trailing white space from the following files:
- clutter-clone-texture.c
- clutter-texture.c
- clutter-texture.h
- cogl/cogl-texture.h
- cogl/gl/cogl-context.c
- cogl/gl/cogl-texture.c
- cogl/gl/cogl-context.h
2008-12-24 00:48:32 +00:00
Robert Bragg
61b8cc1874 Adds a CoglMaterial abstraction, which includes support for multi-texturing
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.
2008-12-22 16:35:52 +00:00
Robert Bragg
509928cc76 [multi-texturing] This adds a new cogl_multi_texture API for GL,GLES1 + GLES2
Multitexturing allows blending multiple layers of texture data when texturing
some geometry. A common use is for pre-baked light maps which can give nice
lighting effects relativly cheaply. Another is for dot-3 bump mapping, and
another is applying alpha channel masks.

The dot-3 bump mapping would be really nice one day, but currently cogl doesn't
support lighting so that's not dealt with in this patch.

notable limitations:
- It can only texture rectangles a.t.m - and like cogl_texture_rectangle there
is no support for rotated texturing.
- Sliced textures are not supported. I think I've figured out how to handle
layers with different slice sizes at least for rectangular geometry, but I'm
not sure how complex it becomes once rotations are possible and texturing
arbitrary cogl_polygons.
- Except for this new API, cogl still doesn't know about more than one texture
unit, and so has no way of caching any enables related to other units. So that
things don't break it's currently necessary to disable anything to do with
additional units as soon as we are done with them which isn't ideal.
- No clutter API yet.
2008-12-22 16:35:51 +00:00
Neil Roberts
c3e4c6df08 Merge commit 'git-svn' into multiple-texture-rectangle 2008-12-10 12:25:25 +00:00
Neil Roberts
4aea0d6e48 * clutter/cogl/gl/cogl.c:
* clutter/cogl/gl/cogl-defines.h.in:
	* clutter/cogl/gl/cogl-context.h:
	* clutter/cogl/common/cogl-mesh.c: Rename the glBufferDataSub
	function to glBufferSubData. When calling glXGetProcAddress with
	the former Mesa returns a stub dispatch function which will
	segfault if you try to use it. With NVIDIA it returns NULL so
	_cogl_features_init decides the card doesn't have VBO support.
2008-12-10 12:13:20 +00:00