texture: rename texobj flush code as gl specific

This renames the set_filters and set_wrap_mode_parameters texture
virtual functions to gl_flush_legacy_texobj_filters and
gl_flush_legacy_texobj_wrap_modes respectively to clarify that they are
opengl driver specific and that they are only used to support the legacy
opengl apis for setting filters and wrap modes where the state is
associated with texture objects instead of being associated with sampler
objects.

This part of an effort to clearly delimit our abstraction over opengl so
that we can start to consider non-opengl backends for Cogl.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
texture-2d: factor out all GL specific code

This factors out all of the OpenGL specific code in cogl-texture-2d.c
into cogl-texture-2d-gl.c and where necessary adds indirection through
the CoglDriver vtable so that we can eventually start to experiment with
non-OpenGL backends for Cogl.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
blit: avoid using _COGL_GET_CONTEXT

As part of an on-going effort to avoid depending on a global Cogl
context cogl-blit.c now finds the context by looking at
data->src_text->context instead of using the _COGL_GET_CONTEXT macro.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
attribute: Split out GL specific code

As part of an on-going effort to enable non-opengl drivers for Cogl this
splits out the GL specific code in cogl-attribute.c into
cogl/driver/gl/cogl-attribute-gl.c

Reviewed-by: Neil Roberts <neil@linux.intel.com>
Updated Latvian translation
Adds a NOP driver

This adds a new "nop" driver that does nothing. This can be selected at
runtime either with the COGL_DRIVER=nop environment variable or by
passing COGL_DRIVER_NOP to cogl_renderer_set_driver()

Adding the nop driver gives us a way to test workloads without any
driver and hardware overheads which can help us understand how Cogl's
state tracking performs in isolation.

Having a nop driver can also serve as an shell/outline for creating
other drivers later.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
clip-stack: Splits out opengl specific code

As part of an on-going effort to enable non-opengl drivers for Cogl this
splits out the opengl specific code in cogl-clip-stack.c into
cogl/driver/cogl-clip-stack-gl.c

Reviewed-by: Neil Roberts <neil@linux.intel.com>
buffer: move choice about using malloc closer to driver

This moves the decision about whether a buffer should be allocated using
malloc or not into cogl-buffer.c closer to the driver since it seem
there could be other driver specific factors that might also influence
this choice that we don't currently consider.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
Give buffer/bitmap bind functions gl infix

The buffer and bitmap _bind() functions are GL specific so to clarify
that, this patch adds a _gl infix to these functions, though it doesn't
yet move the implementations out into gl specific files.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
buffer: splits out GL specific code

As part of an on-going effort to be able to support non-opengl drivers
for Cogl this splits out the opengl specific code from cogl-buffer.c
into driver/gl/cogl-buffer-gl.c

Reviewed-by: Neil Roberts <neil@linux.intel.com>
Updated POTFILES.in
Updated Latvian translation
Updated Galician translations
pipeline: remove dubious optimization

This removes an optimization that I added at some point, which I'm
pretty certain I only added on a hunch. Reading the description I'm not
really convinced it makes sense to do this given that the fixed vertend
and fragend are currently listed before the glsl vertend and fragend in
the order that we look for a suitable backend. This means unless the
pipeline depends on glsl (e.g. due to an associated snippet) we would
reselect the fixed backend anyway, and if it really did depend on glsl
then we'd notice when we come to flush and switch backends there any way.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
pipeline: remove unused _MASK defines

The COGL_PIPELINE_FRAGEND_XYZ_MASK and COGL_PIPELINE_VERTEND_XYZ_MASK
defines aren't used any more so this patch simply removes them.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
pipeline: remove duplicate defines

There was a spurious duplication of the COGL_PIPELINE_VERTEND_DEFAULT
and COGL_PIPELINE_VERTEND_UNDEFINED defines which this patch removes.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
pipeline: tidy up definition of *END defines

There is some fairly awkward #ifdefing to determine which vertends,
fragends and progends are available at build time. This patch
consolidates the #ifdefing of vertend, fragend and progend defines to
make for slightly easier reading.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
Clearly define 3 progends that own the frag+vertends

This adds a new "fixed-arbfp" progend so we now have 3 distinct ways of
setting up the state of a pipeline:

  » fixed; where the vertex and fragment processing are implemented
    using fixed function opengl apis.
  » fixed-arbfp; where vertex processing is implemented using fixed
    function opengl apis but fragment processing is implemented
    using the ARB Fragment Processing language.
  » glsl; there vertex and fragment processing are both implemented
    using glsl.

This means we avoid unusual, combinations such as glsl for vertex
processing and arbfp for fragment processing, and also avoid pairing
fixed-function vertex processing with glsl fragment processing which we
happen to know hits some awkward code paths in Mesa that lead to poor
performance.

As part of this change, the progend now implies specific vertend and
fragend choices so instead of associating a vertend and fragend with a
pipeline we now just associate a progend choice.

When flushing a pipeline and choosing what progend to use, we now call a
progend->start() method that is able to determine if the vertend and
fragend together will be able to handle the given pipeline so the
vertend and fragend ->start() methods no longer need to return a boolean
status.

Since we now don't need to support glsl used in conjunction with fixed
function this will allow us to avoid ever using OpenGL builtin attribute
names, though this patch doesn't change that yet.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
Updated Serbian translation
Remove the deprecated feature flags

The old system for checking features depended on a bitmask in an
integer which meant we could only have up to 32 features. This was
deprecated in 426c8b8f41. The API for using the legacy feature mask
has already been removed so we might as well also remove the internal
code to maintain the bitmask.

Reviewed-by: Robert Bragg <robert@linux.intel.com>