Previously the fragends had a separate private data pointer which was
used by the GLSL and ARBfp fragends to store a tiny struct containing
a single pointer to the ref-counted shader state. The space for the
private data pointer is reserved in all of the pipelines for all of
the potential backends. The vertends and progends however did this
differently by directly storing the pointer to the ref counted data
using cogl_object_set_user_data. This patch unifies the different
methods so that they all use cogl_object_set_user_data and the
fragends don't bother with the separate tiny allocation for the
private data. The private data pointer array has been removed from
CoglPipeline and the corresponding fragend virtual to free the private
data has also been removed because this can instead be done with the
destroy notify from the object user data.
The variable names used have been unified so that all of the vertends
and fragends name their data struct CoglPipelineShaderState and use a
variable called shader_state to refer to it. The progend uses
CoglPipelineProgramState and a variable called program_state.
This should also fix two potential bugs. the ARBfp fragend was
apprently leaking a reference to the private state when it creates the
private data because it was adding a reference before stroring the
pointer to the newly allocated data but the ref count is already set
to 1 on creation. The other potential bug is that the free function
for CoglPipeline was only calling the free_priv virtual for the
currently used fragend of the pipeline. The design of the fragends is
meant to allow a pipeline to have multiple fragend priv datas because
a child pipeline could be attaching its fragend data to the ancestor
and its allowed to pick a different fragend.
The GL or GLES library is now dynamically loaded by the CoglRenderer
so that it can choose between GL, GLES1 and GLES2 at runtime. The
library is loaded by the renderer because it needs to be done before
calling eglInitialize. There is a new environment variable called
COGL_DRIVER to choose between gl, gles1 or gles2.
The #ifdefs for HAVE_COGL_GL, HAVE_COGL_GLES and HAVE_COGL_GLES2 have
been changed so that they don't assume the ifdefs are mutually
exclusive. They haven't been removed entirely so that it's possible to
compile the GLES backends without the the enums from the GL headers.
When using GLX the winsys additionally dynamically loads libGL because
that also contains the GLX API. It can't be linked in directly because
that would probably conflict with the GLES API if the EGL is
selected. When compiling with EGL support the library links directly
to libEGL because it doesn't contain any GL API so it shouldn't have
any conflicts.
When building for WGL or OSX Cogl still directly links against the GL
API so there is a #define in config.h so that Cogl won't try to dlopen
the library.
Cogl-pango previously had a #ifdef to detect when the GL backend is
used so that it can sneakily pass GL_QUADS to
cogl_vertex_buffer_draw. This is now changed so that it queries the
CoglContext for the backend. However to get this to work Cogl now
needs to export the _cogl_context_get_default symbol and cogl-pango
needs some extra -I flags to so that it can include
cogl-context-private.h
cogl-ext-functions.h now contains definitions for all of the core GL
and GLES functions that we would normally link to directly. All of the
code has changed to access them through the cogl context pointer. The
GE macro now takes an extra parameter to specify the context because
the macro itself needs to make GL calls but various points in the Cogl
source use different names for the context variable.
When flushing a pipeline that has more layers than the previous
pipeline, the fixed function fragend is supposed to detect that the
texture unit previously had no texture target enabled and then enable
it. However the logic for checking whether the unit was enabled was
broken due to a typing failure when unit->enabled and
unit->current_gl_target were combined into one value in commit
6b7139b0. This was breaking some of the conformance tests when the
fixed function fragend is used.
https://bugzilla.gnome.org/show_bug.cgi?id=650979
The CoglDebugFlags are now stored in an array of unsigned ints rather
than a single variable. The flags are accessed using macros instead of
directly peeking at the cogl_debug_flags variable. The index values
are stored in the enum rather than the actual mask values so that the
enum doesn't need to be more than 32 bits wide. The hope is that the
code to determine the index into the array can be optimized out by the
compiler so it should have exactly the same performance as the old
code.
There are several places where we need to compare the texture state of a
pipeline and sometimes we need to take into consideration if the
underlying texture has changed but other times we may only care to know
if the texture target has changed.
For example the fragends typically generate programs that they want to
share with all pipelines with equivalent fragment processing state, and
in this case when comparing pipelines we only care about the texture
targets since changes to the underlying texture won't affect the
programs generated.
Prior to this we had tried to handle this by passing around some special
flags to various functions that evaluate pipeline state to say when we
do/don't care about the texture data, but this wasn't working in all
cases and was more awkward to manage than the new approach.
Now we simply have two state bits:
COGL_PIPELINE_LAYER_STATE_TEXTURE_TARGET and
COGL_PIPELINE_LAYER_STATE_TEXTURE_DATA and CoglPipelineLayer has an
additional target member. Since all the appropriate code takes masks of
these state bits to determine what to evaluate we don't need any extra
magic flags.
The GLSL vertend is mostly only useful for GLES2. The fixed function
vertend is kept at higher priority than the GLSL vertend so it is
unlikely to be used in any other circumstances.
Previously enabling and disabling textures was done whatever the
backend in cogl-pipeline-opengl. However enabling and disabling
texture targets only has any meaning if no fragment shaders are being
used so this patch moves the code to cogl-pipeline-fragend-fixed.
The GLES2 wrapper has also been changed to ignore enabledness when
deciding whether to update texture coordinate attribute pointers.
The current Cogl pipeline backends are entirely concerned with the
fragment processing state. We also want to eventually have separate
backends to generate shaders for the vertex processing state so we
need to rename the fragment backends. 'Fragend' is a somewhat weird
name but we wanted to avoid ending up with illegible symbols like
CoglPipelineFragmentBackendGlslPrivate.
