As part of an effort towards being able to write non-opengl based
backends for Cogl this moves most of the opengl specific code under
drivers/gl. drivers/gl and drivers/gles have been moved to
drivers/gl/gl and drivers/gl/es respectively.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 7dc482facb0a265c7f48660079e7e12dd7a2813e)
This splits out most of the OpenGL specific code from cogl-framebuffer.c
into cogl-framebuffer-gl.c and extends the CoglDriverVtable interface
for cogl-framebuffer.c to use.
There are hopes to support several different backends for Cogl
eventually to hopefully get us closer to the metal so this makes some
progress in organizing which parts of Cogl are OpenGL specific so these
parts can potentially be switched out later.
The only remaining use of OpenGL still in cogl-framebuffer.c is to
handle cogl_framebuffer_read_pixels.
This commit introduces some new framebuffer api to be able to
enable texture based depth buffers for a framebuffer (currently
only supported for offscreen framebuffers) and once allocated
to be able to retrieve the depth buffer as a texture for further
usage, say, to implement shadow mapping.
The API works as follow:
* Before the framebuffer is allocated, you can request that a depth
texture is created with
cogl_framebuffer_set_depth_texture_enabled()
* cogl_framebuffer_get_depth_texture() can then be used to grab a
CoglTexture once the framebuffer has been allocated.
This adds two new configuration environment variables:
COGL_DISABLE_GL_EXTENSIONS and
COGL_OVERRIDE_GL_VERSION
The variables can also be set in the cogl.conf file using the same
names.
The first one is a list of GL extension names separated by commas.
When set Cogl will assume any extension listed here is not available
by removing it from the string returned from
glGetString(GL_EXTENSIONS). If the string is set in both the config
file and the environment variable then the union of the two lists will
be used.
The second overrides the value returned from glGetString(GL_VERSION).
If the string is set in both places the version from the environment
variable will take priority.
These are sometimes useful for debugging Cogl to test the various
combinations of extensions. It could also be useful to work around
driver bugs where an extension is badly supported and it would be
better not to use it.
The variables in cogl-config that just set a global char * variable
have been put together in an array instead of having a separate blob
of code for each one in order to make it simpler to add new variables.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit ec69c2dc576c78664e0b73879365cb7414ecf441)
According to the EGL spec, eglGetProcAddress should only be used to
retrieve extension functions. It also says that returning non-NULL
does not mean the extension is available so you could interpret this
as saying that the function is allowed to return garbage for core
functions. This seems to happen at least for the Android
implementation of EGL.
To workaround this the winsys's are now passed down a flag to say
whether the function is from the core API. This information is already
in the gl-prototypes headers as the minimum core GL version and as a
pair of flags to specify whether it is available in core GLES1 and
GLES2. If the function is in core the EGL winsys will now avoid using
eglGetProcAddress and always fallback to querying the library directly
with the GModule API.
The GLX winsys is left alone because glXGetProcAddress apparently
supports querying core API and extension functions.
The WGL winsys could ideally be changed because wglGetProcAddress
should also only be used for extension functions but the situation is
slightly different because WGL considers anything from GL > 1.1 to be
an extension so it would need a bit more information to determine
whether to query the function directly from the library.
The SDL winsys is also left alone because it's not as easy to portably
determine which GL library SDL has chosen to load in order to resolve
the symbols directly.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit 72089730ad06ccdd38a344279a893965ae68cec1)
Since we aren't able to break API on the 1.12 branch
cogl_get_proc_address is still supported but isn't easily able to
determine whether the given name corresponds to a core symbol or
not. For now we just assume the symbol being queried isn't part
of the core GL api and update the documentation accordingly.
Some drivers have good support for GLSL but don't have the complete
set of features needed to advertise GL 2.0 support. We should accept
the three old GLSL extensions (GL_ARB_shader_objects,
GL_ARB_vertex_shader and GL_ARB_fragment_shader) to support shaders on
these drivers.
This patch splits the shader functions into four sections :- those
that are provided only in GL 2.0, those that have the same name in the
shader objects extension, those that are provided by the vertex
shader extension (they all share the same name) and those that have a
different name in the shader objects extension.
If GL 2.0 is not supported but all three of the extensions are then
the pointers to the GL2-only functions will be replaced to point to
the equivalent functions from the extensions. That way the rest of the
Cogl source doesn't have to worry about the name differences.
https://bugzilla.gnome.org/show_bug.cgi?id=677078
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit 71ecb51bd20dc3053b4221961b57e5a2b1029bdf)
Until now, we hardcoded the internal format to GL_RGBA and used the
internal format returned by pixel_format_to_gl() as the format for
checking the texture size and format we're asked to create.
Let's use the proper internal format/format from now on.
This is needed as a later patch introduces DEPTH and DEPTH_STENCIL
textures.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit ec45f60ee2545f88302da314bcdbe1439c4ba9c9)
This detects when we are running on any of Mesa's software rasterizer
backends and disables use of glBlitFramebuffer and glXCopySubBuffer.
Both of these currently result in full-screen copies so there's little
point in using these to optimize how much of the screen we present.
To help ensure we re-evaluate this workaround periodically we have added
a comment marker of "ONGOING BUG" above the workaround and added a note
to our RELEASING document that says we should grep for this marker and
write a NEWS section about ongoing bug workarounds.
https://bugzilla.gnome.org/show_bug.cgi?id=674208
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 11f2f6ebb42398978ec8dd92b3c332ae8140a728)
The coding style has for a long time said to avoid using redundant glib
data types such as gint or gchar etc because we feel that they make the
code look unnecessarily foreign to developers coming from outside of the
Gnome developer community.
Note: When we tried to find the historical rationale for the types we
just found that they were apparently only added for consistent syntax
highlighting which didn't seem that compelling.
Up until now we have been continuing to use some of the platform
specific type such as gint{8,16,32,64} and gsize but this patch switches
us over to using the standard c99 equivalents instead so we can further
ensure that our code looks familiar to the widest range of C developers
who might potentially contribute to Cogl.
So instead of using the gint{8,16,32,64} and guint{8,16,32,64} types this
switches all Cogl code to instead use the int{8,16,32,64}_t and
uint{8,16,32,64}_t c99 types instead.
Instead of gsize we now use size_t
For now we are not going to use the c99 _Bool type and instead we have
introduced a new CoglBool type to use instead of gboolean.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 5967dad2400d32ca6319cef6cb572e81bf2c15f0)
Removing CoglHandle has been an on going goal for quite a long time now
and finally this patch removes the last remaining uses of the CoglHandle
type and the cogl_handle_ apis.
Since the big remaining users of CoglHandle were the cogl_program_ and
cogl_shader_ apis which have replaced with the CoglSnippets api this
patch removes both of these apis.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 6ed3aaf4be21d605a1ed3176b3ea825933f85cf0)
Since the original patch was done after removing deprecated API
this back ported patch doesn't affect deprecated API and so
actually this cherry-pick doesn't remove all remaining use of
CoglHandle as it did for the master branch of Cogl.
The Intel driver currently has an optimisation when calling
glReadPixels into a PBO so that it will use a blit instead of the Mesa
fallback path. However this only works if the GL_PACK_ALIGNMENT is
exactly 1, even if this would be equivalent to a higher alignment
value because the bpp*width is already aligned. To make it more likely
to hit this fast path, we now detect this situation and explicitly use
an alignment of 1. To make this work the texture driver needs to be
passed down the bpp*width as well as the rowstride when configuring
the alignment.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
GL_ARB_sampler_objects provides a GL object which overrides the
sampler state part of a texture object with different values. The
sampler state that Cogl currently exposes is the wrap modes and
filters. Cogl exposes the state as part of the pipeline layer state
but without this extension GL only exposes it as part of the texture
object state. This means that it won't work to use a single texture
multiple times in one primitive with different sampler states. It also
makes switching between different sampler states with a single texture
not terribly efficient because it has to change the texture object
state every time.
This patch adds a cache for sampler states in a shared hash table
attached to the CoglContext. The entire set of parameters for the
sampler state is used as the key for the hash table. When a unique
state is encountered the sampler cache will create a new entry,
otherwise it will return a const pointer to an existing entry. That
means we can have a single pointer to represent any combination of
sampler state.
Pipeline layers now just store this single pointer rather than storing
all of the sampler state. The two separate state flags for wrap modes
and filters have now been combined into one. It should be faster to
compare the sampler state now because instead of comparing each value
it can just compare the pointers to the cached sampler entries. The
hash table of cached sampler states should only need to perform its
more expensive hash on the state when a property is changed on a
pipeline, not every time it is flushed.
When the sampler objects extension is available each cached sampler
state will also get a sampler object to represent it. The common code
to flush the GL state will now simply bind this object to a unit
instead of flushing the state though the CoglTexture when possible.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
Cogl already had a vtable for the texture driver. This ended up being
used for some things that are not strictly related to texturing such
as converting between pixel formats and GL enums. Some other functions
that are driver dependent such as updating the features were not
indirected through a vtable but instead switched directly by looking
at the ctx->driver enum value. This patch normalises to the two uses
by adding a separate vtable for driver functions not related to
texturing and moves the pixel format conversion functions to it from
the texture driver vtable. It also adds a context parameter to all of
the functions in the new driver vtable so that they won't have to rely
on the global context.
The assert could use a 'default:' label but that would stop GCC from
giving a warning when a new enum value is added.
https://bugzilla.gnome.org/show_bug.cgi?id=671016
Reviewed-by: Robert Bragg <robert@linux.intel.com>
The GL_DEPTH_STENCIL format for renderbuffers is defined in a separate
extension from GL_EXT_framebuffer_object so we probably shouldn't
being trying to use it unless that extension is advertised. This just
replaces the check for whether the driver is GL for a check for a
private feature flag before trying GL_DEPTH_STENCIL. The private
feature flag is set if the extension is available on GL.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
The cogl.h header is meant to be the public header for including the 1.x
api used by Clutter so we should stop using that as a convenient way to
include all likely prototypes and typedefs. Actually we already do a
good job of listing the specific headers we depend on in each of the .c
files we have so mostly this patch just strip out the redundant
includes for cogl.h with a few fixups where that broke the build.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
The _cogl_texture_driver_pixel_format_to_gl functions for OpenGL and
OpenGLES convert CoglPixelFormats into corresponding gl enums that can
be used to upload texture data. Previously we were only handling a few
specific formats but this patch updates the functions to handle all the
formats we know about. The functions now also switch() on the format so
that we will get build time warnings if we forget to handle new formats
in these functions.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
https://bugzilla.gnome.org/show_bug.cgi?id=660188
edit: tweaked the internal format returned by pixel_format_to_gl();
handled 1010102 formats and rebased -- Robert Bragg
Reviewed-by: Robert Bragg <robert@linux.intel.com>
Reviewed-by: Neil Roberts <neil@linux.intel.com>
This moves _cogl_get_format_bpp from cogl-bitmap.c to cogl.c and renames
it to _cogl_pixel_format_get_bytes_per_pixel. This makes it clearer that
it doesn't return bits per pixel and makes the naming consistent with
other cogl api. The prototype has been moved to cogl-private.h since it
seems we should be aiming to get rid of cogl-internal.h at some point.
The patch also adds a simple gtk-doc comment since we might want to make
this api public.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
This adds COGL_PIPELINE_WRAP_MODE_MIRRORED_REPEAT enum so that mirrored
texture repeating can be used. This also adds support for emulating the
MIRRORED_REPEAT mode via the cogl-spans API so it can also be used with
meta textures such as sliced and atlas textures.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
Currently features are represented as bits in a 32bit mask so we
obviously can't have more than 32 features with that approach. The new
approach is to use the COGL_FLAGS_ macros which lets us handle bitmasks
without a size limit and we change the public api to accept individual
feature enums instead of a mask. This way there is no limit on the
number of features we can add to Cogl.
Instead of using cogl_features_available() there is a new
cogl_has_feature() function and for checking multiple features there is
cogl_has_features() which takes a zero terminated vararg list of
features.
In addition to being able to check for individual features this also
adds a way to query all the features currently available via
cogl_foreach_feature() which will call a callback for each feature.
Since the new functions take an explicit context pointer there is also
no longer any ambiguity over when users can first start to query
features.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
Cogl provides a consistent public interface regardless of whether the
underlying GL driver supports VBOs so it doesn't make much sense to have
this feature as part of the public api. We can't break the api by
removing the enum but at least we no longer ever set the feature flag.
We now have a replacement private feature flag COGL_PRIVATE_FEATURE_VBOS
which cogl now checks for internally.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
Cogl provides a consistent public interface regardless of whether the
underlying GL driver supports PBOs so it doesn't make much sense to have
this feature as part of the public api. We can't break the api by
removing the enum but at least we no longer ever set the feature flag.
We now have a replacement private feature flag COGL_PRIVATE_FEATURE_PBOS
which cogl now checks for internally.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
Cogl doesn't currently expose public api for clip planes so it
doesn't make much sense to have this feature as part of the public api.
We can't break the api by removing the enum but at least we no longer
ever set the feature flag.
We now have a replacement private feature flag
COGL_PRIVATE_FEATURE_FOUR_CLIP_PLANES which cogl now checks for
internally.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
Cogl doesn't expose public api for blitting between framebuffers so it
doesn't make much sense to have this feature as part of the public api
currently. We can't break the api by removing the enum but at least we
no longer ever set the feature flag.
We now have a replacement private feature flag
COGL_PRIVATE_FEATURE_OFFSCREEN_BLIT which cogl now checks for
internally.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
Although we have to leave the COGL_FEATURE_STENCIL_BUFFER enum as part
of the public api we no longer ever set this feature flag.
Cogl doesn't currently expose the concept of a stencil buffer in the
public api (we only indirectly expose it via the clip stack api) so it
doesn't make much sense to have a stencil buffer feature flag.
We now have a COGL_PRIVATE_FEATURE_STENCIL_BUFFER flag instead which
we can check when we need to use the buffer for clipping.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
Actual support for yuv textures isn't fully plumbed into Cogl currently
so the check for GL_MESA_ycbcr_texture is meaningless. For now we just
remove the check.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
This adds support for multisample rendering to offscreen framebuffers.
After an offscreen framebuffer is first instantiated using
cogl_offscreen_new_to_texture() it is then possible to use
cogl_framebuffer_set_samples_per_pixel() to request multisampling before
the framebuffer is allocated. This also adds
cogl_framebuffer_resolve_samples() for explicitly resolving point
samples into pixels. Even though we currently only support the
IMG_multisampled_render_to_texture extension which doesn't require an
explicit resolve, the plan is to also support the
EXT_framebuffer_multisample extension which uses the framebuffer_blit
extension to issue an explicit resolve.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
The check for the point sprite feature got lost when the feature
functions header was combined for GL and GLES in dae02a99a.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
Previously, _cogl_get_proc_address had a fallback to resolve the
symbol using g_module_open(NULL) to get the symbol from anywhere in
the address space. The EGL backend ends up using this on some drivers
because eglGetProcAddress isn't meant to return a pointer for core
functions. This causes problems if something in the process is linking
against a different GL library, for example Cairo may be linking
against libGL itself. In this case it may end up resolving symbols
from the GL library even if GLES is being used.
This patch removes the fallback. The EGL version now has its own
fallback instead which passes the existing libgl_module from the
renderer to g_module_symbol so that it should only get symbols from
that library or its dependency chain. The GLX and WGL winsys only call
glXGetProcAddress and wglGetProcAddress. The stub winsys does however
continue using the global symbol lookup.
The internal _cogl_get_proc_address function has been renamed to
_cogl_renderer_get_proc_address because it needs a connected renderer
to work so it could be considered to be a renderer method. The pointer
to the renderer is passed down to the winsys backends so that it can
use the data attached to the renderer to get the module pointers.
https://bugzilla.gnome.org/show_bug.cgi?id=655412
Reviewed-by: Robert Bragg <robert@linux.intel.com>
The _cogl_context_check_gl_version function is meant to be called once
Cogl has a GL context so that it can check whether the context found
is supported by Cogl. However, only the stub winsys was calling this
and it was doing it before Cogl had a chance to retrieve the function
pointer for glString so it would just crash. This patch combines the
two functions into one so that _cogl_context_update_features returns a
gboolean and a GError. Then it can just check the context itself.
https://bugzilla.gnome.org/show_bug.cgi?id=654440
Reviewed-by: Robert Bragg <robert@linux.intel.com>
cogl_read_pixels returns image data in a top-down memory order, but
because OpenGL normally returns pixel data in a bottom-up order we
have to flip the data before returning it to the user. If the OpenGL
driver supports the GL_MESA_pack_invert extension though we can ask the
driver to return the data in a top-down order in the first place.
Signed-off-by: Neil Roberts <neil@linux.intel.com>
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
The texture driver functions are now accessed through a vtable pointed
to by a struct in the CoglContext so that eventually it will be
possible to compile both the GL and GLES texture drivers into a single
binary and then select between them at runtime.
Since the GL function pointers have move to the root of CoglContext,
the driver specific data for GLES became empty and the GL data had
only one varible which apparently nothing was using. It's therefore
convenient to remove the private driver data to make it easier to have
a build of Cogl which enables both GL and GLES support. If we ever
need driver private data later we might want to use
cogl_object_set_user_data instead.
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.
Instead of storing all of the feature function pointers in the driver
specific data of the CoglContext they are now all stored directly in
CoglContext. There is a single header containing the description of
the functions which gets included by cogl-context.h. There is a single
function in cogl-feature-private.c to check for all of these
functions.
The name of the function pointer variables have been changed from
ctx->drv.pf_glWhatever to just ctx->glWhatever.
The feature flags that get set when an extension is available are now
separated from the table of extensions. This is necessary because
different extensions can mean different things on GLES and GL. For
example, having access to glMapBuffer implies read and write support
on GL but only write support on GLES. The flags are instead set in the
driver specific init function by checking whether the function
pointers were successfully resolved.
_cogl_feature_check has been changed to assume the feature is
supported if any of the listed extensions are available instead of
requiring all of them. This makes it more convenient to specify
alternate names for the extension. Nothing else had previously listed
more than one name for an extension so this shouldn't cause any
problems.
This adds an internal texture_2d constructor that can wrap an EGLImage
as a CoglTexture2D. The plan is to utilize this for texture-from-pixmap
support with EGL as well as creating textures from wayland buffers.
Instead of simply extending the cogl_pipeline_ namespace to add api for
controlling the depth testing state we now break the api out. This adds
a CoglDepthState type that can be stack allocated. The members of the
structure are private but we have the following API to setup the state:
cogl_depth_state_init
cogl_depth_state_set_test_enabled
cogl_depth_state_get_test_enabled
cogl_depth_state_set_test_function
cogl_depth_state_get_test_function
cogl_depth_state_set_writing_enabled
cogl_depth_state_get_writing_enabled
cogl_depth_state_set_range
cogl_depth_state_get_range
This removes the following experimental API which is now superseded:
cogl_material_set_depth_test_enabled
cogl_material_get_depth_test_enabled
cogl_material_set_depth_test_function
cogl_material_get_depth_test_function
cogl_material_set_depth_writing_enabled
cogl_material_get_depth_writing_enabled
cogl_material_set_depth_range
cogl_material_get_depth_range
Once a CoglDepthState structure is setup it can be set on a pipeline
using cogl_pipeline_set_depth_state().
This is a workaround for a bug on OSX for some radeon hardware that
we can't verify and the referenced bug link is no longer valid.
If this is really still a problem then a new bug should be opened and we
can look at putting the fix in some more appropriate place than
cogl-gl.c
This migrates all the GLX window system code down from the Clutter
backend code into a Cogl winsys. Moving OpenGL window system binding
code down from Clutter into Cogl is the biggest blocker to having Cogl
become a standalone 3D graphics library, so this is an important step in
that direction.
This moves the functionality of _cogl_create_context_driver from
driver/{gl,gles}/cogl-context-driver-{gl,gles}.c into
driver/{gl,gles}/cogl-{gl,gles}.c as a static function called
initialize_context_driver.
cogl-context-driver-{gl,gles}.[ch] have now been removed.
GLES has an extension called GL_OES_mapbuffer to support mapping
buffer objects but only for writing. Cogl now has two new feature
flags to advertise whether mapping for reading and writing is
supported. Under OpenGL, these features are always set if the VBO
extension is advertised and under GLES only the write flag is set if
the GL_OES_mapbuffer extension is advertised.
The features_cached member of CoglContext is intended to mark when
we've calculated the features so that we know if they are ready in
cogl_get_features. However we always intialize the features while
creating the context so features_cached will never be FALSE so it's
not useful. We also had the odd behaviour that the COGL_DEBUG feature
overrides were only applied in the first call to
cogl_get_features. However there are other functions that use the
feature flags such as cogl_features_available that don't use this
function so in some cases the feature flags will be interpreted before
the overrides are applied. This patch makes it always initialize the
features and apply the overrides immediately while creating the
context. This fixes a problem with COGL_DEBUG=disable-arbfp where the
first material flushed is done before any call to cogl_get_features so
it may still use ARBfp.
This applies an API naming change that's been deliberated over for a
while now which is to rename CoglMaterial to CoglPipeline.
For now the new pipeline API is marked as experimental and public
headers continue to talk about materials not pipelines. The CoglMaterial
API is now maintained in terms of the cogl_pipeline API internally.
Currently this API is targeting Cogl 2.0 so we will have time to
integrate it properly with other upcoming Cogl 2.0 work.
The basic reasons for the rename are:
- That the term "material" implies to many people that they are
constrained to fragment processing; perhaps as some kind of high-level
texture abstraction.
- In Clutter they get exposed by ClutterTexture actors which may be
re-inforcing this misconception.
- When comparing how other frameworks use the term material, a material
sometimes describes a multi-pass fragment processing technique which
isn't the case in Cogl.
- In code, "CoglPipeline" will hopefully be a much more self documenting
summary of what these objects represent; a full GPU pipeline
configuration including, for example, vertex processing, fragment
processing and blending.
- When considering the API documentation story, at some point we need a
document introducing developers to how the "GPU pipeline" works so it
should become intuitive that CoglPipeline maps back to that
description of the GPU pipeline.
- This is consistent in terminology and concept to OpenGL 4's new
pipeline object which is a container for program objects.
Note: The cogl-material.[ch] files have been renamed to
cogl-material-compat.[ch] because otherwise git doesn't seem to treat
the change as a moving the old cogl-material.c->cogl-pipeline.c and so
we loose all our git-blame history.
This merges the two implementations of CoglProgram for the GLES2 and
GL backends into one. The implementation is more like the GLES2
version which would track the uniform values and delay sending them to
GL. CoglProgram is now effectively just a GList of CoglShaders along
with an array of stored uniform values. CoglProgram never actually
creates a GL program, instead this is left up to the GLSL material
backend. This is necessary on GLES2 where we may need to relink the
user's program with different generated shaders depending on the other
emulated fixed function state. It will also be necessary in the future
GLSL backends for regular OpenGL. The GLSL and ARBfp material backends
are now the ones that create and link the GL program from the list of
shaders. The linked program is attached to the private material state
so that it can be reused if the CoglProgram is used again with the
same material. This does mean the program will get relinked if the
shader is used with multiple materials. This will be particularly bad
if the legacy cogl_program_use function is used because that
effectively always makes one-shot materials. This problem will
hopefully be alleviated if we make a hash table with a cache of
generated programs. The cogl program would then need to become part of
the hash lookup.
Each CoglProgram now has an age counter which is incremented every
time a shader is added. This is used by the material backends to
detect when we need to create a new GL program for the user program.
The internal _cogl_use_program function now takes a GL program handle
rather than a CoglProgram. It no longer needs any special differences
for GLES2. The GLES2 wrapper function now also uses this function to
bind its generated shaders.
The ARBfp shaders no longer store a copy of the program source but
instead just directly create a program object when cogl_shader_source
is called. This avoids having to reupload the source if the same
shader is used in multiple materials.
There are currently a few gross hacks to get the GLES2 backend to work
with this. The problem is that the GLSL material backend is now
generating a complete GL program but the GLES2 wrapper still needs to
add its fixed function emulation shaders if the program doesn't
provide either a vertex or fragment shader. There is a new function in
the GLES2 wrapper called _cogl_gles2_use_program which replaces the
previous cogl_program_use implementation. It extracts the GL shaders
from the GL program object and creates a new GL program containing all
of the shaders plus its fixed function emulation. This new program is
returned to the GLSL material backend so that it can still flush the
custom uniforms using it. The user_program is attached to the GLES2
settings struct as before but its stored using a GL program handle
rather than a CoglProgram pointer. This hack will go away once the
GLSL material backend replaces the GLES2 wrapper by generating the
code itself.
Under Mesa this currently generates some GL errors when glClear is
called in test-cogl-shader-glsl. I think this is due to a bug in Mesa
however. When the user program on the material is changed the GLSL
backend gets notified and deletes the GL program that it linked from
the user shaders. The program will still be bound in GL
however. Leaving a deleted shader bound exposes a bug in Mesa's
glClear implementation. More details are here:
https://bugs.freedesktop.org/show_bug.cgi?id=31194
