Weak materials are ones that don't take a reference on their parent and
they are associated with a callback that notifies when the material is
destroyed, because its parent was freed or modified.
More details can be found at:
http://wiki.clutter-project.org/wiki/CoglDesign/CoglMaterial
For now the concept is internal only but the plan is to make this public
at some point once we have tested the design internally.
Textures within a layer were compared for equality by comparing their
texture handle. However this means that sub textures and atlas
textures which may be internally using the same GL handle would not be
batched together. Instead it now tries to determine the underlying GL
handle using either the slice override or _cogl_texture_get_gl_texture
and then compares those.
Previously we had an internal only _cogl_material_set_user_program to
redirect legacy usage of cogl_program_use() through CoglMaterial. This
instead makes the API public because until we implement our planned
"snippet" framework we need a stop-gap solution for using shaders in
Cogl.
The plan is to also support ARBfp with the cogl_program/shader API so
this API will also allow clutter-gst to stop using direct OpenGL calls
that conflict with Cogl's state tracking.
A change to a layer is also going to be a change to its owning material
so we have to chain up in _cogl_material_layer_pre_change_notify and
call _cogl_material_pre_change_notify. Previously we were only
considering if the owning material was referenced in the journal but
that ignores that it might also have dependants. We no longer need to
flush the journal directly in layer_pre_change_notify.
In _cogl_material_layer_pre_change_notify when we see that a layer has
dependants and it can't be modified directly then we allocate a new
layer. In this case we also have to link the new layer to its required
owner. If the immutable layer we copied had the same owner though we
weren't unlinking that old layer.
In _cogl_material_pre_change_notify we need to identify if it's a sparse
property being changed and if so initialize the state group if the given
material isn't currently the authority for it.
Previously we were unconditionally calling
_cogl_material_initialize_state which would e.g. NULL the layer
differences list of a material each time a layer change was notified.
It would also call _cogl_material_initialize_state for non-sparse
properties which should always be valid at this point so the function
has been renamed to _cogl_material_initialize_sparse_state to make this
clearer with a corresponding g_return_if_fail check.
This fixes how we copy layer differences in
_cogl_material_copy_layer_differences.
We were making a redundant g_list_copy of the src differences and then
iterating the src list calling _cogl_material_add_layer_difference for
each entry which would double the list length, but the initial copy
directly referenced the original layers which wasn't correct.
Also we were initializing dest->n_layers before copying the layer
differences but the act of copying the differences will re-initialize
n_layers to 0 when adding the first layer_difference since it will
trigger a layer_pre_change_notify and since the dest material isn't yet
a STATE_LAYERS authority the state group is initialized before allowing
the change.
This improve the dot file output available when calling
_cogl_debug_dump_materials_dot_file. The material graph now directly
points into the layer graph and the layers now show the texture unit
index.
When the texture is set on a layer so that it is back to the parent's
texture it would clear the texture change flag but it wouldn't unref
the texture. The free function for a material layer does not unref the
texture if the change flag is cleared so the texture would end up
leaking. This happens for ClutterTexture because it disposes the
texture by setting layer 0 of the material to COGL_INVALID_HANDLE
which ends up the same as the default material.
In _cogl_material_layer_pre_paint we were mistakenly dereferencing the
layer->texture member for the passed layer instead of dereferencing the
texture state authority which was causing crashes in some cases.
In OpenGL the 'shininess' lighting parameter is floating point value
limited to the range 0.0→128.0. This number is used to affect the size
of the specular highlight. Cogl materials used to only accept a number
between 0.0 and 1.0 which then gets multiplied by 128.0 before sending
to GL. I think the assumption was that this is just a weird GL quirk
so we don't expose it. However the value is used as an exponent to
raise the attenuation to a power so there is no conceptual limit to
the value.
This removes the mapping and changes some of the documentation.
http://bugzilla.clutter-project.org/show_bug.cgi?id=2222
This moves the code supporting _cogl_material_flush_gl_state into
cogl-material-opengl.c as part of an effort to reduce the size of
cogl-material.c to keep it manageable.
In general cogl-material.c has become far to large to manage in one
source file. As one of the ways to try and break it down this patch
starts to move some of lower level texture unit state management out
into cogl-material-opengl.c. The naming is such because the plan is to
follow up and migrate the very GL specific state flushing code into the
same file.
When the support for redirecting the legacy fog state through cogl
material was added in 9b9e764dc, the code to handle copying the fog
state in _cogl_material_copy_differences was missed.
Using 'r' to name the third component is problematic because that is
commonly used to represent the red component of a vector representing
a color. Under GLSL this is awkward because the texture swizzling for
a vector uses a single letter for each component and the names for
colors, textures and positions are synonymous. GLSL works around this
by naming the components of the texture s, t, p and q. Cogl already
effectively already exposes this naming because it exposes GLSL so it
makes sense to use that naming consistently. Another alternative could
be u, v and w. This is what Blender and Direct3D use. However the w
component conflicts with the w component of a position vertex.
We can use this error in more unsupported situations than just when we
have a Cogl feature flag for the error. For example if a non-sliced
texture is created with dimensions that are too large then we could
throw this error. Therefore it seems good to rename to something more
general.
This adds a COGL_OBJECT_INTERNAL_DEFINE macro and friends that are the
same as COGL_OBJECT_DEFINE except that they prefix the cogl_is_*
function with an underscore so that it doesn't get exported in the
shared library.
Previously COGL_OBJECT_DEFINE would always define deprecated
cogl_$type_{ref,unref} functions even if the type is new or if the
type is entirely internal. An application would still find it
difficult to use these because they wouldn't be in the headers, but it
still looks bad that they are exported from the shared library. This
patch changes it so that the deprecated ref counting functions are
defined using a separate macro and only the types that have these
functions in the headers call this macro.
Since 365605cf42, materials and layers are represented in a tree
structure that allows traversing up through parents and iterating down
through children. This re-works the related typedefs and reparenting
code so that they can be shared.
There were a few problems flushing texture overrides so that sliced
textures would not work:
* In _cogl_material_set_layer_texture it ignored the 'overriden'
parameter and always set texture_overridden to FALSE.
* cogl_texture_get_gl_texture wasn't being called correctly in
override_layer_texture_cb. It returns a gboolean to indicate the
error status but this boolean was being assigned to gl_target.
* _cogl_material_layer_texture_equal did not take into account the
override.
* _cogl_material_layer_get_texture_info did not return the overridden
texture so it would always use the first texture slice.
This adds a new API call to enable point sprite coordinate generation
for a material layer:
void
cogl_material_set_layer_point_sprite_coords_enabled (CoglHandle material,
int layer_index,
gboolean enable);
There is also a corresponding get function.
Enabling point sprite coords simply sets the GL_COORD_REPLACE of the
GL_POINT_SPRITE glTexEnv when flusing the material. There is no
separate application control for glEnable(GL_POINT_SPRITE). Instead it
is left permanently enabled under the assumption that it has no affect
unless GL_COORD_REPLACE is enabled for a texture unit.
http://bugzilla.openedhand.com/show_bug.cgi?id=2047
Recently I added a _cogl_debug_dump_materials_dot_file function for
debugging the sparse material state. This extends the state dumped to
include the graph of layer state also.
We were mistakenly only initializing layer->layer_index for new layers
associated with texture units > 0. This had gone unnoticed because
normally layers associated with texture unit0 have a layer index of 0
too. Mutter was hitting this issue because it was initializing layer 1
before layer 0 for one of its materials so layer 1 was temporarily
associated with texture unit 0.
Previously cogl_set_fog would cause a flush of the Cogl journal and
would directly bang the GL state machine to setup fogging. As part of
the ongoing effort to track most state in CoglMaterial to support
renderlists this now adds an indirection so that cogl_set_fog now just
updates ctx->legacy_fog_state. The fogging state then gets enabled as a
legacy override similar to how the old depth testing API is handled.
This adds a _cogl_debug_dump_materials_dot_file function that can be
used to dump all the descendants of the default material to a file using
the dot format which can then be converted to an image to visualize.
In _cogl_material_pre_change_notify if a material with descendants is
modified then we create a new material that is a copy of the one being
modified and reparent those descendants to the new material.
This patch ensures we drop the reference we get from cogl_material_copy
since we can rely on the descendants to keep the new material alive.
cogl_material_copy was taking a reference on the original texture when
making a copy. However it then calls _cogl_material_set_parent on the
material which also takes a reference on the parent. The second
reference is cleaned up whenever _cogl_material_unparent is called and
this is also called by _cogl_material_free. However, it seems that
nothing was cleaning up the first reference. I think the reference is
entirely unnecessary so this patch removes it.
As part of the ongoing effort to remove CoglHandle from the API this
switches the cogl_material API to use a strongly typed CoglMaterial
pointer instead of CoglHandle.
This splits the fragment processing backends (glsl, arbfp and fixed) out
from cogl-material.c into their own cogl-material-{glsl,arbfp,fixed}.c
files in an effort to help and keep cogl-material.c maintainable.
Some of the arguments to the material and path functions were taking a
pointer to a CoglColor or an array of floats that was not intended to
be written to but were not marked with const.
in _cogl_material_prune_empty_layer_difference we sometimes unref the
given layer before dereferencing it to get a pointer to its parent. This
defers the unref until after we have fetched the parent pointer.
Instead of the ensure_mipmaps virtual that is only called whenever the
texture is about to be rendered with a min filter that needs the
mipmap, there is now a pre_paint virtual that is always called when
the texture is about to be painted in any way. It has a flags
parameter which is used to specify whether the mipmap will be needed.
This is useful for CoglTexturePixmapX11 because it needs to do stuff
before painting that is unrelated to mipmapping.
The function had a line like:
CoglMaterial *material =
material = _cogl_material_pointer_from_handle (material_handle);
where the duplicate "material =" wasn't intended, so this patch removes
it.
The window headers contain the line
#define near
so it's not possible to use the symbol 'near' in code that's portable
to Windows. This replaces it with 'near_val'.
I think the define is meant to improve compatibility with code written
for Windows 3.1 where near would be a keyword to make it a smaller
pointer size.
We don't need to generate a new ARBfp program for every material created
if we can find an ancestor whos state will result in the same program
being generated.
The more code we can have adopt the coding pattern of deriving their
materials from other similar materials using cogl_material_copy() the
more likely this metric will be good enough on its own to minimize the
set of arbfp programs necessary to support a given application.
Previously in _cogl_material_pre_change_notify we manually freed the
layer caches of a material if we caused a reparent, but it makes more
sense to have _cogl_material_set_parent do this directly instead.
This adds a _cogl_material_weak_copy() function that can be used to
create materials that don't count as strong dependants on their parents.
This means the parent can be modified without worrying about how it will
affect weak materials. The material age of the parent can potentially be
queried to determine if a weak material might need to be re-created.
When we add support for weak materials it's expected that Clutter will
want to attach them as private data to other materials and it needs a
mechanism to determine when a weak material should be re-created because
its parent has changed somehow.
This adds the concept of a material age (internal only currently) which
increments whenever a material is modified. Clutter can then save the
age of the material which its weak materials are derived from and later
determine when the weak material may be invalid.
In _cogl_material_equal we were repeating the same code pattern to
compare several of the state groups so this just adds
simple_property_equal function that's now used instead.
This redirects the legacy depth testing APIs through CoglMaterial and
adds a new experimental cogl_material_ API for handling the depth
testing state.
This adds the following new functions:
cogl_material_set_depth_test_enabled
cogl_material_get_depth_test_enabled
cogl_material_set_depth_writing_enabled
cogl_material_get_depth_writing_enabled
cogl_material_set_depth_test_function
cogl_material_get_depth_test_function
cogl_material_set_depth_range
cogl_material_get_depth_range
As with other experimental Cogl API you need to define
COGL_ENABLE_EXPERIMENTAL_API to access them and their stability isn't
yet guaranteed.
Since it can sometimes be awkward to figure out where a particular
material came from when debugging, this adds a breadcrumb mechanism that
lets you associate a const string with a material that may give a clue
about its origin.
As a follow on to using cogl_material_copy instead of flush options this
patch now removes the ability to pass flush options to
_cogl_material_equal which is the final reference to the
CoglMaterialFlushOptions mechanism.
Since cogl_material_copy should now be cheap to use we can simplify
how we handle fallbacks and wrap mode overrides etc by simply copying
the original material and making our override changes on the new
material. This avoids the need for a sideband state structure that has
been growing in size and makes flushing material state more complex.
Note the plan is to eventually use weak materials for these override
materials and attach these as private data to the original materials so
we aren't making so many one-shot materials.
This is a complete overhaul of the data structures used to manage
CoglMaterial state.
We have these requirements that were aiming to meet:
(Note: the references to "renderlists" correspond to the effort to
support scenegraph level shuffling of Clutter actor primitives so we can
minimize GPU state changes)
Sparse State:
We wanted a design that allows sparse descriptions of state so it scales
well as we make CoglMaterial responsible for more and more state. It
needs to scale well in terms of memory usage and the cost of operations
we need to apply to materials such as comparing, copying and flushing
their state. I.e. we would rather have these things scale by the number
of real changes a material represents not by how much overall state
CoglMaterial becomes responsible for.
Cheap Copies:
As we add support for renderlists in Clutter we will need to be able to
get an immutable handle for a given material's current state so that we
can retain a record of a primitive with its associated material without
worrying that changes to the original material will invalidate that
record.
No more flush override options:
We want to get rid of the flush overrides mechanism we currently use to
deal with texture fallbacks, wrap mode changes and to handle the use of
highlevel CoglTextures that need to be resolved into lowlevel textures
before flushing the material state.
The flush options structure has been expanding in size and the structure
is logged with every journal entry so it is not an approach that scales
well at all. It also makes flushing material state that much more
complex.
Weak Materials:
Again for renderlists we need a way to create materials derived from
other materials but without the strict requirement that modifications to
the original material wont affect the derived ("weak") material. The
only requirement is that its possible to later check if the original
material has been changed.
A summary of the new design:
A CoglMaterial now basically represents a diff against its parent.
Each material has a single parent and a mask of state that it changes.
Each group of state (such as the blending state) has an "authority"
which is found by walking up from a given material through its ancestors
checking the difference mask until a match for that group is found.
There is only one root node to the graph of all materials, which is the
default material first created when Cogl is being initialized.
All the groups of state are divided into two types, such that
infrequently changed state belongs in a separate "BigState" structure
that is only allocated and attached to a material when necessary.
CoglMaterialLayers are another sparse structure. Like CoglMaterials they
represent a diff against their parent and all the layers are part of
another graph with the "default_layer_0" layer being the root node that
Cogl creates during initialization.
Copying a material is now basically just a case of slice allocating a
CoglMaterial, setting the parent to be the source being copied and
zeroing the mask of changes.
Flush overrides should now be handled by simply relying on the cheapness
of copying a material and making changes to it. (This will be done in a
follow on commit)
Weak material support will be added in a follow on commit.
