Since we've had several developers from admirable projects say they
would like to use Cogl but would really prefer not to pull in
gobject,gmodule and glib as extra dependencies we are investigating if
we can get to the point where glib is only an optional dependency.
Actually we feel like we only make minimal use of glib anyway, so it may
well be quite straightforward to achieve this.
This adds a --disable-glib configure option that can be used to disable
features that depend on glib.
Actually --disable-glib doesn't strictly disable glib at this point
because it's more helpful if cogl continues to build as we make
incremental progress towards this.
The first use of glib that this patch tackles is the use of
g_return_val_if_fail and g_return_if_fail which have been replaced with
equivalent _COGL_RETURN_VAL_IF_FAIL and _COGL_RETURN_IF_FAIL macros.
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>
The code that adds the silhouette of a path to the stencil buffer was
living in cogl2-path.c which seemed out of place when the bulk of the
work really related more to how the stencil buffer is managed and
basically only one line (a call to _cogl_path_fill_nodes) really related
to the path code directly.
This moves the code into cogl-clip-stack.c alone with similar code
that can add rectangle masks to the stencil buffer.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
If we are asked to fill a path using any sliced textures then we need
to fallback to adding a mask of the path to the stencil buffer
and then drawing a bounding rectangle with the source textures instead.
Previously we were sharing some of the clip-stack code for adding
the path mask to the stencil buffer and being careful to check
that the current clip stack has been flushed already. We then made
sure to dirty the clip stack to be sure the path mask would be cleared
from the stencil buffer later.
This patch aims to simplify how this fallback is dealt with by just
using the public clipping API instead of relying on more fiddly tricks
to modify the stencil buffer directly without conflicting with the clip
stack.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
As part of the on going, incremental effort to purge the non type safe
CoglHandle type from the Cogl API this patch tackles most of the
CoglHandle uses relating to textures.
We'd postponed making this change for quite a while because we wanted to
have a clearer understanding of how we wanted to evolve the texture APIs
towards Cogl 2.0 before exposing type safety here which would be
difficult to change later since it would imply breaking APIs.
The basic idea that we are steering towards now is that CoglTexture
can be considered to be the most primitive interface we have for any
object representing a texture. The texture interface would provide
roughly these methods:
cogl_texture_get_width
cogl_texture_get_height
cogl_texture_can_repeat
cogl_texture_can_mipmap
cogl_texture_generate_mipmap;
cogl_texture_get_format
cogl_texture_set_region
cogl_texture_get_region
Besides the texture interface we will then start to expose types
corresponding to specific texture types: CoglTexture2D,
CoglTexture3D, CoglTexture2DSliced, CoglSubTexture, CoglAtlasTexture and
CoglTexturePixmapX11.
We will then also expose an interface for the high-level texture types
we have (such as CoglTexture2DSlice, CoglSubTexture and
CoglAtlasTexture) called CoglMetaTexture. CoglMetaTexture is an
additional interface that lets you iterate a virtual region of a meta
texture and get mappings of primitive textures to sub-regions of that
virtual region. Internally we already have this kind of abstraction for
dealing with sliced texture, sub-textures and atlas textures in a
consistent way, so this will just make that abstraction public. The aim
here is to clarify that there is a difference between primitive textures
(CoglTexture2D/3D) and some of the other high-level textures, and also
enable developers to implement primitives that can support meta textures
since they can only be used with the cogl_rectangle API currently.
The thing that's not so clean-cut with this are the texture constructors
we have currently; such as cogl_texture_new_from_file which no longer
make sense when CoglTexture is considered to be an interface. These
will basically just become convenient factory functions and it's just a
bit unusual that they are within the cogl_texture namespace. It's worth
noting here that all the texture type APIs will also have their own type
specific constructors so these functions will only be used for the
convenience of being able to create a texture without really wanting to
know the details of what type of texture you need. Longer term for 2.0
we may come up with replacement names for these factory functions or the
other thing we are considering is designing some asynchronous factory
functions instead since it's so often detrimental to application
performance to be blocked waiting for a texture to be uploaded to the
GPU.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
Some code in Cogl such as when flushing a stencil clip assumes that it
can push a temporary simple pipeline to reset to a known state for
internal drawing operations. However this breaks down if the
application has set any legacy state because that is set globally so
it will also get applied to the internal pipeline.
_cogl_draw_attributes already had an internal flag to disable applying
the legacy state but I think this is quite awkward to use because not
all places that push a pipeline draw the attribute buffers directly so
it is difficult to pass the flag down through the layers.
Conceptually the legacy state is meant to be like a layer on top of
the purely pipeline-based state API so I think ideally we should have
an internal function to push the source without the applying the
legacy state. The legacy state can't be applied as the pipeline is
pushed because the global state can be modified even after it is
pushed. This patch adds a _cogl_push_source() function which takes an
extra boolean flag to mark whether to enable the legacy state. The
value of this flag is stored alongside the pipeline in the pipeline
stack. Another new internal function called
_cogl_get_enable_legacy_state queries whether the top entry in the
pipeline stack has legacy state enabled. cogl-primitives and the
vertex array drawing code now use this to determine whether to apply
the legacy state when drawing. The COGL_DRAW_SKIP_LEGACY_STATE flag is
now removed.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
Since 12b3d21aaa cogl is using the vertex attribute API to stroke a
path. However it was still manually appllying the legacy state to the
pipeline. cogl_vdraw_attributes also applies the legacy state so it
ends up getting applied twice. This patch just removes it from
_cogl_path_stroke_nodes.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
Commit 12b3d21a changed cogl-path so that it will use the vertex
attribute API to stroke the path in a similar way to how it was using
the API to fill the path. However it wasn't clearing the stroke buffer
when the path is modified so it would continue to use the unmodified
stroke.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
Some of the functions we were calling in cogl_framebuffer_clear[4f] were
referring to the current framebuffer, which would result in a crash
if nothing had been pushed before trying to explicitly clear a given
framebuffer.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
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.
For the first iteration of the CoglAttribute API several of the new
functions accepted a pointer to a NULL terminated list of CoglAttribute
pointers - probably as a way to reduce the number of arguments required.
This style isn't consistent with existing Cogl APIs though and so we now
explicitly pass n_attributes arguments and don't require the NULL
termination.
This is part of a broader cleanup of some of the experimental Cogl API.
One of the reasons for this particular rename is to switch away from
using the term "Array" which implies a regular, indexable layout which
isn't the case. We also want to have a strongly implied relationship
between CoglAttributes and CoglAttributeBuffers.
This renames the two internal functions _cogl_get_draw/read_buffer
as cogl_get_draw_framebuffer and _cogl_get_read_framebuffer. The
former is now also exposed as experimental API.
Drawing and clipping to paths is generally quite expensive because the
geometry has to be tessellated into triangles in a single VBO which
breaks up the journal batching. If we can detect when the path
contains just a single rectangle then we can instead divert to calling
cogl_rectangle which will take advantage of the journal, or by pushing
a rectangle clip which usually ends up just using the scissor.
This patch adds a boolean to each path to mark when it is a
rectangle. It gets cleared whenever a node is added or gets set to
TRUE whenever cogl2_path_rectangle is called. This doesn't try to
catch cases where a rectangle is composed by cogl_path_line_to and
cogl_path_move_to commands.
The current framebuffer is now internally separated so that there can
be a different draw and read buffer. This is required to use the
GL_EXT_framebuffer_blit extension. The current draw and read buffers
are stored as a pair in a single stack so that pushing the draw and
read buffer is done simultaneously with the new
_cogl_push_framebuffers internal function. Calling
cogl_pop_framebuffer will restore both the draw and read buffer to the
previous state. The public cogl_push_framebuffer function is layered
on top of the new function so that it just pushes the same buffer for
both drawing and reading.
When flushing the framebuffer state, the cogl_framebuffer_flush_state
function now tackes a pointer to both the draw and the read
buffer. Anywhere that was just flushing the state for the current
framebuffer with _cogl_get_framebuffer now needs to call both
_cogl_get_draw_buffer and _cogl_get_read_buffer.
This is part of a broader cleanup of some of the experimental Cogl API.
One of the reasons for this particular rename is to reduce the verbosity
of using the API. Another reason is that CoglVertexArray is going to be
renamed CoglAttributeBuffer and we want to help emphasize the
relationship between CoglAttributes and CoglAttributeBuffers.
Instead of having a single journal per context, we now have a
CoglJournal object for each CoglFramebuffer. This means we now don't
have to flush the journal when switching/pushing/popping between
different framebuffers so for example a Clutter scene that involves some
ClutterEffect actors that transiently redirect to an FBO can still be
batched.
This also allows us to track state in the journal that relates to the
current frame of its associated framebuffer which we'll need for our
optimization for using the CPU to handle reading a single pixel back
from a framebuffer when we know the whole scene is currently comprised
of simple rectangles in a journal.
This moves the implementation of cogl_clear into cogl-framebuffer.c as
two new internal functions _cogl_framebuffer_clear and
_cogl_framebuffer_clear4f. It's not clear if this is what the API will
look like as we make more of the CoglFramebuffer API public due to the
limitations of using flags to identify buffers when framebuffers may
contain any number of ancillary buffers but conceptually it makes some
sense to tie the operation of clearing a color buffer to a framebuffer.
The short term intention is to enable tracking the current clear color
as a property of the framebuffer as part of an optimization for reading
back single pixels when the geometry is simple enough that we can
compute the result quickly on the CPU. (If the point doesn't intersect
any geometry we'll need to return the last clear color.)
In the journal code and when generating the stroke path the vertices
are generated on the fly and stored in a CoglBuffer using
cogl_buffer_map. However cogl_buffer_map is allowed to fail but it
wasn't checking for a NULL return value. In particular on GLES it will
always fail because glMapBuffer is only provided by an extension. This
adds a new pair of internal functions called
_cogl_buffer_{un,}map_for_fill_or_fallback which wrap
cogl_buffer_map. If the map fails then it will instead return a
pointer into a GByteArray attached to the context. When the buffer is
unmapped the array is copied into the buffer using
cogl_buffer_set_data.
There is an internal version of cogl_draw_vertex_attributes_array
which previously just bypassed the framebuffer flushing, journal
flushing and pipeline validation so that it could be used to draw the
journal. This patch generalises the function so that it takes a set of
flags to specify which parts to flush. The public version of the
function now just calls the internal version with the flags set to
0. The '_real' version of the function has now been merged into the
internal version of the function because it was only called in one
place. This simplifies the code somewhat. The common code which
flushed the various state has been moved to a separate function. The
indexed versions of the functions have had a similar treatment.
http://bugzilla.clutter-project.org/show_bug.cgi?id=2481
All of the drawing needed in _cogl_add_path_to_stencil_buffer is done
with the vertex attribute API so there should be no need to flush the
enable flags to enable the vertex array. This was causing problems on
GLES2 where the vertex array isn't available.
Previously when stroking a path it was flushing a pipeline and then
directly calling glDrawArrays to draw the line strip from the path
nodes array. This patch changes it to build a CoglVertexArray and a
series of attributes to paint with instead. The vertex array and
attributes are attached to the CoglPath so it can be reused later. The
old vertex array for filling has been renamed to fill_vbo.
This reverts commit 4cfe90bde2.
GLSL 1.00 on GLES doesn't support unsized arrays so the whole idea
can't work.
Conflicts:
clutter/cogl/cogl/cogl-pipeline-glsl.c
Under GLES2 we were defining the cogl_tex_coord_in varying as an array
with a size determined by the number of texture coordinate arrays
enabled whenever the program is used. This meant that we may have to
regenerate the shader with a different size if the shader is used with
more texture coord arrays later. However in OpenGL the equivalent
builtin varying gl_TexCoord is simply defined as:
varying vec4 gl_TexCoord[]; /* <-- no size */
GLSL is documented that if you declare an array with no size then you
can only access it with a constant index and the size of the array
will be determined by the highest index used. If you want to access it
with a non-constant expression you need to redeclare the array
yourself with a size.
We can replicate the same behaviour in our Cogl shaders by instead
declaring the cogl_tex_coord_in with no size. That way we don't have
to pass around the number of tex coord attributes enabled when we
flush a material. It also means that CoglShader can go back to
directly uploading the source string to GL when cogl_shader_source is
called so that we don't have to keep a copy of it around.
If the user wants to access cogl_tex_coord_in with a non-constant
index then they can simply redeclare the array themself. Hopefully
developers will expect to have to do this if they are accustomed to
the gl_TexCoord array.
This adds an optional data argument for cogl_vertex_array_new() since it
seems that mostly every case where we use this API we follow up with a
cogl_buffer_set_data() matching the size of the new array. This
simplifies all those cases and whenever we want to delay uploading of
data then NULL can simply be passed.
When COGL_ENABLE_EXPERIMENTAL_2_0_API is defined cogl.h will now include
cogl2-path.h which changes cogl_path_new() so it can directly return a
CoglPath pointer; it no longer exposes a prototype for
cogl_{get,set}_path and all the remaining cogl_path_ functions now take
an explicit path as their first argument.
The idea is that we want to encourage developers to retain path objects
for as long as possible so they can take advantage of us uploading the
path geometry to the GPU. Currently although it is possible to start a
new path and query the current path, it is not convenient.
The other thing is that we want to get Cogl to the point where nothing
depends on a global, current context variable. This will allow us to one
day define a sensible threading model if/when that is ever desired.
