Ideally we wouldn't have any private symbols exported, but for now there
are some APIs that coglpango needs access to that aren't public so we
have ensure they are exported. The aim is to get rid of this need at
some point.
When building on windows for example we need to ensure we pass
-no-undefined to the linker. Although we were substituting a
COGL_EXTRA_LDFLAGS variable from our configure.ac we forgot to
reference that when linking cogl.
Until Cogl gains native win32/OSX support this remove the osx and win32
winsys files and instead we'll just rely on the stub-winsys.c to handle
these platforms. Since the only thing the platform specific files were
providing anyway was a get_proc_address function; it was trivial to
simply update the clutter backend code to handle this directly for now.
The GDL API is used for example on intel ce4100 (aka Sodaville) based
systems as a way to allocate memory that can be composited using the
platforms overlay hardware. This updates the Cogl EGL winsys and the
support in Clutter so we can continue to support these platforms.
As was recently done for the GLX window system code, this commit moves
the EGL window system code down from the Clutter backend code into a
Cogl winsys.
Note: currently the cogl/configure.ac is hard coded to only build the GLX
winsys so currently this is only available when building Cogl as part
of Clutter.
The "DRM_SURFACELESS" EGL platform was invented when we were adding the
wayland backend to Clutter but in the end we added a dedicated backend
instead of extending the EGL backend so actually the platform name isn't
used.
Previously the mask of available winsys features was stored in a
CoglBitmask. That isn't the ideal type to use for this because it is
intended for a growable array of bits so it can allocate extra memory
if there are more than 31 flags set. For the winsys feature flags the
highest used bit is known at compile time so it makes sense to
allocate a fixed array instead. This is conceptually similar to the
CoglDebugFlags which are stored in an array of integers with macros to
test a bit in the array. This moves the macros used for CoglDebugFlags
to cogl-flags.h and makes them more generic so they can be shared with
CoglContext.
This backend hasn't been used for years now and so because it is
untested code and almost certainly doesn't work any more it would be a
burdon to continue trying to maintain it. Considering that we are now
looking at moving OpenGL window system integration code down from
Clutter backends into Cogl that will be easier if we don't have to
consider this backend.
This adds an autogen.sh, configure.ac and build/autotool files etc under
clutter/cogl and makes some corresponding Makefile.am changes that make
it possible to build and install Cogl as a standalone library.
Some notable things about this are:
A standalone installation of Cogl installs 3 pkg-config files;
cogl-1.0.pc, cogl-gl-1.0.pc and cogl-2.0.pc. The second is only for
compatibility with what clutter installed though I'm not sure that
anything uses it so maybe we could remove it. cogl-1.0.pc is what
Clutter would use if it were updated to build against a standalone cogl
library. cogl-2.0.pc is what you would use if you were writing a
standalone Cogl application.
A standalone installation results in two libraries currently, libcogl.so
and libcogl-pango.so. Notably we don't include a major number in the
sonames because libcogl supports two major API versions; 1.x as used by
Clutter and the experimental 2.x API for standalone applications.
Parallel installation of later versions e.g. 3.x and beyond will be
supportable either with new sonames or if we can maintain ABI then we'll
continue to share libcogl.so.
The headers are similarly not installed into a directory with a major
version number since the same headers are shared to export the 1.x and
2.x APIs (The only difference is that cogl-2.0.pc ensures that
-DCOGL_ENABLE_EXPERIMENTAL_2_0_API is used). Parallel installation of
later versions is not precluded though since we can either continue
sharing or later add a major version suffix.
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.
As part of the process of splitting Cogl out as a standalone graphics
API we need to introduce some API concepts that will allow us to
initialize a new CoglContext when Clutter isn't there to handle that for
us...
The new objects roughly in the order that they are (optionally) involved
in constructing a context are: CoglRenderer, CoglOnscreenTemplate,
CoglSwapChain and CoglDisplay.
Conceptually a CoglRenderer represents a means for rendering. Cogl
supports rendering via OpenGL or OpenGL ES 1/2.0 and those APIs are
accessed through a number of different windowing APIs such as GLX, EGL,
SDL or WGL and more. Potentially in the future Cogl could render using
D3D or even by using libdrm and directly banging the hardware. All these
choices are wrapped up in the configuration of a CoglRenderer.
Conceptually a CoglDisplay represents a display pipeline for a renderer.
Although Cogl doesn't aim to provide a detailed abstraction of display
hardware, on some platforms we can give control over multiple display
planes (On TV platforms for instance video content may be on one plane
and 3D would be on another so a CoglDisplay lets you select the plane
up-front.)
Another aspect of CoglDisplay is that it lets us negotiate a display
pipeline that best supports the type of CoglOnscreen framebuffers we are
planning to create. For instance if you want transparent CoglOnscreen
framebuffers then we have to be sure the display pipeline wont discard
the alpha component of your framebuffers. Or if you want to use
double/tripple buffering that requires support from the display
pipeline.
CoglOnscreenTemplate and CoglSwapChain are how we describe our default
CoglOnscreen framebuffer configuration which can affect the
configuration of the display pipeline.
The default/simple way we expect most CoglContexts to be constructed
will be via something like:
if (!cogl_context_new (NULL, &error))
g_error ("Failed to construct a CoglContext: %s", error->message);
Where that NULL is for an optional "display" parameter and NULL says to
Cogl "please just try to do something sensible".
If you want some more control though you can manually construct a
CoglDisplay something like:
display = cogl_display_new (NULL, NULL);
cogl_gdl_display_set_plane (display, plane);
if (!cogl_display_setup (display, &error))
g_error ("Failed to setup a CoglDisplay: %s", error->message);
And in a similar fashion to cogl_context_new() you can optionally pass
a NULL "renderer" and/or a NULL "onscreen template" so Cogl will try to
just do something sensible.
If you need to change the CoglOnscreen defaults you can provide a
template something like:
chain = cogl_swap_chain_new ();
cogl_swap_chain_set_has_alpha (chain, TRUE);
cogl_swap_chain_set_length (chain, 3);
onscreen_template = cogl_onscreen_template_new (chain);
cogl_onscreen_template_set_pixel_format (onscreen_template,
COGL_PIXEL_FORMAT_RGB565);
display = cogl_display_new (NULL, onscreen_template);
if (!cogl_display_setup (display, &error))
g_error ("Failed to setup a CoglDisplay: %s", error->message);
This tries to make the naming style of files under cogl/winsys/
consistent with other cogl source files. In particular private header
files didn't have a '-private' infix.
This gives us a way to clearly track the internal Cogl API that Clutter
depends on. The aim is to split Cogl out from Clutter into a standalone
3D graphics API and eventually we want to get rid of any private
interfaces for Clutter so its useful to have a handle on that task.
Actually it's not as bad as I was expecting though.
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.
This adds a new experimental function (you need to define
COGL_ENABLE_EXPERIMENTAL_API to access it) which takes us towards being
able to have a standalone Cogl API. This is really a minor aesthetic
change for now since all the GL context creation code still lives in
Clutter but it's a step forward none the less.
Since our current designs introduce a CoglDisplay object as something
that would be passed to the context constructor this provides a stub
cogl-display.h with CoglDisplay typedef.
_cogl_context_get_default() which Clutter uses to access the Cogl
context has been modified to use cogl_context_new() to initialize
the default context.
There is one rather nasty hack used in this patch which is that the
implementation of cogl_context_new() has to forcibly make the allocated
context become the default context because currently all the code in
Cogl assumes it can access the context using _COGL_GET_CONTEXT including
code used to initialize the context.
glib already has a data type to manage a list of callbacks called a
GHookList so we might as well use it instead of maintaining Cogl's own
type. The glib version may be slightly more efficient because it
avoids using a GList and instead encodes the prev and next pointers
directly in the GHook structure. It also has more features than
CoglCallbackList.
Instead of directly banging GL to migrate textures the atlas now uses
the CoglFramebuffer API. It will use one of four approaches; it can
set up two FBOs and use _cogl_blit_framebuffer to copy between them;
it can use a single target fbo and then render the source texture to
the FBO using a Cogl draw call; it can use a single FBO and call
glCopyTexSubImage2D; or it can fallback to reading all of the texture
data back to system memory and uploading it again with a sub texture
update.
Previously GL calls were used directly because Cogl wasn't able to
create a framebuffer without a stencil and depth buffer. However there
is now an internal version of cogl_offscreen_new_to_texture which
takes a set of flags to disable the two buffers.
The code for blitting has now been moved into a separate file called
cogl-blit.c because it has become quite long and it may be useful
outside of the atlas at some point.
The 4 different methods have a fixed order of preference which is:
* Texture render between two FBOs
* glBlitFramebuffer
* glCopyTexSubImage2D
* glGetTexImage + glTexSubImage2D
Once a method is succesfully used it is tried first for all subsequent
blits. The default default can be overridden by setting the
environment variable COGL_ATLAS_DEFAULT_BLIT_MODE to one of the
following values:
* texture-render
* framebuffer
* copy-tex-sub-image
* get-tex-data
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.
This adds a utility function that can determine if a given point
intersects an arbitrary polygon, by counting how many edges a
"semi-infinite" horizontal ray crosses from that point. The plan is to
use this for a software based read-pixel fast path that avoids using the
GPU to rasterize journaled primitives and can instead intersect a point
being read with quads in the journal to determine the correct color.
The GLES2 wrapper is no longer needed because the shader generation is
done within the GLSL fragend and vertend and any functions that are
different for GLES2 are now guarded by #ifdefs.
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.
The vertends are intended to flush state that would be represented in
a vertex program. Code to handle the layer matrix, lighting and
point size has now been moved from the common cogl-pipeline-opengl
backend to the fixed vertend.
'progend' is short for 'program backend'. The progend is intended to
operate on combined state from a fragment backend and a vertex
backend. The progend has an 'end' function which is run whenever the
pipeline is flushed and the two pipeline change notification
functions. All of the progends are run whenever the pipeline is
flushed instead of selecting a single one because it is possible that
multiple progends may be in use for example if the vertends and
fragends are different. The GLSL progend will take the shaders
generated by the fragend and vertend and link them into a single
program. The fragend code has been changed to only generate the shader
and not the program. The idea is that pipelines can share fragment
shader objects even if their vertex state is different. The authority
for the progend needs to be the combined authority on the vertend and
fragend state.
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.
To allow us to have gobject properties that accept a CoglMatrix value we
need to register a GType. This adds a cogl_gtype_matrix_get_type function
that will register a static boxed type called "CoglMatrix".
This adds a new section to the reference manual for GType integration
functions.
The GLES2 wrapper no longer needs to generate any fragment shader
state because the GLSL pipeline backend will always give the wrapper a
custom fragment shader. This simplifies a lot of the state comparison
done by the wrapper. The fog generation is also removed even though
it's actually part of the vertex shader because only the fixed
function pipeline backend actually calls the fog functions so it would
be disabled when using any of the other backends anyway. We can fix
this when the two shader backends also start generating vertex
shaders.
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.
Flushing the clip state no longer does anything that would cause the
journal to flush. The clip state is only flushed when flushing the
framebuffer state and in all cases this ends up flushing the journal
in one way or another anyway. Avoiding flushing the journal will make
it easier to log the clip state in the journal.
Previously when trying to set up a rectangle clip that can't be
scissored or when using a path clip the code would use cogl_rectangle
as part of the process to fill the stencil buffer. This is now changed
to use a new internal _cogl_rectangle_immediate function which
directly uses the vertex array API to draw a triangle strip without
affecting the journal. This should be just as efficient as the
previous journalled code because these places would end up flushing
the journal immediately before and after submitting the single
rectangle anyway and flushing the journal always creates a new vbo so
it would effectively do the same thing.
Similarly there is also a new internal _cogl_clear function that does
not flush the journal.
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.
A CoglPrimitive is a retainable object for drawing a single primitive,
such as a triangle strip, fan or list.
CoglPrimitives build on CoglVertexAttributes and CoglIndices which
themselves build on CoglVertexArrays and CoglIndexArrays respectively.
A CoglPrimitive encapsulates enough information such that it can be
retained in a queue (e.g. the Cogl Journal, or renderlists in the
future) and drawn at some later time.
A CoglVertexAttribute defines a single attribute contained in a
CoglVertexArray. I.e. a CoglVertexArray is simply a buffer of N bytes
intended for containing a collection of attributes (position, color,
normals etc) and a CoglVertexAttribute defines one such attribute by
specifying its start offset in the array, its type, the number of
components and the stride etc.
CoglIndices define a range of indices inside a CoglIndexArray. I.e. a
CoglIndexArray is simply a buffer of N bytes and you can then
instantiate multiple CoglIndices collections that define a sub-region of
a CoglIndexArray by specifying a start offset and an index data type.
This adds a new CoglVertexArray object which is a subclass of CoglBuffer
used to hold vertex attributes. A later commit will add a
CoglVertexAttribute API which will be used to describe the attributes
inside a CoglVertexArray.
A CoglIndexArray is a subclass of CoglBuffer and will be used to hold
vertex indices. A later commit will add a CoglIndices API which will
allow describing a range of indices inside a CoglIndexArray.
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
*** WARNING: THIS COMMIT CHANGES THE BUILD ***
Do not recurse into the backend directories to build private, internal
libraries.
We only recurse from clutter/ into the cogl sub-directory; from there,
we don't recurse any further. All the backend-specific code in Cogl and
Clutter is compiled conditionally depending on the macros defined by the
configure script.
We still recurse from the top-level directory into doc, clutter and
tests, because gtk-doc and tests do not deal nicely with non-recursive
layouts.
This change makes Clutter compile slightly faster, and cleans up the
build system, especially when dealing with introspection data.
Ideally, we also want to make Cogl part of the top-level build, so that
we can finally drop the sed trick to change the shared library from the
GIR before compiling it.
Currently disabled:
‣ OSX backend
‣ Fruity backend
Currently enabled but untested:
‣ EGL backend
‣ Windows backend
Let's try to keep Cogl's build as non-recursive as possible, in the hope
that one day we'll be able to make it fully non-recursive along with the
rest of Clutter.
