The transform_point function takes a modelview matrix, projection
matrix and a viewport and performs all three transformations on a
point to give a Cogl window coordinate. This is useful in a number of
places in Cogl so this patch moves it to cogl.c and adds it to
cogl-internal.h
As part of an effort to improve the architecture of CoglMaterial
internally this overhauls how we flush layer state to OpenGL by adding a
formal backend abstraction for fragment processing and further
formalizing the CoglTextureUnit abstraction.
There are three backends: "glsl", "arbfp" and "fixed". The fixed backend
uses the OpenGL fixed function APIs to setup the fragment processing,
the arbfp backend uses code generation to handle fragment processing
using an ARBfp program, and the GLSL backend is currently only there as
a formality to handle user programs associated with a material. (i.e.
the glsl backend doesn't yet support code generation)
The GLSL backend has highest precedence, then arbfp and finally the
fixed. If a backend can't support some particular CoglMaterial feature
then it will fallback to the next backend.
This adds three new COGL_DEBUG options:
* "disable-texturing" as expected should disable all texturing
* "disable-arbfp" always make the arbfp backend fallback
* "disable-glsl" always make the glsl backend fallback
* "show-source" show code generated by the arbfp/glsl backends
The Cogl context has now a feature_flags_private enum that will allow us
to query and use OpenGL features without exposing them in the public
API.
The ARB_fragment_program extension is the first user of those flags.
Looking for this extension only happens in the gl driver as the gles
drivers will not expose them.
One can use _cogl_features_available_private() to check for the
availability of such private features.
While at it, reindent cogl-internal.h as described in CODING_STYLE.
When _cogl_disable_other_texcoord_arrays is called it disables the
neccessary texcoord arrays and then removes the bits for the disabled
arrays in ctx->texcoord_arrays_enabled. However none of the places
that call the function then set any bits in ctx->texcoord_arrays_enabled
so the arrays would never get marked and they would never get disabled
again.
This patch just changes it so that _cogl_disable_other_texcoord_arrays
also sets the corresponding bits in ctx->texcoord_arrays_enabled.
Instead of directly using a guint32 to store a bitmask for each used
texcoord array, it now stores them in a CoglBitmask. This removes the
limitation of 32 layers (although there are still other places in Cogl
that imply this restriction). To disable texcoord arrays code should
call _cogl_disable_other_texcoord_arrays which takes a bitmask of
texcoord arrays that should not be disabled. There are two extra
bitmasks stored in the CoglContext which are used temporarily for this
function to avoid allocating a new bitmask each time.
http://bugzilla.openedhand.com/show_bug.cgi?id=2132
It should be quite acceptable to use a texture without defining any
texture coords. For example a shader may be in use that is doing
texture lookups without referencing the texture coordinates. Also it
should be possible to replace the vertex colors using a texture layer
without a texture but with a constant layer color.
enable_state_for_drawing_buffer no longer sets any disabled layers in
the overrides. Instead of counting the number of units with texture
coordinates it now keeps them in a mask. This means there can now be
gaps in the list of enabled texture coordinate arrays. To cope with
this, the Cogl context now also stores a mask to track the enabled
arrays. Instead of code manually iterating each enabled array to
disable them, there is now an internal function called
_cogl_disable_texcoord_arrays which disables a given mask.
I think this could also fix potential bugs when a vertex buffer has
gaps in the texture coordinate attributes that it provides. For
example if the vertex buffer only had texture coordinates for layer 2
then the disabling code would not disable the coordinates for layers 0
and 1 even though they are not used. This could cause a crash if the
previous data for those arrays is no longer valid.
http://bugzilla.openedhand.com/show_bug.cgi?id=2132
This stubs out an xlib event handling mechanism for Cogl. The intention
is for Clutter to use this to forward all x11 events to Cogl. As we move
winsys functionality down into Cogl, Cogl will become responsible for
handling a number of X events: ConfigureNotify events for onscreen
framebuffers, swap events and Damage events for cogl_x11_texture_pixmap.
This adds three new API calls:
CoglHandle cogl_path_get()
void cogl_path_set(CoglHandle path)
CoglHandle cogl_path_copy(CoglHandle path)
All of the fields relating to the path have been moved from the Cogl
context to a new CoglPath handle type. The cogl context now just
contains a CoglPath handle. All of the existing path commands
manipulate the data in the current path handle. cogl_path_new now just
creates a new path handle and unrefs the old one.
The path handle can be stored for later with cogl_path_get. The path
can then be copied with cogl_path_copy. Internally it implements
copy-on-write semantics with an extra optimisation that it will only
copy the data if the new path is modified, but not if the original
path is modified. It can do this because the only way to modify a path
is by appending to it so the copied path is able to store its own path
length and only render the nodes up to that length. For this to work
the copied path also needs to keep its own copies of the path extents
because the parent path may change these by adding nodes.
The clip stack now uses the cogl_path_copy mechanism to store paths in
the stack instead of directly copying the data. This should save some
memory and processing time.
Every now and then someone sees the cogl_enable API and gets confused,
thinking its public API so this renames the symbol to be clear that it's
is an internal only API.
Since using addresses that might change is something that finally
the FSF acknowledge as a plausible scenario (after changing address
twice), the license blurb in the source files should use the URI
for getting the license in case the library did not come with it.
Not that URIs cannot possibly change, but at least it's easier to
set up a redirection at the same place.
As a side note: this commit closes the oldes bug in Clutter's bug
report tool.
http://bugzilla.openedhand.com/show_bug.cgi?id=521
The function prototypes for the primitives API were spread between
cogl-path.h and cogl-texture.h and should have been in a
cogl-primitives.h.
As well as shuffling the prototypes around into more sensible places
this commit splits the cogl-path API out from cogl-primitives.c into
a cogl-path.c
We've had complaints that our Cogl code/headers are a bit "special" so
this is a first pass at tidying things up by giving them some
consistency. These changes are all consistent with how new code in Cogl
is being written, but the style isn't consistently applied across all
code yet.
There are two parts to this patch; but since each one required a large
amount of effort to maintain tidy indenting it made sense to combine the
changes to reduce the time spent re indenting the same lines.
The first change is to use a consistent style for declaring function
prototypes in headers. Cogl headers now consistently use this style for
prototypes:
return_type
cogl_function_name (CoglType arg0,
CoglType arg1);
Not everyone likes this style, but it seems that most of the currently
active Cogl developers agree on it.
The second change is to constrain the use of redundant glib data types
in Cogl. Uses of gint, guint, gfloat, glong, gulong and gchar have all
been replaced with int, unsigned int, float, long, unsigned long and char
respectively. When talking about pixel data; use of guchar has been
replaced with guint8, otherwise unsigned char can be used.
The glib types that we continue to use for portability are gboolean,
gint{8,16,32,64}, guint{8,16,32,64} and gsize.
The general intention is that Cogl should look palatable to the widest
range of C programmers including those outside the Gnome community so
- especially for the public API - we want to minimize the number of
foreign looking typedefs.
OpenGL is an implementation detail for Cogl so it's not appropriate to
expose OpenGL extensions through the Cogl API.
Note: Clutter is currently still using this API, because it is still
doing raw GL calls in ClutterGLXTexturePixmap, so this introduces a
couple of (legitimate) build warnings while compiling Clutter.
Some GL functions have a return value that the GE() macro is not able to
handle. Let's define a new Ge_RET() macro which will be able to handle
functions such as glMapBuffer().
While at it, removed the unused variadic dots to the GE() macro.
We were checking the number of texture units against the GL enum that is
used in glGetInteger() to query that number. Let's abstract this in a
little function.
Took the opportunity to dig a bit on the usage of GL limits for the
number of texture (image) units and document our use of them. We'll need
something finer grained if we want to fully exploit texture image units
with a programmable pipeline.
Because Cogl defines the origin for texture as top left and offscreen draw
buffers can be used to render to textures, we (internally) force all
offscreen rendering to be upside down. (because OpenGL defines the origin
to be bottom left)
By forcing the users scene to be rendered upside down though we also reverse
the winding order of all the drawn triangles which may interfere with the
users use of backface culling. This patch ensures that we reverse the
winding order for a front face (if culling is in use) while rendering
offscreen so we don't conflict with the users back face culling.
The indirection through this API isn't necessary since we no longer
arbitrate between the OpenGL matrix API and Cogl's client side API. Also it
doesn't help to maintain an OpenGL style matrix mode API for internal use
since it's awkward to keep restoring the MODELVIEW mode and easy enough to
directly work with the matrix stacks of interest.
This replaces use of the _cogl_current_matrix API with direct use of the
_cogl_matrix_stack API. All the unused cogl_current_matrix API is removed
and the matrix utility code left in cogl-current-matrix.c was moved to
cogl.c.
This relates back to an earlier commitment to stop using the OpenGL matrix
API which is considered deprecated. (ref 54159f5a1d)
The new texture matrix stacks are hung from a list of (internal only)
CoglTextureUnit structures which the CoglMaterial code internally references
via _cogl_get_texure_unit ().
So we would be left with only the cogl-matrix-stack code being responsible
for glMatrixMode, glLoadMatrix and glLoadIdentity this commit updates the
journal code so it now uses the matrix-stack API instead of GL directly.
As part of an incremental process to have Cogl be a standalone project we
want to re-consider how we organise the Cogl source code.
Currently this is the structure I'm aiming for:
cogl/
cogl/
<put common source here>
winsys/
cogl-glx.c
cogl-wgl.c
driver/
gl/
gles/
os/ ?
utils/
cogl-fixed
cogl-matrix-stack?
cogl-journal?
cogl-primitives?
pango/
The new winsys component is a starting point for migrating window system
code (i.e. x11,glx,wgl,osx,egl etc) from Clutter to Cogl.
The utils/ and pango/ directories aren't added by this commit, but they are
noted because I plan to add them soon.
Overview of the planned structure:
* The winsys/ API is the API that binds OpenGL to a specific window system,
be that X11 or win32 etc. Example are glx, wgl and egl. Much of the logic
under clutter/{glx,osx,win32 etc} should migrate here.
* Note there is also the idea of a winsys-base that may represent a window
system for which there are multiple winsys APIs. An example of this is
x11, since glx and egl may both be used with x11. (currently only Clutter
has the idea of a winsys-base)
* The driver/ represents a specific varient of OpenGL. Currently we have "gl"
representing OpenGL 1.4-2.1 (mostly fixed function) and "gles" representing
GLES 1.1 (fixed funciton) and 2.0 (fully shader based)
* Everything under cogl/ should fundamentally be supporting access to the
GPU. Essentially Cogl's most basic requirement is to provide a nice GPU
Graphics API and drawing a line between this and the utility functionality
we add to support Clutter should help keep this lean and maintainable.
* Code under utils/ as suggested builds on cogl/ adding more convenient
APIs or mechanism to optimize special cases. Broadly speaking you can
compare cogl/ to OpenGL and utils/ to GLU.
* clutter/pango will be moved to clutter/cogl/pango
How some of the internal configure.ac/pkg-config terminology has changed:
backendextra -> CLUTTER_WINSYS_BASE # e.g. "x11"
backendextralib -> CLUTTER_WINSYS_BASE_LIB # e.g. "x11/libclutter-x11.la"
clutterbackend -> {CLUTTER,COGL}_WINSYS # e.g. "glx"
CLUTTER_FLAVOUR -> {CLUTTER,COGL}_WINSYS
clutterbackendlib -> CLUTTER_WINSYS_LIB
CLUTTER_COGL -> COGL_DRIVER # e.g. "gl"
Note: The CLUTTER_FLAVOUR and CLUTTER_COGL defines are kept for apps
As the first thing to take advantage of the new winsys component in Cogl;
cogl_get_proc_address() has been moved from cogl/{gl,gles}/cogl.c into
cogl/common/cogl.c and this common implementation first trys
_cogl_winsys_get_proc_address() but if that fails then it falls back to
gmodule.
