Similar to the widely used gluLookAt API, this adds a CoglMatrix utility
for setting up a view transform in terms of positioning a camera/eye
position that points to a given object position aligned to a given
world-up vector.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
This adds a function called cogl_matrix_is_identity that can determine
if a given matrix is an identity matrix or not.
Signed-off-by: Neil Roberts <neil@linux.intel.com>
To help catch accidental changes to the size of public structs that can
be allocated on the stack this patch adds compile time checks that our
struct sizes haven't changed.
This adds an experimental quaternion utility API. It's not yet fully
documented but it's complete enough that people can start to experiment
with using it. It adds the following functions:
cogl_quaternion_init_identity
cogl_quaternion_init
cogl_quaternion_init_from_angle_vector
cogl_quaternion_init_from_array
cogl_quaternion_init_from_x_rotation
cogl_quaternion_init_from_y_rotation
cogl_quaternion_init_from_z_rotation
cogl_quaternion_equal
cogl_quaternion_copy
cogl_quaternion_free
cogl_quaternion_get_rotation_angle
cogl_quaternion_get_rotation_axis
cogl_quaternion_normalize
cogl_quaternion_dot_product
cogl_quaternion_invert
cogl_quaternion_multiply
cogl_quaternion_pow
cogl_quaternion_slerp
cogl_quaternion_nlerp
cogl_quaternion_squad
cogl_get_static_identity_quaternion
cogl_get_static_zero_quaternion
Since it's experimental API you'll need to define
COGL_ENABLE_EXPERIMENTAL_API before including cogl.h.
Instead of unconditionally combining the modelview and projection
matrices and then iterating each of the vertices to call
cogl_matrix_transform_point for each one in turn we now only combine the
matrices if there are more than 4 vertices (with less than 4 vertices
its less work to transform them separately) and we use the new
cogl_vertex_{transform,project}_points APIs which can hopefully
vectorize the transformations.
Finally the perspective divide and viewport scale is done in a separate
loop at the end and we don't do the spurious perspective divide and
viewport scale for the z component.
This adds two new experimental functions to cogl-matrix.c:
cogl_matrix_view_2d_in_perspective and cogl_matrix_view_2d_in_frustum
which can be used to setup a view transform that maps a 2D coordinate
system (0,0) top left and (width,height) bottom right to the current
viewport.
Toolkits such as Clutter that want to mix 2D and 3D drawing can use
these APIs to position a 2D coordinate system at an arbitrary depth
inside a 3D perspective projected viewing frustum.
This adds a note to clarify that cogl_matrix_multiply allows you to
multiply the @a matrix in-place, so @a can equal @result but @b can't
equal @result.
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.
As a pre-requisite for being able to register a boxed GType for
CoglMatrix (enabling us to define gobject properties that accept a
CoglMatrix) this adds cogl_matrix_copy and _free functions.
This add two new function that allows us to transform or project an
array of points instead of only transforming one point at a time. Recent
benchmarking has shown cogl_matrix_transform_point to be a bottleneck
sometimes, so this should allow us to reduce the overhead when
transforming lots of vertices at the same time, and also reduce the cost
of 3 component, non-projective transforms.
For now they are marked as experimental (you have to define
COGL_ENABLE_EXPERIMENTAL_API) because there is some concern that it
introduces some inconsistent naming. cogl_matrix_transform_point would
have to be renamed cogl_matrix_project_point to be consistent, but that
would be an API break.
This adds a way to compare two CoglMatrix structures to see if they
represent the same transformations. memcmp can't be used because a
CoglMatrix contains private flags and padding.
CoglColor and CoglMatrix have public declarations with private members
so that we are free to change the implementation but the structures
could still be allocated on the stack in applications. However it's
quite easy not to realise the members are private and then access them
directly. This patch wraps the members in a macro which redefines the
symbol name when including the header outside of the clutter source.
http://bugzilla.openedhand.com/show_bug.cgi?id=2065
The xx, yx, zx etc fields are meant to be read-only but they were
marked as private with the gtk-doc annotation. This patch moves the
private marker so that the 16 float member fields are public but the
type, inverted matrix, flags and padding are not.
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
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.
This new API takes advantage of the recently imported Mesa code to support
inverse matrix calculation. The matrix code keeps track (via internal
flags) of the transformations a matrix represents so that it can select an
optimized inversion function.
Note: although other aspects of the Cogl matrix API have followed a similar
style to Cairo's matrix API we haven't added a cogl_matrix_invert API
because the inverse of a CoglMatrix is actually cached as part of the
CoglMatrix structure meaning a destructive API like cogl_matrix_invert
doesn't let users take advantage of this caching design.
This pulls in code from Mesa to improve our matrix manipulation support. It
includes support for calculating the inverse of matrices based on top of a
matrix categorizing system that allows optimizing certain matrix types.
(the main thing we were after) but also adds some optimisations for
rotations.
Changes compared to the original code from Mesa:
- Coding style is consistent with the rest of Cogl
- Instead of allocating matrix->m and matrix->inv using malloc, our public
CoglMatrix typedef is large enough to directly contain the matrix, its
inverse, a type and a set of flags.
- Instead of having a _math_matrix_analyse which updates the type, flags and
inverse, we have _math_matrix_update_inverse which essentially does the
same thing (internally making use of _math_matrix_update_type_and_flags())
but with additional guards in place to bail out when the inverse matrix is
still valid.
- When initializing a matrix with the identity matrix we don't immediately
initialize the inverse matrix; rather we just set the dirty flag for the
inverse (since it's likely the user won't request the inverse of the
identity matrix)
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.
