Commit Graph

93 Commits

Author SHA1 Message Date
Robert Bragg
d74cf9de81 matrix: Adds cogl_matrix_is_identity API
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>
2011-07-04 15:31:50 +01:00
Robert Bragg
ee7cc9e788 Make CoglTexture2D public as experimental API
This exposes a CoglTexture2D typedef and adds the following experimental
API:
    cogl_is_texture_2d
    cogl_texture_2d_new_with_size
    cogl_texture_2d_new_from_data
    cogl_texture_2d_new_from_foreign

Since this is experimental API you need to define
COGL_ENABLE_EXPERIMENTAL_API before including cogl.h.

Note: With these new entrypoints we now expect a CoglContext pointer to
be passed in, instead of assuming there is a default context. The aim is
that for Cogl 2.0 we won't have a default context so this is a step in
that direction.
2011-06-01 20:44:41 +01:00
Robert Bragg
07c0b9f89f Add CoglDepthState API
Instead of simply extending the cogl_pipeline_ namespace to add api for
controlling the depth testing state we now break the api out. This adds
a CoglDepthState type that can be stack allocated. The members of the
structure are private but we have the following API to setup the state:

    cogl_depth_state_init
    cogl_depth_state_set_test_enabled
    cogl_depth_state_get_test_enabled
    cogl_depth_state_set_test_function
    cogl_depth_state_get_test_function
    cogl_depth_state_set_writing_enabled
    cogl_depth_state_get_writing_enabled
    cogl_depth_state_set_range
    cogl_depth_state_get_range

This removes the following experimental API which is now superseded:

    cogl_material_set_depth_test_enabled
    cogl_material_get_depth_test_enabled
    cogl_material_set_depth_test_function
    cogl_material_get_depth_test_function
    cogl_material_set_depth_writing_enabled
    cogl_material_get_depth_writing_enabled
    cogl_material_set_depth_range
    cogl_material_get_depth_range

Once a CoglDepthState structure is setup it can be set on a pipeline
using cogl_pipeline_set_depth_state().
2011-05-16 18:36:44 +01:00
Robert Bragg
df1915d957 math: Adds an experimental euler API
This adds an experimental CoglEuler data type and the following new
functions:

    cogl_euler_init
    cogl_euler_init_from_matrix
    cogl_euler_init_from_quaternion
    cogl_euler_equal
    cogl_euler_copy
    cogl_euler_free
    cogl_quaternion_init_from_euler

Since this is experimental API you need to define
COGL_ENABLE_EXPERIMENTAL_API before including cogl.h
2011-05-16 14:12:42 +01:00
Robert Bragg
d1434d1c33 math: Adds an experimental quaternion API
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.
2011-05-16 14:11:47 +01:00
Emmanuele Bassi
aa4f63338c docs: Fixes for the Cogl API reference 2010-12-22 09:52:35 +00:00
Robert Bragg
fd10e3a545 matrix gtype: registers a boxed type for CoglMatrix
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.
2010-12-07 12:16:50 +00:00
Robert Bragg
e9e824fd86 matrix: Adds experimental cogl_matrix_{transform,project}_points
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.
2010-11-23 12:50:29 +00:00
Robert Bragg
1b9a247174 cogl: Adds {push,pop,get}_source functions
This exposes the idea of a stack of source materials instead of just
having a single current material. This allows the writing of orthogonal
code that can change the current source material and restore it to its
previous state. It also allows the implementation of new composite
primitives that may want to validate the current source material and
possibly make override changes in a derived material.
2010-10-26 12:08:20 +01:00
Robert Bragg
8150292879 docs: Put deprecated Cogl symbols into new section
This adds a "Cogl deprecated API" chapter to the Cogl reference manual
so we can group all the documentation for deprecated symbols together
instead of having them clutter up the documentation of symbols we would
rather developers used.
2010-09-23 15:53:30 +01:00
Robert Bragg
8d80a88e14 cogl-program: Adds use_uniform_xyz methods
Instead of exposing an API that provides an OpenGL state machine style
where you first have to bind the program to the context using
cogl_program_use() followed by updating uniforms using
cogl_program_uniform_xyz we now have uniform setter methods that take an
explicit CoglHandle for the program.

This deprecates cogl_program_use and all the cogl_program_uniform
variants and provides the following replacements:
    cogl_program_set_uniform_1i
    cogl_program_set_uniform_1f
    cogl_program_set_uniform_int
    cogl_program_set_uniform_float
    cogl_program_set_uniform_matrix
2010-08-12 16:50:46 +01:00
Neil Roberts
671abec8b7 Make the material functions for setting the p wrap mode public
Now that we have 3D texture support it makes sense to expose the wrap
mode for the p coordinate.
2010-07-13 14:29:07 +01:00
Neil Roberts
5288f6d88d Add a Cogl texture 3D backend
This adds a publicly exposed experimental API for a 3D texture
backend. There is a feature flag which can be checked for whether 3D
textures are supported. Although we require OpenGL 1.2 which has 3D
textures in core, GLES only provides them through an extension so the
feature can be used to detect that.

The textures can be created with one of two new API functions :-

cogl_texture_3d_new_with_size

 and

cogl_texture_3d_new_from_data

There is also internally a new_from_bitmap function. new_from_data is
implemented in terms of this function.

The two constructors are effectively the only way to upload data to a
3D texture. It does not work to call glTexImage2D with the
GL_TEXTURE_3D target so the virtual for cogl_texture_set_region does
nothing. It would be possible to make cogl_texture_get_data do
something sensible like returning all of the images as a single long
image but this is not currently implemented and instead the virtual
just always fails. We may want to add API specific to the 3D texture
backend to get and set a sub region of the texture.

All of those three functions can throw a GError. This will happen if
the GPU does not support 3D textures or it does not support NPOTs and
an NPOT size is requested. It will also fail if the FBO extension is
not supported and the COGL_TEXTURE_NO_AUTO_MIPMAP flag is not
given. This could be avoided by copying the code for the
GL_GENERATE_MIPMAP TexParameter fallback, but in the interests of
keeping the code simple this is not yet done.

This adds a couple of functions to cogl-texture-driver for uploading
3D data and querying the 3D proxy
texture. prep_gl_for_pixels_upload_full now also takes sets the
GL_UNPACK_IMAGE_HEIGHT parameter so that 3D textures can have padding
between the images. Whenever 3D texture is uploading, both the height
of the images and the height of all of the data is specified (either
explicitly or implicilty from the CoglBitmap) so that the image height
can be deduced by dividing by the depth.
2010-07-13 14:28:52 +01:00
Neil Roberts
42dcffbc3a Make a public CoglBitmapError enum
There are many places in the texture backend that need to do
conversion using the CoglBitmap code. Currently none of these
functions can throw an error but they do return a value to indicate
failure. In future it would make sense if new texture functions could
throw an error and in that case they would want to use a CoglBitmap
error if the failure was due to the conversion. This moves the
internal CoglBitmap error from the quartz backend to be public in
cogl-bitmap.h so that it can be used in this way.
2010-07-13 14:28:45 +01:00
Neil Roberts
9e3705ecb3 Add cogl_vertex_buffer_is_indices to the public headers
This function has always been defined in the shared library but it was
missed from the public headers.
2010-07-09 18:57:54 +01:00
Neil Roberts
da3be3df6b cogl-material: Add support for point sprites
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
2010-07-08 16:34:30 +01:00
Neil Roberts
06b58baa10 cogl-material: Add a property for setting the point size
This adds cogl_material_{get,set}_point_size. If the point size is not
1.0f then glPointSize will be called when the material is flushed.

http://bugzilla.openedhand.com/show_bug.cgi?id=2047
2010-07-08 16:34:30 +01:00
Emmanuele Bassi
be6335c870 docs: Add a cogl-paths section
The path primitives have a specific section, now, and gtk-doc is loudly
complaining about it being defined but not referenced.
2010-07-02 17:49:09 +01:00
Neil Roberts
432c37bd21 Add CoglMaterialWrapMode to the Cogl docs and fix docs for the getters
CoglMaterialWrapMode was missing from the cogl-sections.txt file so it
wasn't getting displayed. There were also no documented return values
from the getters.
2010-07-02 17:29:34 +01:00
Neil Roberts
cdf5b222db cogl-path: Allow changing the fill rule
This adds two new API calls- cogl_path_set_fill_rule and
cogl_path_get_fill_rule. This allows modifying the fill rule of the
current path. In addition to the previous default fill rule of
'even-odd' it now supports the 'non-zero' rule. The fill rule is a
property of the path (not the Cogl context) so creating a new path or
preserving a path with cogl_path_get_handle affects the fill rule.
2010-06-29 20:37:14 +01:00
Damien Lespiau
98f2d2516b cogl-color: Provide setters for all the channels
We only had getters for the red, green, blue and alpha channels of a
color. This meant that, if you wanted to change, say, the alpha
component of a color, one would need to query the red, green and blue
channels and use set_from_4ub() or set_from_4f().

Instead of this, just provide some setters for CoglColor, using the same
naming scheme than the existing getters.
2010-06-10 20:02:01 +01:00
Damien Lespiau
896dd975d1 cogl-color: Add cogl_color_unpremultiply()
For some operations on pre-multiplied colors (say, replace the alpha
value), you need to unpremultiply the color.

This patch provides the counterpart to cogl_color_premultiply().
2010-06-10 20:01:48 +01:00
Damien Lespiau
2e52c5f67b doc: Some fixes for the Cogl documentation
• 3 general fixes (typos, copy/paste),
 • ignore cogl-object-private.h,
 • cogl_fixed_atani() was in reality cogl_fixed_atan(), fixed in commit
   43564f05.
 • Fix the cogl-vector section: sections must have a </SECTION> tag at
   the end. Also the cogl-vector section was added in the middle of the
   cogl-buffer one. Let's shiffle it out and add that </SECTION> tag.
2010-06-07 14:32:32 +01:00
Robert Bragg
5af3ead3a2 CoglObject: Adds cogl_object_{get,set}_user_data
This provides a mechanism for associating private data with any
CoglObject. We expect Clutter will use this to associate weak materials
with normal materials.
2010-06-04 14:44:15 +01:00
Robert Bragg
ef08c6369a cogl-path: Adds missing cogl_is_path prototype
This adds a missing cogl_is_path prototype to the public cogl-path.h
header.
2010-06-04 14:44:15 +01:00
Robert Bragg
368dc48372 cogl-path: Renames cogl_path_get/set cogl_get/set_path
These aren't path methods so aren't consistent with the
cogl_object_method naming style we are aiming for.
2010-06-04 14:44:15 +01:00
Robert Bragg
fa22ee0e8d math: Adds an experimental cogl_vector3_* API
This adds a math utility API for handling 3 component, single precision
float vectors with the following; mostly self explanatory functions:

cogl_vector3_init
cogl_vector3_init_zero
cogl_vector3_equal
cogl_vector3_equal_with_epsilon
cogl_vector3_copy
cogl_vector3_free
cogl_vector3_invert
cogl_vector3_add
cogl_vector3_subtract
cogl_vector3_multiply_scalar
cogl_vector3_divide_scalar
cogl_vector3_normalize
cogl_vector3_magnitude
cogl_vector3_cross_product
cogl_vector3_dot_product
cogl_vector3_distance

Since the API is experimental you will need to define
COGL_ENABLE_EXPERIMENTAL_API before including cogl.h if you want to use
the API.
2010-05-20 17:18:24 +01:00
Neil Roberts
e007bc5358 cogl-material: Add support for setting the wrap mode for a layer
Previously, Cogl's texture coordinate system was effectively always
GL_REPEAT so that if an application specifies coordinates outside the
range 0→1 it would get repeated copies of the texture. It would
however change the mode to GL_CLAMP_TO_EDGE if all of the coordinates
are in the range 0→1 so that in the common case that the whole texture
is being drawn with linear filtering it will not blend in edge pixels
from the opposite sides.

This patch adds the option for applications to change the wrap mode
per layer. There are now three wrap modes: 'repeat', 'clamp-to-edge'
and 'automatic'. The automatic map mode is the default and it
implements the previous behaviour. The wrap mode can be changed for
the s and t coordinates independently. I've tried to make the
internals support setting the r coordinate but as we don't support 3D
textures yet I haven't exposed any public API for it.

The texture backends still have a set_wrap_mode virtual but this value
is intended to be transitory and it will be changed whenever the
material is flushed (although the backends are expected to cache it so
that it won't use too many GL calls). In my understanding this value
was always meant to be transitory and all primitives were meant to set
the value before drawing. However there were comments suggesting that
this is not the expected behaviour. In particular the vertex buffer
drawing code never set a wrap mode so it would end up with whatever
the texture was previously used for. These issues are now fixed
because the material will always set the wrap modes.

There is code to manually implement clamp-to-edge for textures that
can't be hardware repeated. However this doesn't fully work because it
relies on being able to draw the stretched parts using quads with the
same values for tx1 and tx2. The texture iteration code doesn't
support this so it breaks. This is a separate bug and it isn't
trivially solved.

When flushing a material there are now extra options to set wrap mode
overrides. The overrides are an array of values for each layer that
specifies an override for the s, t or r coordinates. The primitives
use this to implement the automatic wrap mode. cogl_polygon also uses
it to set GL_CLAMP_TO_BORDER mode for its trick to render sliced
textures. Although this code has been added it looks like the sliced
trick has been broken for a while and I haven't attempted to fix it
here.

I've added a constant to represent the maximum number of layers that a
material supports so that I can size the overrides array. I've set it
to 32 because as far as I can tell we have that limit imposed anyway
because the other flush options use a guint32 to store a flag about
each layer. The overrides array ends up adding 32 bytes to each flush
options struct which may be a concern.

http://bugzilla.openedhand.com/show_bug.cgi?id=2063
2010-04-12 15:44:23 +01:00
Neil Roberts
067a520f26 cogl: Support retained paths
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.
2010-04-08 19:53:38 +01:00
Robert Bragg
d1353b3c1a cogl: renames cogl_multiply_matrix to cogl_transform
Although cogl_multiply_matrix was consistent with OpenGL, after further
consideration it was agreed that cogl_transform is a better name. Given
that it's in the global cogl_ namespace cogl_transform seems more self
documenting.
2010-04-08 14:37:01 +01:00
Emmanuele Bassi
395518fb34 docs: Fixes for Cogl 2010-02-12 15:52:07 +00:00
Emmanuele Bassi
62fa1f9c28 docs: Clean up the unused symbols for Cogl
Gtk-doc is reporting a lot of false positives in the unused text file,
mostly because of new private files that have been added to Cogl but not
to the gtk-doc ignore list for the Cogl API reference.

Once the false positives have been removed we have a couple of really
missing symbols that should be added to the cogl-sections.txt file.
2010-02-09 15:29:29 +00:00
Emmanuele Bassi
ea0d0f1231 docs: Move some Cogl defines in the private section
The PixelFormat bit and mask #defines should not be used and are there
mostly for convenience, so we can push them to the "private" sub-section
of the API reference.

This pushed Cogl's API reference coverage to 100%.
2010-02-09 14:48:11 +00:00
Emmanuele Bassi
2674a1ead2 docs: Fixes for Cogl API reference
98% symbol docs coverage.
  335 symbols documented.
  0 symbols incomplete.
  8 not documented.

Not bad, if I may say so.
2010-02-09 14:41:37 +00:00
Damien Lespiau
cf960cfb3d cogl-texture: Add a new constructor to turn CoglBuffers into textures
The only goal of using COGL buffers is to use them to create
textures. cogl_texture_new_from_buffer() is the new symbol to create
textures out of buffers.
2010-02-08 17:14:49 +00:00
Damien Lespiau
47cc5a4e43 cogl-pixel-buffer: add a pixel buffer object class
This subclass of CoglBuffer aims at wrapping PBOs or other system
surfaces like DRM buffer objects. Two constructors are available:

cogl_pixel_buffer_new() with a size when you only care about the size of
the buffer (such a buffer can be used to store several texture data such
as the three planes of a I420 frame).

cogl_pixel_buffer_new_full() is more a 1:1 mapping between the data and
an underlying surface, with the possibility of having access to a low
level memory buffer that may have a stride.
2010-02-08 17:14:49 +00:00
Damien Lespiau
40b73a8c0c cogl-buffer: add an abstract class around openGL's buffer objects
Buffer objects are cool! This abstracts the buffer API first introduced
by GL_ARB_vertex_buffer_object and then extended to other objects.

The coglBuffer abstract class is intended to be the base class of all
the buffer objects, letting the user map() buffers. If the underlying
implementation does not support buffer objects (or only support VBO but
not FBO for instance), fallback paths should be provided.
2010-02-08 17:14:49 +00:00
Neil Roberts
c9cafc798c cogl: Add a sub texture backend
This adds a new texture backend which represents a sub texture of a
larger texture. The texture is created with a reference to the full
texture and a set of coordinates describing the region. The backend
simply defers to the full texture for all operations and maps the
coordinates to the other range. You can also use coordinates outside
the range [0,1] to create a repeated version of the full texture.

A new public API function called cogl_texture_new_from_sub_texture is
available to create the sub texture.
2009-12-02 22:03:08 +00:00
Robert Bragg
944423a8d9 cogl: deprecate cogl_draw_buffer API and replace with a cogl_framebuffer API
cogl_push_draw_buffer, cogl_set_draw_buffer and cogl_pop_draw_buffer are now
deprecated and new code should use the new cogl_framebuffer_* API instead.

Code that previously did:
    cogl_push_draw_buffer ();
    cogl_set_draw_buffer (COGL_OFFSCREEN_BUFFER, buffer);
    /* draw */
    cogl_pop_draw_buffer ();
should now be re-written as:
    cogl_push_framebuffer (buffer);
    /* draw */
    cogl_pop_framebuffer ();

As can be seen from the example above the rename has been used as an
opportunity to remove the redundant target argument from
cogl_set_draw_buffer; it now only takes one call to redirect to an offscreen
buffer, and finally the term framebuffer may be a bit more familiar to
anyone coming from an OpenGL background.
2009-11-26 19:33:14 +00:00
Robert Bragg
d2ce4f7137 docs: Don't document cogl_flush_gl_state as public API
This function was #if 0'd before we released Clutter 1.0 so there's no
implementation of it.  At some point we thought it might assist with
developers breaking out into raw OpenGL.  Breaking out to raw GL is a
difficult problem though so we decided instead we will wait for a specific
use case to arrise before trying to support it.
2009-11-24 17:58:22 +00:00
Emmanuele Bassi
bae4b213d3 docs: Fix Cogl API reference build
• Ignore all the private header files

• Add all missing/unused symbols

• Remove deprecated symbols from 0.*
2009-11-19 13:56:42 +00:00
Robert Bragg
2e0e441031 [cogl-clip] deprecate parts and cleanup the API
cogl_clip_push() which accepts a rectangle in model space shouldn't have
been defined to take x,y,width,height arguments because this isn't consistant
with other Cogl API dealing with model space rectangles.  If you are using a
coordinate system with the origin at the center and the y+ extending up,
then x,y,width,height isn't as natural as (x0,y0)(x1,y1). This API has
now been replace with cogl_clip_push_rectangle()

(As a general note: the Cogl API should only use the x,y,width,height style
when the appropriate coordinate space is defined by Cogl to have a top left
origin.  E.g.  window coordinates, or potentially texture coordinates)

cogl_clip_push_window_rect() shouldn't have been defined to take float
arguments since we only clip with integral pixel precision. We also
shouldn't have abbreviated "rectangle". This API has been replaced with
cogl_clip_push_window_rectangle()

cogl_clip_ensure() wasn't documented at all in Clutter 1.0 and probably
no one even knew it existed. This API isn't useful, and so it's now
deprecated. If no one complains we may remove the API altogether for
Clutter 1.2.

cogl_clip_stack_save() and cogl_clip_stack_restore() were originally added
to allow us to save/restore the clip when switching to/from offscreen
rendering.  Now that offscreen draw buffers are defined to own their clip
state and the state will be automatically saved and restored this API is now
redundant and so deprecated.
2009-11-05 21:10:17 +00:00
Emmanuele Bassi
76480b466f docs: Add the "clipping" section to the COGL API reference
All the clip-related API in COGL is missing from the API reference
because the cogl-clipping section is not included inside the main
index file.
2009-10-07 17:41:54 +01:00
Emmanuele Bassi
ff833fa068 [cogl] Expose cogl_is_vertex_buffer()
The function is public and available in the shared object, but
it's not present in the header, so this is not an API/ABI change.
2009-08-04 11:15:05 +01:00
Emmanuele Bassi
d1b8cab65d [doc] Miscellaneous documentation fixes
Remove private symbols, and add missing public ones.
2009-07-20 12:49:35 +01:00
Robert Bragg
afe10f9897 [doc] Remove references to cogl_vertex_buffer_delete_indices
These referencese were left over from before indices got CoglHandles to
uniquely identify them.  cogl_handle_unref can be used to delete indices
now.
2009-07-19 10:23:00 +01:00
Robert Bragg
b4bc9eb458 [cogl] Improve ability to break out into raw OpenGL via begin/end mechanism
Although we wouldn't recommend developers try and interleve OpenGL drawing
with Cogl drawing - we would prefer patches that improve Cogl to avoid this
if possible - we are providing a simple mechanism that will at least give
developers a fighting chance if they find it necissary.

Note: we aren't helping developers change OpenGL state to modify the
behaviour of Cogl drawing functions - it's unlikley that can ever be
reliably supported - but if they are trying to do something like:

   - setup some OpenGL state.
   - draw using OpenGL (e.g. glDrawArrays() )
   - reset modified OpenGL state.
   - continue using Cogl to draw

They should surround their blocks of raw OpenGL with cogl_begin_gl() and
cogl_end_gl():

   cogl_begin_gl ();
   - setup some OpenGL state.
   - draw using OpenGL (e.g. glDrawArrays() )
   - reset modified OpenGL state.
   cogl_end_gl ();
   - continue using Cogl to draw

Again; we aren't supporting code like this:
   - setup some OpenGL state.
   - use Cogl to draw
   - reset modified OpenGL state.
When the internals of Cogl evolves, this is very liable to break.

cogl_begin_gl() will flush all internally batched Cogl primitives, and emit
all internal Cogl state to OpenGL as if it were going to draw something
itself.

The result is that the OpenGL modelview matrix will be setup; the state
corresponding to the current source material will be setup and other world
state such as backface culling, depth and fogging enabledness will be also
be sent to OpenGL.

Note: no special material state is flushed, so if developers want Cogl to setup
a simplified material state it is the their responsibility to set a simple
source material before calling cogl_begin_gl. E.g. by calling
cogl_set_source_color4ub().

Note: It is the developers responsibility to restore any OpenGL state that they
modify to how it was after calling cogl_begin_gl() if they don't do this then
the result of further Cogl calls is undefined.
2009-06-30 17:13:38 +01:00
Robert Bragg
99f53c3922 Adds a cogl_flush() to give developers breaking into raw GL a fighting chance
This function should only need to be called in exceptional circumstances
since Cogl can normally determine internally when a flush is necessary.

As an optimization Cogl drawing functions may batch up primitives
internally, so if you are trying to use raw GL outside of Cogl you stand a
better chance of being successful if you ask Cogl to flush any batched
geometry before making your state changes.

cogl_flush() ensures that the underlying driver is issued all the commands
necessary to draw the batched primitives.  It provides no guarantees about
when the driver will complete the rendering.

This provides no guarantees about the GL state upon returning and to avoid
confusing Cogl you should aim to restore any changes you make before
resuming use of Cogl.

If you are making state changes with the intention of affecting Cogl drawing
primitives you are 100% on your own since you stand a good chance of
conflicting with Cogl internals.  For example clutter-gst which currently
uses direct GL calls to bind ARBfp programs will very likely break when Cogl
starts to use ARBfb programs internally for the material API, but for now it
can use cogl_flush() to at least ensure that the ARBfp program isn't applied
to additional primitives.

This does not provide a robust generalized solution supporting safe use of
raw GL, its use is very much discouraged.
2009-06-30 17:13:38 +01:00
Robert Bragg
606fb8f56f [cogl] Adds cogl_read_pixels to replace direct use of glReadPixels
To allow for flushing of batched geometry within Cogl we can't support users
directly calling glReadPixels.  glReadPixels is also awkward, not least
because it returns upside down image data.

All the unit tests have been swithed over and clutter_stage_read_pixels now
sits on top of this too.
2009-06-29 23:49:06 +01:00
Emmanuele Bassi
e0adc985ad [docs] Various gtk-doc fixes for COGL
Try to keep the gtk-doc errors down to a minimum.
2009-06-10 12:57:36 +01:00