mutter/cogl/cogl-texture-2d.h
Robert Bragg df21e20f65 Adds CoglError api
Although we use GLib internally in Cogl we would rather not leak GLib
api through Cogl's own api, except through explicitly namespaced
cogl_glib_ / cogl_gtype_ feature apis.

One of the benefits we see to not leaking GLib through Cogl's public API
is that documentation for Cogl won't need to first introduce the Glib
API to newcomers, thus hopefully lowering the barrier to learning Cogl.

This patch provides a Cogl specific typedef for reporting runtime errors
which by no coincidence matches the typedef for GError exactly.  If Cogl
is built with --enable-glib (default) then developers can even safely
assume that a CoglError is a GError under the hood.

This patch also enforces a consistent policy for when NULL is passed as
an error argument and an error is thrown. In this case we log the error
and abort the application, instead of silently ignoring it. In common
cases where nothing has been implemented to handle a particular error
and/or where applications are just printing the error and aborting
themselves then this saves some typing. This also seems more consistent
with language based exceptions which usually cause a program to abort if
they are not explicitly caught (which passing a non-NULL error signifies
in this case)

Since this policy for NULL error pointers is stricter than the standard
GError convention, there is a clear note in the documentation to warn
developers that are used to using the GError api.

Reviewed-by: Neil Roberts <neil@linux.intel.com>

(cherry picked from commit b068d5ea09ab32c37e8c965fc8582c85d1b2db46)

Note: Since we can't change the Cogl 1.x api the patch was changed to
not rename _error_quark() functions to be _error_domain() functions and
although it's a bit ugly, instead of providing our own CoglError type
that's compatible with GError we simply #define CoglError to GError
unless Cogl is built with glib disabled.

Note: this patch does technically introduce an API break since it drops
the cogl_error_get_type() symbol generated by glib-mkenum (Since the
CoglError enum was replaced by a CoglSystemError enum) but for now we
are assuming that this will not affect anyone currently using the Cogl
API. If this does turn out to be a problem in practice then we would be
able to fix this my manually copying an implementation of
cogl_error_get_type() generated by glib-mkenum into a compatibility
source file and we could also define the original COGL_ERROR_ enums for
compatibility too.

Note: another minor concern with cherry-picking this patch to the 1.14
branch is that an api scanner would be lead to believe that some APIs
have changed, and for example the gobject-introspection parser which
understands the semantics of GError will not understand the semantics of
CoglError. We expect most people that have tried to use
gobject-introspection with Cogl already understand though that it is not
well suited to generating bindings of the Cogl api anyway and we aren't
aware or anyone depending on such bindings for apis involving GErrors.
(GnomeShell only makes very-very minimal use of Cogl via the gjs
bindings for the cogl_rectangle and cogl_color apis.)

The main reason we have cherry-picked this patch to the 1.14 branch
even given the above concerns is that without it it would become very
awkward for us to cherry-pick other beneficial patches from master.
2013-01-22 17:47:39 +00:00

225 lines
8.4 KiB
C

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2011 Intel Corporation.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <http://www.gnu.org/licenses/>.
*
*
* Authors:
* Robert Bragg <robert@linux.intel.com>
*/
#if !defined(__COGL_H_INSIDE__) && !defined(COGL_COMPILATION)
#error "Only <cogl/cogl.h> can be included directly."
#endif
#ifndef __COGL_TEXTURE_2D_H
#define __COGL_TEXTURE_2D_H
#include "cogl-context.h"
#include <glib.h>
G_BEGIN_DECLS
/**
* SECTION:cogl-texture-2d
* @short_description: Functions for creating and manipulating 2D textures
*
* These functions allow low-level 2D textures to be allocated. These
* differ from sliced textures for example which may internally be
* made up of multiple 2D textures, or atlas textures where Cogl must
* internally modify user texture coordinates before they can be used
* by the GPU.
*
* You should be aware that many GPUs only support power of two sizes
* for #CoglTexture2D textures. You can check support for non power of
* two textures by checking for the %COGL_FEATURE_ID_TEXTURE_NPOT feature
* via cogl_has_feature().
*/
typedef struct _CoglTexture2D CoglTexture2D;
#define COGL_TEXTURE_2D(X) ((CoglTexture2D *)X)
/**
* cogl_is_texture_2d:
* @object: A #CoglObject
*
* Gets whether the given object references an existing #CoglTexture2D
* object.
*
* Return value: %TRUE if the object references a #CoglTexture2D,
* %FALSE otherwise
*/
CoglBool
cogl_is_texture_2d (void *object);
/**
* cogl_texture_2d_new_with_size:
* @ctx: A #CoglContext
* @width: Width of the texture to allocate
* @height: Height of the texture to allocate
* @internal_format: The format of the texture
* @error: A #CoglError for exceptions
*
* Allocates a low-level #CoglTexture2D texture that your GPU can
* texture from directly. This is unlike sliced textures for example
* which may be comprised of multiple internal textures, or atlas
* textures where Cogl has to modify texture coordinates before they
* may be used by the GPU.
*
* <note>Many GPUs only support power of two sizes for #CoglTexture2D
* textures. You can check support for non power of two textures by
* checking for the %COGL_FEATURE_ID_TEXTURE_NPOT feature via
* cogl_has_feature().</note>
*
* Returns: A newly allocated #CoglTexture2D, or if the size is not
* supported (because it is too large or a non-power-of-two
* size that the hardware doesn't support) it will return
* %NULL and set @error.
*
* Since: 2.0
*/
CoglTexture2D *
cogl_texture_2d_new_with_size (CoglContext *ctx,
int width,
int height,
CoglPixelFormat internal_format,
CoglError **error);
/**
* cogl_texture_2d_new_from_data:
* @ctx: A #CoglContext
* @width: width of texture in pixels
* @height: height of texture in pixels
* @format: the #CoglPixelFormat the buffer is stored in in RAM
* @internal_format: the #CoglPixelFormat that will be used for storing
* the buffer on the GPU. If %COGL_PIXEL_FORMAT_ANY is given then a
* premultiplied format similar to the format of the source data will
* be used. The default blending equations of Cogl expect premultiplied
* color data; the main use of passing a non-premultiplied format here
* is if you have non-premultiplied source data and are going to adjust
* the blend mode (see cogl_pipeline_set_blend()) or use the data for
* something other than straight blending.
* @rowstride: the memory offset in bytes between the starts of
* scanlines in @data. A value of 0 will make Cogl automatically
* calculate @rowstride from @width and @format.
* @data: pointer the memory region where the source buffer resides
* @error: A #CoglError for exceptions
*
* Creates a new #CoglTexture2D texture based on data residing in memory.
* These are unlike sliced textures for example which may be comprised
* of multiple internal textures, or atlas textures where Cogl has to
* modify texture coordinates before they may be used by the GPU.
*
* <note>Many GPUs only support power of two sizes for #CoglTexture2D
* textures. You can check support for non power of two textures by
* checking for the %COGL_FEATURE_ID_TEXTURE_NPOT feature via
* cogl_has_feature().</note>
*
* Returns: A newly allocated #CoglTexture2D, or if the size is not
* supported (because it is too large or a non-power-of-two
* size that the hardware doesn't support) it will return
* %NULL and set @error.
*
* Since: 2.0
*/
CoglTexture2D *
cogl_texture_2d_new_from_data (CoglContext *ctx,
int width,
int height,
CoglPixelFormat format,
CoglPixelFormat internal_format,
int rowstride,
const uint8_t *data,
CoglError **error);
/**
* cogl_texture_2d_new_from_bitmap:
* @bitmap: A #CoglBitmap
* @internal_format: the #CoglPixelFormat that will be used for storing
* the buffer on the GPU. If %COGL_PIXEL_FORMAT_ANY is given then a
* premultiplied format similar to the format of the source data will
* be used. The default blending equations of Cogl expect premultiplied
* color data; the main use of passing a non-premultiplied format here
* is if you have non-premultiplied source data and are going to adjust
* the blend mode (see cogl_pipeline_set_blend()) or use the data for
* something other than straight blending.
* @error: A #CoglError for exceptions
*
* Creates a new #CoglTexture2D texture based on data residing in a
* bitmap. These are unlike sliced textures for example which may be
* comprised of multiple internal textures, or atlas textures where
* Cogl has to modify texture coordinates before they may be used by
* the GPU.
*
* <note>Many GPUs only support power of two sizes for #CoglTexture2D
* textures. You can check support for non power of two textures by
* checking for the %COGL_FEATURE_ID_TEXTURE_NPOT feature via
* cogl_has_feature().</note>
*
* Returns: A newly allocated #CoglTexture2D, or if the size is not
* supported (because it is too large or a non-power-of-two
* size that the hardware doesn't support) it will return
* %NULL and set @error.
*
* Since: 2.0
* Stability: unstable
*/
CoglTexture2D *
cogl_texture_2d_new_from_bitmap (CoglBitmap *bitmap,
CoglPixelFormat internal_format,
CoglError **error);
/**
* cogl_texture_2d_new_from_foreign:
* @ctx: A #CoglContext
* @gl_handle: A GL handle for a GL_TEXTURE_2D texture object
* @width: Width of the foreign GL texture
* @height: Height of the foreign GL texture
* @internal_format: The format of the texture
* @error: A #CoglError for exceptions
*
* Wraps an existing GL_TEXTURE_2D texture object as a #CoglTexture2D.
* This can be used for integrating Cogl with software using OpenGL
* directly.
*
* <note>The results are undefined for passing an invalid @gl_handle
* or if @width or @height don't have the correct texture
* geometry.</note>
*
* Returns: A newly allocated #CoglTexture2D, or if Cogl could not
* validate the @gl_handle in some way (perhaps because of
* an unsupported format) it will return %NULL and set
* @error.
*
* Since: 2.0
*/
CoglTexture2D *
cogl_texture_2d_new_from_foreign (CoglContext *ctx,
unsigned int gl_handle,
int width,
int height,
CoglPixelFormat format,
CoglError **error);
G_END_DECLS
#endif /* __COGL_TEXTURE_2D_H */