df21e20f65
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.
116 lines
4.5 KiB
C
116 lines
4.5 KiB
C
/*
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* Cogl
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*
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* An object oriented GL/GLES Abstraction/Utility Layer
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*
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* Copyright (C) 2011 Intel Corporation.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library. If not, see
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* <http://www.gnu.org/licenses/>.
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*
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*
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* Authors:
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* Robert Bragg <robert@linux.intel.com>
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*/
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#ifndef __COGL_TEXURE_2D_SLICED_H
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#define __COGL_TEXURE_2D_SLICED_H
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#include "cogl-context.h"
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#include "cogl-types.h"
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#include <glib.h>
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/**
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* SECTION:cogl-texture-2d-sliced
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* @short_description: Functions for creating and manipulating 2D meta
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* textures that may internally be comprised of
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* multiple 2D textures with power-of-two sizes.
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*
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* These functions allow high-level meta textures (See the
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* #CoglMetaTexture interface) to be allocated that may internally be
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* comprised of multiple 2D texture "slices" with power-of-two sizes.
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*
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* This API can be useful when working with GPUs that don't have
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* native support for non-power-of-two textures or if you want to load
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* a texture that is larger than the GPUs maximum texture size limits.
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*
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* The algorithm for slicing works by first trying to map a virtual
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* size to the next larger power-of-two size and then seeing how many
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* wasted pixels that would result in. For example if you have a
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* virtual texture that's 259 texels wide, the next pot size = 512 and
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* the amount of waste would be 253 texels. If the amount of waste is
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* above a max-waste threshold then we would next slice that texture
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* into one that's 256 texels and then looking at how many more texels
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* remain unallocated after that we choose the next power-of-two size.
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* For the example of a 259 texel image that would mean having a 256
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* texel wide texture, leaving 3 texels unallocated so we'd then
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* create a 4 texel wide texture - now there is only one texel of
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* waste. The algorithm continues to slice the right most textures
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* until the amount of waste is less than or equal to a specfied
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* max-waste threshold. The same logic for slicing from left to right
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* is also applied from top to bottom.
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*/
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typedef struct _CoglTexture2DSliced CoglTexture2DSliced;
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#define COGL_TEXTURE_2D_SLICED(X) ((CoglTexture2DSliced *)X)
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/**
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* cogl_texture_2d_sliced_new_with_size:
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* @ctx: A #CoglContext
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* @width: The virtual width of your sliced texture.
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* @height: The virtual height of your sliced texture.
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* @max_waste: The threshold of how wide a strip of wasted texels
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* are allowed in the non-power-of-two textures before
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* they must be sliced to reduce the amount of waste.
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* @internal_format: The format of the texture
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* @error: A #CoglError for exceptions.
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*
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* Creates a #CoglTexture2DSliced that may internally be comprised of
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* 1 or more #CoglTexture2D textures with power-of-two sizes.
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* @max_waste is used as a threshold for recursively slicing the
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* right-most or bottom-most slices into smaller power-of-two sizes
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* until the wasted padding at the bottom and right of the
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* power-of-two textures is less than specified.
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*
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* Returns: A newly allocated #CoglTexture2DSliced or if there was
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* an error allocating any of the internal slices %NULL is
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* returned and @error is updated.
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*
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* Since: 1.10
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* Stability: unstable
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*/
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CoglTexture2DSliced *
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cogl_texture_2d_sliced_new_with_size (CoglContext *ctx,
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unsigned int width,
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unsigned int height,
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int max_waste,
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CoglPixelFormat internal_format,
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CoglError **error);
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/**
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* cogl_is_texture_2d_sliced:
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* @object: A #CoglObject pointer
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*
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* Gets whether the given object references a #CoglTexture2dSliced.
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*
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* Return value: %TRUE if the object references a #CoglTexture2dSliced
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* and %FALSE otherwise.
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* Since: 1.10
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* Stability: unstable
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*/
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CoglBool
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cogl_is_texture_2d_sliced (void *object);
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#endif /* __COGL_TEXURE_2D_SLICED_H */
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