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6253b09c69
This make the CoglTexture2DSliced type public and adds cogl_texture_2d_sliced_new_with_size() as an experimental API that can be used to construct a sliced texture without any initial data. Reviewed-by: Neil Roberts <neil@linux.intel.com>
105 lines
4.2 KiB
C
105 lines
4.2 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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#define cogl_texture_2d_sliced_new_with_size \
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cogl_texture_2d_sliced_new_with_size_EXP
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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 #GError 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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GError **error);
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#endif /* __COGL_TEXURE_2D_SLICED_H */
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