73e8a6d7ce
Consistent with how we lazily allocate framebuffers this patch allows us to instantiate textures but still specify constraints and requirements before allocating storage so that we can be sure to allocate the most appropriate/efficient storage. This adds a cogl_texture_allocate() function that is analogous to cogl_framebuffer_allocate() which can optionally be called to explicitly allocate storage and catch any errors. If this function isn't used explicitly then Cogl will implicitly ensure textures are allocated before the storage is needed. It is generally recommended to rely on lazy storage allocation or at least perform explicit allocation as late as possible so Cogl can be fully informed about the best way to allocate storage. Reviewed-by: Neil Roberts <neil@linux.intel.com> (cherry picked from commit 1fa7c0f10a8a03043e3c75cb079a49625df098b7) Note: This reverts the cogl_texture_rectangle_new_with_size API change that dropped the CoglError argument and keeps the semantics of allocating the texture immediately. This is because Mutter currently uses this API so we will probably look at updating this later once we have a corresponding Mutter patch prepared. The other API changes were kept since they only affected experimental api.
130 lines
5.2 KiB
C
130 lines
5.2 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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/**
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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 along the right and bottom textures before
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* they must be sliced to reduce the amount of waste. A
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* negative can be passed to disable slicing.
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* @internal_format: The format of the texture
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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 depending on GPU limitations.
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* For example if the GPU only supports power-of-two sized textures
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* then a sliced texture will turn a non-power-of-two size into a
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* combination of smaller power-of-two sized textures. If the
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* requested texture size is larger than is supported by the hardware
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* then the texture will be sliced into smaller textures that can be
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* accessed by the hardware.
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*
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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 sizes until the
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* wasted padding at the bottom and right of the textures is less than
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* specified. A negative @max_waste will disable slicing.
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*
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* The storage for the texture is not allocated before this function
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* returns. You can call cogl_texture_allocate() to explicitly
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* allocate the underlying storage or let Cogl automatically allocate
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* storage lazily.
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*
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* <note>It's possible for the allocation of a sliced texture to fail
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* later due to impossible slicing constraints if a negative
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* @max_waste value is given. If the given virtual texture size size
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* is larger than is supported by the hardware but slicing is disabled
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* the texture size would be too large to handle.</note>
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*
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* Returns: A new #CoglTexture2DSliced object with no storage
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* allocated yet.
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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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int width,
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int height,
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int max_waste,
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CoglPixelFormat internal_format);
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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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