90f106117f
This exposes CoglTextureRectangle in the experimental cogl 2.0 api. For now we just expose a single constructor; cogl_texture_rectangle_new_with_size() but we can add more later. This is part of going work to improve our texture apis with more emphasis on providing low-level access to the varying semantics of different texture types understood by the gpu instead of only trying to present a lowest common denominator api. CoglTextureRectangle is notably useful for never being restricted to power of two sizes and for being sampled with non-normalized texture coordinates which can be convenient for use a lookup tables in glsl due to not needing separate uniforms for mapping normalized coordinates to texels. Unlike CoglTexture2D though rectangle textures can't have a mipmap and they only support the _CLAMP_TO_EDGE wrap mode. Applications wanting to use CoglTextureRectangle should first check cogl_has_feature (COGL_FEATURE_ID_TEXTURE_RECTANGLE). Reviewed-by: Neil Roberts <neil@linux.intel.com>
118 lines
4.2 KiB
C
118 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_RECTANGLE_H
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#define __COGL_TEXURE_RECTANGLE_H
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#include "cogl-context.h"
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G_BEGIN_DECLS
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/**
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* SECTION:cogl-texture-rectangle
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* @short_description: Functions for creating and manipulating rectangle
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* textures for use with non-normalized coordinates.
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*
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* These functions allow low-level "rectangle" textures to be allocated.
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* These textures are never constrained to power-of-two sizes but they
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* also don't support having a mipmap and can only be wrapped with
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* %COGL_PIPELINE_WRAP_MODE_CLAMP_TO_EDGE.
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*
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* The most notable difference between rectangle textures and 2D
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* textures is that rectangle textures are sampled using un-normalized
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* texture coordinates, so instead of using coordinates (0,0) and
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* (1,1) to map to the top-left and bottom right corners of the
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* texture you would instead use (0,0) and (width,height).
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*
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* The use of non-normalized coordinates can be particularly
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* convenient when writing glsl shaders that use a texture as a lookup
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* table since you don't need to upload separate uniforms to map
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* normalized coordinates to texels.
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*
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* If you want to sample from a rectangle texture from GLSL you should
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* use the sampler2DRect sampler type.
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*
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* Applications wanting to use #CoglTextureRectangle should first check
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* for the %COGL_FEATURE_ID_TEXTURE_RECTANGLE feature using
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* cogl_has_feature().
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*/
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typedef struct _CoglTextureRectangle CoglTextureRectangle;
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#define COGL_TEXTURE_RECTANGLE(X) ((CoglTextureRectangle *)X)
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#define cogl_is_texture_rectangle cogl_is_texture_rectangle_EXP
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/**
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* cogl_is_texture_rectangle:
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* @object: A #CoglObject
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*
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* Gets whether the given object references an existing
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* #CoglTextureRectangle object.
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*
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* Return value: %TRUE if the object references a
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* #CoglTextureRectangle, %FALSE otherwise.
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*/
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gboolean
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cogl_is_texture_rectangle (void *object);
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#define cogl_texture_rectangle_new_with_size \
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cogl_texture_rectangle_new_with_size_EXP
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/**
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* cogl_texture_rectangle_new_with_size:
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* @context: A #CoglContext pointer
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* @width: The texture width to allocate
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* @height: The texture height to allocate
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* @internal_format: The desired internal texture format
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* @error: An optional GError pointer for reporting exceptions
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*
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* Allocates a new #CoglRectangle texture with a given @width, @height
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* and @internal_format. This texture is a low-level texture that
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* the GPU can sample from directly unlike high-level textures such
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* as #CoglTexture2DSliced and #CoglAtlasTexture.
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*
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* <note>If you want to sample from a rectangle texture from GLSL you
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* should use the sampler2DRect sampler type.</note>
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*
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* <note>Applications wanting to use #CoglTextureRectangle should
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* first check for the %COGL_FEATURE_ID_TEXTURE_RECTANGLE feature
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* using cogl_has_feature().</note>
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*
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* Returns: A pointer to a newly allocated #CoglRectangle texture
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* or if the size was too large or there wasn't enough memory
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* %NULL is returned and @error set.
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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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CoglTextureRectangle *
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cogl_texture_rectangle_new_with_size (CoglContext *ctx,
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int width,
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int height,
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CoglPixelFormat internal_format,
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GError **error);
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G_END_DECLS
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#endif /* __COGL_TEXURE_RECTANGLE_H */
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