/*
* 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>
*/
#ifndef __COGL_TEXURE_RECTANGLE_H
#define __COGL_TEXURE_RECTANGLE_H
#include "cogl-context.h"
COGL_BEGIN_DECLS
/**
* SECTION:cogl-texture-rectangle
* @short_description: Functions for creating and manipulating rectangle
* textures for use with non-normalized coordinates.
*
* These functions allow low-level "rectangle" textures to be allocated.
* These textures are never constrained to power-of-two sizes but they
* also don't support having a mipmap and can only be wrapped with
* %COGL_PIPELINE_WRAP_MODE_CLAMP_TO_EDGE.
*
* The most notable difference between rectangle textures and 2D
* textures is that rectangle textures are sampled using un-normalized
* texture coordinates, so instead of using coordinates (0,0) and
* (1,1) to map to the top-left and bottom right corners of the
* texture you would instead use (0,0) and (width,height).
*
* The use of non-normalized coordinates can be particularly
* convenient when writing glsl shaders that use a texture as a lookup
* table since you don't need to upload separate uniforms to map
* normalized coordinates to texels.
*
* If you want to sample from a rectangle texture from GLSL you should
* use the sampler2DRect sampler type.
*
* Applications wanting to use #CoglTextureRectangle should first check
* for the %COGL_FEATURE_ID_TEXTURE_RECTANGLE feature using
* cogl_has_feature().
*/
typedef struct _CoglTextureRectangle CoglTextureRectangle;
#define COGL_TEXTURE_RECTANGLE(X) ((CoglTextureRectangle *)X)
/**
* cogl_is_texture_rectangle:
* @object: A #CoglObject
*
* Gets whether the given object references an existing
* #CoglTextureRectangle object.
*
* Return value: %TRUE if the object references a
* #CoglTextureRectangle, %FALSE otherwise.
*/
CoglBool
cogl_is_texture_rectangle (void *object);
/**
* cogl_texture_rectangle_new_with_size:
* @ctx: A #CoglContext pointer
* @width: The texture width to allocate
* @height: The texture height to allocate
* @internal_format: The desired internal texture format
* @error: An optional CoglError pointer for reporting exceptions
*
* Allocates a new #CoglTextureRectangle texture with a given @width, @height
* and @internal_format. This texture is a low-level texture that
* the GPU can sample from directly unlike high-level textures such
* as #CoglTexture2DSliced and #CoglAtlasTexture.
*
* <note>Unlike for #CoglTexture2D textures, coordinates for
* #CoglTextureRectangle textures should not be normalized. So instead
* of using the coordinate (1, 1) to sample the bottom right corner of
* a rectangle texture you would use (@width, @height) where @width
* and @height are the width and height of the texture.</note>
*
* <note>If you want to sample from a rectangle texture from GLSL you
* should use the sampler2DRect sampler type.</note>
*
* <note>Applications wanting to use #CoglTextureRectangle should
* first check for the %COGL_FEATURE_ID_TEXTURE_RECTANGLE feature
* using cogl_has_feature().</note>
*
* <note>For compatibility, unlike other texture constructors, this
* api allocates texture storage synchronously and returns %NULL on
* failure so it is not possible to configure rectangle textures
* created with this api before allocation.</note>
*
* Return value: (transfer full): A pointer to a newly allocated
* #CoglTextureRectangle texture or if the size was too large
* or there wasn't enough memory %NULL is returned and @error
* set.
*
* Since: 1.10
* Stability: unstable
*/
CoglTextureRectangle *
cogl_texture_rectangle_new_with_size (CoglContext *ctx,
int width,
int height,
CoglPixelFormat internal_format,
CoglError **error);
/**
* cogl_texture_rectangle_new_from_bitmap:
* @bitmap: A #CoglBitmap
* @internal_format: the #CoglPixelFormat to use for the GPU storage of the
* texture
* @error: A return location for a CoglError or %NULL
*
* Allocates a new #CoglTextureRectangle texture which will be
* initialized with the pixel data from @bitmap. Internally the data
* will be stored in the format given by @internal_format. This
* texture is a low-level texture that the GPU can sample from
* directly unlike high-level textures such as #CoglTexture2DSliced
* and #CoglAtlasTexture.
*
* <note>Unlike for #CoglTexture2D textures, coordinates for
* #CoglTextureRectangle textures should not be normalized. So instead
* of using the coordinate (1, 1) to sample the bottom right corner of
* a rectangle texture you would use (@width, @height) where @width
* and @height are the width and height of the texture.</note>
*
* <note>If you want to sample from a rectangle texture from GLSL you
* should use the sampler2DRect sampler type.</note>
*
* <note>Applications wanting to use #CoglTextureRectangle should
* first check for the %COGL_FEATURE_ID_TEXTURE_RECTANGLE feature
* using cogl_has_feature().</note>
*
* The storage for the texture is not allocated before this function
* returns. You can call cogl_texture_allocate() to explicitly
* allocate the underlying storage or preferably let Cogl
* automatically allocate storage lazily when it may know more about
* how the texture is going to be used and can optimize how it is
* allocated.
*
* Return value: (transfer full): A pointer to a newly allocated
* #CoglTextureRectangle texture or if the size was too large
* or there wasn't enough memory %NULL is returned and @error
* set.
*
* Since: 2.0
* Stability: unstable
*/
CoglTextureRectangle *
cogl_texture_rectangle_new_from_bitmap (CoglBitmap *bitmap,
CoglPixelFormat internal_format,
CoglError **error);
/**
* cogl_texture_rectangle_new_from_foreign:
* @ctx: A #CoglContext
* @gl_handle: A GL handle for a GL_TEXTURE_RECTANGLE texture object
* @width: Width of the foreign GL texture
* @height: Height of the foreign GL texture
* @format: The format of the texture
* @error: A #CoglError for exceptions
*
* Wraps an existing GL_TEXTURE_RECTANGLE texture object as a
* #CoglTextureRectangle. This can be used for integrating Cogl with
* software using OpenGL directly.
*
* <note>Unlike for #CoglTexture2D textures, coordinates for
* #CoglTextureRectangle textures should not be normalized. So instead
* of using the coordinate (1, 1) to sample the bottom right corner of
* a rectangle texture you would use (@width, @height) where @width
* and @height are the width and height of the texture.</note>
*
* <note>The results are undefined for passing an invalid @gl_handle
* or if @width or @height don't have the correct texture
* geometry.</note>
*
* <note>If you want to sample from a rectangle texture from GLSL you
* should use the sampler2DRect sampler type.</note>
*
* <note>Applications wanting to use #CoglTextureRectangle should
* first check for the %COGL_FEATURE_ID_TEXTURE_RECTANGLE feature
* using cogl_has_feature().</note>
*
* The texture is still configurable until it has been allocated so
* for example you can declare whether the texture is premultiplied
* with cogl_texture_set_premultiplied().
*
* Return value: (transfer full): A newly allocated
* #CoglTextureRectangle, 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.
*/
CoglTextureRectangle *
cogl_texture_rectangle_new_from_foreign (CoglContext *ctx,
unsigned int gl_handle,
int width,
int height,
CoglPixelFormat format,
CoglError **error);
COGL_END_DECLS
#endif /* __COGL_TEXURE_RECTANGLE_H */