mutter/cogl/cogl-texture-driver.h
Neil Roberts 5288f6d88d Add a Cogl texture 3D backend
This adds a publicly exposed experimental API for a 3D texture
backend. There is a feature flag which can be checked for whether 3D
textures are supported. Although we require OpenGL 1.2 which has 3D
textures in core, GLES only provides them through an extension so the
feature can be used to detect that.

The textures can be created with one of two new API functions :-

cogl_texture_3d_new_with_size

 and

cogl_texture_3d_new_from_data

There is also internally a new_from_bitmap function. new_from_data is
implemented in terms of this function.

The two constructors are effectively the only way to upload data to a
3D texture. It does not work to call glTexImage2D with the
GL_TEXTURE_3D target so the virtual for cogl_texture_set_region does
nothing. It would be possible to make cogl_texture_get_data do
something sensible like returning all of the images as a single long
image but this is not currently implemented and instead the virtual
just always fails. We may want to add API specific to the 3D texture
backend to get and set a sub region of the texture.

All of those three functions can throw a GError. This will happen if
the GPU does not support 3D textures or it does not support NPOTs and
an NPOT size is requested. It will also fail if the FBO extension is
not supported and the COGL_TEXTURE_NO_AUTO_MIPMAP flag is not
given. This could be avoided by copying the code for the
GL_GENERATE_MIPMAP TexParameter fallback, but in the interests of
keeping the code simple this is not yet done.

This adds a couple of functions to cogl-texture-driver for uploading
3D data and querying the 3D proxy
texture. prep_gl_for_pixels_upload_full now also takes sets the
GL_UNPACK_IMAGE_HEIGHT parameter so that 3D textures can have padding
between the images. Whenever 3D texture is uploading, both the height
of the images and the height of all of the data is specified (either
explicitly or implicilty from the CoglBitmap) so that the image height
can be deduced by dividing by the depth.
2010-07-13 14:28:52 +01:00

214 lines
8.2 KiB
C

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2007,2008,2009 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/>.
*
*
*/
#ifndef __COGL_TEXTURE_DRIVER_H
#define __COGL_TEXTURE_DRIVER_H
/*
* A very small wrapper around glGenTextures() that ensures we default to
* non-mipmap filters when creating textures. This is to save some memory as
* the driver will not allocate room for the mipmap tree.
*/
void
_cogl_texture_driver_gen (GLenum gl_target,
GLsizei n,
GLuint *textures);
/*
* This sets up the glPixelStore state for an upload to a destination with
* the same size, and with no offset.
*/
/* NB: GLES can't upload a sub region of pixel data from a larger source
* buffer which is why this interface is limited. The GL driver has a more
* flexible version of this function that is uses internally */
void
_cogl_texture_driver_prep_gl_for_pixels_upload (int pixels_rowstride,
int pixels_bpp);
/*
* This uploads a sub-region from source_bmp to a single GL texture handle (i.e
* a single CoglTexture slice)
*
* It also updates the array of tex->first_pixels[slice_index] if
* dst_{x,y} == 0
*
* The driver abstraction is in place because GLES doesn't support the pixel
* store options required to source from a subregion, so for GLES we have
* to manually create a transient source bitmap.
*
* XXX: sorry for the ridiculous number of arguments :-(
*/
void
_cogl_texture_driver_upload_subregion_to_gl (GLenum gl_target,
GLuint gl_handle,
gboolean is_foreign,
int src_x,
int src_y,
int dst_x,
int dst_y,
int width,
int height,
CoglBitmap *source_bmp,
GLuint source_gl_format,
GLuint source_gl_type);
/*
* Replaces the contents of the GL texture with the entire bitmap. On
* GL this just directly calls glTexImage2D, but under GLES it needs
* to copy the bitmap if the rowstride is not a multiple of a possible
* alignment value because there is no GL_UNPACK_ROW_LENGTH
*/
void
_cogl_texture_driver_upload_to_gl (GLenum gl_target,
GLuint gl_handle,
gboolean is_foreign,
CoglBitmap *source_bmp,
GLint internal_gl_format,
GLuint source_gl_format,
GLuint source_gl_type);
/*
* Replaces the contents of the GL texture with the entire bitmap. The
* width of the texture is inferred from the bitmap. The height and
* depth of the texture is given directly. The 'image_height' (which
* is the number of rows between images) is inferred by dividing the
* height of the bitmap by the depth.
*/
void
_cogl_texture_driver_upload_to_gl_3d (GLenum gl_target,
GLuint gl_handle,
gboolean is_foreign,
GLint height,
GLint depth,
CoglBitmap *source_bmp,
GLint internal_gl_format,
GLuint source_gl_format,
GLuint source_gl_type);
/*
* This sets up the glPixelStore state for an download to a destination with
* the same size, and with no offset.
*/
/* NB: GLES can't download pixel data into a sub region of a larger destination
* buffer, the GL driver has a more flexible version of this function that it
* uses internally. */
void
_cogl_texture_driver_prep_gl_for_pixels_download (int pixels_rowstride,
int pixels_bpp);
/*
* This driver abstraction is in place because GLES doesn't have a sane way to
* download data from a texture so you litterally render the texture to the
* backbuffer, and retrive the data using glReadPixels :-(
*/
gboolean
_cogl_texture_driver_download_from_gl (CoglTexture *tex,
CoglBitmap *target_bmp,
GLuint target_gl_format,
GLuint target_gl_type);
/*
* This driver abstraction is needed because GLES doesn't support glGetTexImage
* (). On GLES this currently just returns FALSE which will lead to a generic
* fallback path being used that simply renders the texture and reads it back
* from the framebuffer. (See _cogl_texture_draw_and_read () )
*/
gboolean
_cogl_texture_driver_gl_get_tex_image (GLenum gl_target,
GLenum dest_gl_format,
GLenum dest_gl_type,
guint8 *dest);
/*
* It may depend on the driver as to what texture sizes are supported...
*/
gboolean
_cogl_texture_driver_size_supported (GLenum gl_target,
GLenum gl_format,
GLenum gl_type,
int width,
int height);
gboolean
_cogl_texture_driver_size_supported_3d (GLenum gl_target,
GLenum gl_format,
GLenum gl_type,
int width,
int height,
int depth);
/*
* This driver abstraction is needed because GLES doesn't support setting
* a texture border color.
*/
void
_cogl_texture_driver_try_setting_gl_border_color (
GLuint gl_target,
const GLfloat *transparent_color);
/*
* XXX: this should live in cogl/{gl,gles}/cogl.c
*/
gboolean
_cogl_pixel_format_from_gl_internal (GLenum gl_int_format,
CoglPixelFormat *out_format);
/*
* XXX: this should live in cogl/{gl,gles}/cogl.c
*/
CoglPixelFormat
_cogl_pixel_format_to_gl (CoglPixelFormat format,
GLenum *out_glintformat,
GLenum *out_glformat,
GLenum *out_gltype);
/*
* It may depend on the driver as to what texture targets may be used when
* creating a foreign texture. E.g. OpenGL supports ARB_texture_rectangle
* but GLES doesn't
*/
gboolean
_cogl_texture_driver_allows_foreign_gl_target (GLenum gl_target);
/*
* glGenerateMipmap semantics may need to be emulated for some drivers. E.g. by
* enabling auto mipmap generation an re-loading a number of known texels.
*/
void
_cogl_texture_driver_gl_generate_mipmaps (GLenum texture_target);
/*
* The driver may impose constraints on what formats can be used to store
* texture data read from textures. For example GLES currently only supports
* RGBA_8888, and so we need to manually convert the data if the final
* destination has another format.
*/
CoglPixelFormat
_cogl_texture_driver_find_best_gl_get_data_format (
CoglPixelFormat format,
GLenum *closest_gl_format,
GLenum *closest_gl_type);
#endif /* __COGL_TEXTURE_DRIVER_H */