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mutter/cogl/cogl-atlas.c
Neil Roberts c8ddb3b55a cogl-atlas: Try 4 different approaches for migrating textures 
Instead of directly banging GL to migrate textures the atlas now uses
the CoglFramebuffer API. It will use one of four approaches; it can
set up two FBOs and use _cogl_blit_framebuffer to copy between them;
it can use a single target fbo and then render the source texture to
the FBO using a Cogl draw call; it can use a single FBO and call
glCopyTexSubImage2D; or it can fallback to reading all of the texture
data back to system memory and uploading it again with a sub texture
update.

Previously GL calls were used directly because Cogl wasn't able to
create a framebuffer without a stencil and depth buffer. However there
is now an internal version of cogl_offscreen_new_to_texture which
takes a set of flags to disable the two buffers.

The code for blitting has now been moved into a separate file called
cogl-blit.c because it has become quite long and it may be useful
outside of the atlas at some point.

The 4 different methods have a fixed order of preference which is:

* Texture render between two FBOs
* glBlitFramebuffer
* glCopyTexSubImage2D
* glGetTexImage + glTexSubImage2D

Once a method is succesfully used it is tried first for all subsequent
blits. The default default can be overridden by setting the
environment variable COGL_ATLAS_DEFAULT_BLIT_MODE to one of the
following values:

* texture-render
* framebuffer
* copy-tex-sub-image
* get-tex-data
2011-02-15 12:10:54 +00:00

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/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2010 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, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*
* Authors:
* Neil Roberts <neil@linux.intel.com>
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "cogl.h"
#include "cogl-atlas.h"
#include "cogl-rectangle-map.h"
#include "cogl-context.h"
#include "cogl-texture-private.h"
#include "cogl-texture-2d-private.h"
#include "cogl-texture-driver.h"
#include "cogl-pipeline-opengl-private.h"
#include "cogl-debug.h"
#include "cogl-framebuffer-private.h"
#include "cogl-blit.h"
#include <stdlib.h>
static void _cogl_atlas_free (CoglAtlas *atlas);
COGL_OBJECT_INTERNAL_DEFINE (Atlas, atlas);
CoglAtlas *
_cogl_atlas_new (CoglPixelFormat texture_format,
CoglAtlasFlags flags,
CoglAtlasUpdatePositionCallback update_position_cb)
{
CoglAtlas *atlas = g_new (CoglAtlas, 1);
atlas->update_position_cb = update_position_cb;
atlas->map = NULL;
atlas->texture = NULL;
atlas->flags = flags;
atlas->texture_format = texture_format;
_cogl_callback_list_init (&atlas->reorganize_callbacks);
return _cogl_atlas_object_new (atlas);
}
static void
_cogl_atlas_free (CoglAtlas *atlas)
{
COGL_NOTE (ATLAS, "%p: Atlas destroyed", atlas);
if (atlas->texture)
cogl_handle_unref (atlas->texture);
if (atlas->map)
_cogl_rectangle_map_free (atlas->map);
_cogl_callback_list_destroy (&atlas->reorganize_callbacks);
g_free (atlas);
}
typedef struct _CoglAtlasRepositionData
{
/* The current user data for this texture */
void *user_data;
/* The old and new positions of the texture */
CoglRectangleMapEntry old_position;
CoglRectangleMapEntry new_position;
} CoglAtlasRepositionData;
static void
_cogl_atlas_migrate (CoglAtlas *atlas,
unsigned int n_textures,
CoglAtlasRepositionData *textures,
CoglHandle old_texture,
CoglHandle new_texture,
void *skip_user_data)
{
unsigned int i;
CoglBlitData blit_data;
/* If the 'disable migrate' flag is set then we won't actually copy
the textures to their new location. Instead we'll just invoke the
callback to update the position */
if ((atlas->flags & COGL_ATLAS_DISABLE_MIGRATION))
for (i = 0; i < n_textures; i++)
/* Update the texture position */
atlas->update_position_cb (textures[i].user_data,
new_texture,
&textures[i].new_position);
else
{
_cogl_blit_begin (&blit_data, new_texture, old_texture);
for (i = 0; i < n_textures; i++)
{
/* Skip the texture that is being added because it doesn't contain
any data yet */
if (textures[i].user_data != skip_user_data)
_cogl_blit (&blit_data,
textures[i].old_position.x,
textures[i].old_position.y,
textures[i].new_position.x,
textures[i].new_position.y,
textures[i].new_position.width,
textures[i].new_position.height);
/* Update the texture position */
atlas->update_position_cb (textures[i].user_data,
new_texture,
&textures[i].new_position);
}
_cogl_blit_end (&blit_data);
}
}
typedef struct _CoglAtlasGetRectanglesData
{
CoglAtlasRepositionData *textures;
/* Number of textures found so far */
unsigned int n_textures;
} CoglAtlasGetRectanglesData;
static void
_cogl_atlas_get_rectangles_cb (const CoglRectangleMapEntry *rectangle,
void *rect_data,
void *user_data)
{
CoglAtlasGetRectanglesData *data = user_data;
data->textures[data->n_textures].old_position = *rectangle;
data->textures[data->n_textures++].user_data = rect_data;
}
static void
_cogl_atlas_get_next_size (unsigned int *map_width,
unsigned int *map_height)
{
/* Double the size of the texture by increasing whichever dimension
is smaller */
if (*map_width < *map_height)
*map_width <<= 1;
else
*map_height <<= 1;
}
static void
_cogl_atlas_get_initial_size (CoglPixelFormat format,
unsigned int *map_width,
unsigned int *map_height)
{
unsigned int size;
GLenum gl_intformat;
GLenum gl_type;
_cogl_pixel_format_to_gl (format,
&gl_intformat,
NULL, /* gl_format */
&gl_type);
/* At least on Intel hardware, the texture size will be rounded up
to at least 1MB so we might as well try to aim for that as an
initial minimum size. If the format is only 1 byte per pixel we
can use 1024x1024, otherwise we'll assume it will take 4 bytes
per pixel and use 512x512. */
if (_cogl_get_format_bpp (format) == 1)
size = 1024;
else
size = 512;
/* Some platforms might not support this large size so we'll
decrease the size until it can */
while (size > 1 &&
!_cogl_texture_driver_size_supported (GL_TEXTURE_2D,
gl_intformat,
gl_type,
size, size))
size >>= 1;
*map_width = size;
*map_height = size;
}
static CoglRectangleMap *
_cogl_atlas_create_map (CoglPixelFormat format,
unsigned int map_width,
unsigned int map_height,
unsigned int n_textures,
CoglAtlasRepositionData *textures)
{
GLenum gl_intformat;
GLenum gl_type;
_cogl_pixel_format_to_gl (format,
&gl_intformat,
NULL, /* gl_format */
&gl_type);
/* Keep trying increasingly larger atlases until we can fit all of
the textures */
while (_cogl_texture_driver_size_supported (GL_TEXTURE_2D,
gl_intformat,
gl_type,
map_width, map_height))
{
CoglRectangleMap *new_atlas = _cogl_rectangle_map_new (map_width,
map_height,
NULL);
unsigned int i;
COGL_NOTE (ATLAS, "Trying to resize the atlas to %ux%u",
map_width, map_height);
/* Add all of the textures and keep track of the new position */
for (i = 0; i < n_textures; i++)
if (!_cogl_rectangle_map_add (new_atlas,
textures[i].old_position.width,
textures[i].old_position.height,
textures[i].user_data,
&textures[i].new_position))
break;
/* If the atlas can contain all of the textures then we have a
winner */
if (i >= n_textures)
return new_atlas;
else
COGL_NOTE (ATLAS, "Atlas size abandoned after trying "
"%u out of %u textures",
i, n_textures);
_cogl_rectangle_map_free (new_atlas);
_cogl_atlas_get_next_size (&map_width, &map_height);
}
/* If we get here then there's no atlas that can accommodate all of
the rectangles */
return NULL;
}
static CoglHandle
_cogl_atlas_create_texture (CoglAtlas *atlas,
int width,
int height)
{
CoglHandle tex;
if ((atlas->flags & COGL_ATLAS_CLEAR_TEXTURE))
{
guint8 *clear_data;
CoglBitmap *clear_bmp;
int bpp = _cogl_get_format_bpp (atlas->texture_format);
/* Create a buffer of zeroes to initially clear the texture */
clear_data = g_malloc0 (width * height * bpp);
clear_bmp = _cogl_bitmap_new_from_data (clear_data,
atlas->texture_format,
width,
height,
width * bpp,
(CoglBitmapDestroyNotify) g_free,
NULL);
tex = _cogl_texture_2d_new_from_bitmap (clear_bmp, COGL_TEXTURE_NONE,
atlas->texture_format);
cogl_object_unref (clear_bmp);
}
else
tex = _cogl_texture_2d_new_with_size (width, height, COGL_TEXTURE_NONE,
atlas->texture_format);
return tex;
}
static int
_cogl_atlas_compare_size_cb (const void *a,
const void *b)
{
const CoglAtlasRepositionData *ta = a;
const CoglAtlasRepositionData *tb = b;
unsigned int a_size, b_size;
a_size = ta->old_position.width * ta->old_position.height;
b_size = tb->old_position.width * tb->old_position.height;
return a_size < b_size ? 1 : a_size > b_size ? -1 : 0;
}
static void
_cogl_atlas_notify_reorganize (CoglAtlas *atlas)
{
_cogl_callback_list_invoke (&atlas->reorganize_callbacks);
}
gboolean
_cogl_atlas_reserve_space (CoglAtlas *atlas,
unsigned int width,
unsigned int height,
void *user_data)
{
CoglAtlasGetRectanglesData data;
CoglRectangleMap *new_map;
CoglHandle new_tex;
unsigned int map_width, map_height;
gboolean ret;
CoglRectangleMapEntry new_position;
/* Check if we can fit the rectangle into the existing map */
if (atlas->map &&
_cogl_rectangle_map_add (atlas->map, width, height,
user_data,
&new_position))
{
int waste =
_cogl_rectangle_map_get_remaining_space (atlas->map) *
100 / (_cogl_rectangle_map_get_width (atlas->map) *
_cogl_rectangle_map_get_height (atlas->map));
COGL_NOTE (ATLAS, "%p: Atlas is %ix%i, has %i textures and is %i%% waste",
atlas,
_cogl_rectangle_map_get_width (atlas->map),
_cogl_rectangle_map_get_height (atlas->map),
_cogl_rectangle_map_get_n_rectangles (atlas->map),
waste);
atlas->update_position_cb (user_data,
atlas->texture,
&new_position);
return TRUE;
}
/* We need to reorganise the atlas so we'll get an array of all the
textures currently in the atlas. */
data.n_textures = 0;
if (atlas->map == NULL)
data.textures = g_malloc (sizeof (CoglAtlasRepositionData));
else
{
unsigned int n_rectangles =
_cogl_rectangle_map_get_n_rectangles (atlas->map);
data.textures = g_malloc (sizeof (CoglAtlasRepositionData) *
(n_rectangles + 1));
_cogl_rectangle_map_foreach (atlas->map,
_cogl_atlas_get_rectangles_cb,
&data);
}
/* Add the new rectangle as a dummy texture so that it can be
positioned with the rest */
data.textures[data.n_textures].old_position.x = 0;
data.textures[data.n_textures].old_position.y = 0;
data.textures[data.n_textures].old_position.width = width;
data.textures[data.n_textures].old_position.height = height;
data.textures[data.n_textures++].user_data = user_data;
/* The atlasing algorithm works a lot better if the rectangles are
added in decreasing order of size so we'll first sort the
array */
qsort (data.textures, data.n_textures,
sizeof (CoglAtlasRepositionData),
_cogl_atlas_compare_size_cb);
/* Try to create a new atlas that can contain all of the textures */
if (atlas->map)
{
map_width = _cogl_rectangle_map_get_width (atlas->map);
map_height = _cogl_rectangle_map_get_height (atlas->map);
/* If there is enough space in for the new rectangle in the
existing atlas with at least 6% waste we'll start with the
same size, otherwise we'll immediately double it */
if ((map_width * map_height -
_cogl_rectangle_map_get_remaining_space (atlas->map) +
width * height) * 53 / 50 >
map_width * map_height)
_cogl_atlas_get_next_size (&map_width, &map_height);
}
else
_cogl_atlas_get_initial_size (atlas->texture_format,
&map_width, &map_height);
new_map = _cogl_atlas_create_map (atlas->texture_format,
map_width, map_height,
data.n_textures, data.textures);
/* If we can't create a map with the texture then give up */
if (new_map == NULL)
{
COGL_NOTE (ATLAS, "%p: Could not fit texture in the atlas", atlas);
ret = FALSE;
}
/* We need to migrate the existing textures into a new texture */
else if ((new_tex = _cogl_atlas_create_texture
(atlas,
_cogl_rectangle_map_get_width (new_map),
_cogl_rectangle_map_get_height (new_map))) == COGL_INVALID_HANDLE)
{
COGL_NOTE (ATLAS, "%p: Could not create a CoglTexture2D", atlas);
_cogl_rectangle_map_free (new_map);
ret = FALSE;
}
else
{
int waste;
_cogl_atlas_notify_reorganize (atlas);
COGL_NOTE (ATLAS,
"%p: Atlas %s with size %ix%i",
atlas,
atlas->map == NULL ||
_cogl_rectangle_map_get_width (atlas->map) !=
_cogl_rectangle_map_get_width (new_map) ||
_cogl_rectangle_map_get_height (atlas->map) !=
_cogl_rectangle_map_get_height (new_map) ?
"resized" : "reorganized",
_cogl_rectangle_map_get_width (new_map),
_cogl_rectangle_map_get_height (new_map));
if (atlas->map)
{
/* Move all the textures to the right position in the new
texture. This will also update the texture's rectangle */
_cogl_atlas_migrate (atlas,
data.n_textures,
data.textures,
atlas->texture,
new_tex,
user_data);
_cogl_rectangle_map_free (atlas->map);
cogl_handle_unref (atlas->texture);
}
else
/* We know there's only one texture so we can just directly
update the rectangle from its new position */
atlas->update_position_cb (data.textures[0].user_data,
new_tex,
&data.textures[0].new_position);
atlas->map = new_map;
atlas->texture = new_tex;
waste = (_cogl_rectangle_map_get_remaining_space (atlas->map) *
100 / (_cogl_rectangle_map_get_width (atlas->map) *
_cogl_rectangle_map_get_height (atlas->map)));
COGL_NOTE (ATLAS, "%p: Atlas is %ix%i, has %i textures and is %i%% waste",
atlas,
_cogl_rectangle_map_get_width (atlas->map),
_cogl_rectangle_map_get_height (atlas->map),
_cogl_rectangle_map_get_n_rectangles (atlas->map),
waste);
ret = TRUE;
}
g_free (data.textures);
return ret;
}
void
_cogl_atlas_remove (CoglAtlas *atlas,
const CoglRectangleMapEntry *rectangle)
{
_cogl_rectangle_map_remove (atlas->map, rectangle);
COGL_NOTE (ATLAS, "%p: Removed rectangle sized %ix%i",
atlas,
rectangle->width,
rectangle->height);
COGL_NOTE (ATLAS, "%p: Atlas is %ix%i, has %i textures and is %i%% waste",
atlas,
_cogl_rectangle_map_get_width (atlas->map),
_cogl_rectangle_map_get_height (atlas->map),
_cogl_rectangle_map_get_n_rectangles (atlas->map),
_cogl_rectangle_map_get_remaining_space (atlas->map) *
100 / (_cogl_rectangle_map_get_width (atlas->map) *
_cogl_rectangle_map_get_height (atlas->map)));
};
CoglHandle
_cogl_atlas_copy_rectangle (CoglAtlas *atlas,
unsigned int x,
unsigned int y,
unsigned int width,
unsigned int height,
CoglTextureFlags flags,
CoglPixelFormat format)
{
CoglHandle tex;
CoglBlitData blit_data;
/* Create a new texture at the right size */
tex = cogl_texture_new_with_size (width, height, flags, format);
/* Blit the data out of the atlas to the new texture. If FBOs
aren't available this will end up having to copy the entire
atlas texture */
_cogl_blit_begin (&blit_data, tex, atlas->texture);
_cogl_blit (&blit_data,
x, y,
0, 0,
width, height);
_cogl_blit_end (&blit_data);
return tex;
}
void
_cogl_atlas_add_reorganize_callback (CoglAtlas *atlas,
CoglCallbackListFunc callback,
void *user_data)
{
_cogl_callback_list_add (&atlas->reorganize_callbacks, callback, user_data);
}
void
_cogl_atlas_remove_reorganize_callback (CoglAtlas *atlas,
CoglCallbackListFunc callback,
void *user_data)
{
_cogl_callback_list_remove (&atlas->reorganize_callbacks,
callback, user_data);
}
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