mutter/cogl/cogl-atlas.c
Emmanuele Bassi 72f4ddf532 Remove mentions of the FSF address
Since using addresses that might change is something that finally
the FSF acknowledge as a plausible scenario (after changing address
twice), the license blurb in the source files should use the URI
for getting the license in case the library did not come with it.

Not that URIs cannot possibly change, but at least it's easier to
set up a redirection at the same place.

As a side note: this commit closes the oldes bug in Clutter's bug
report tool.

http://bugzilla.openedhand.com/show_bug.cgi?id=521
2010-03-01 12:56:10 +00:00

599 lines
17 KiB
C

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 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/>.
*
*
*
* Authors:
* Neil Roberts <neil@linux.intel.com>
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <glib.h>
#include "cogl-atlas.h"
#include "cogl-debug.h"
/* Implements a data structure which keeps track of unused
sub-rectangles within a larger rectangle using a binary tree
structure. The algorithm for this is based on the description here:
http://www.blackpawn.com/texts/lightmaps/default.html
*/
#ifdef COGL_ENABLE_DEBUG
/* The cairo header is only used for debugging to generate an image of
the atlas */
#include <cairo.h>
static void _cogl_atlas_dump_image (CoglAtlas *atlas);
#endif /* COGL_ENABLE_DEBUG */
typedef struct _CoglAtlasNode CoglAtlasNode;
typedef struct _CoglAtlasStackEntry CoglAtlasStackEntry;
typedef void (* CoglAtlasInternalForeachCb) (CoglAtlasNode *node,
gpointer data);
typedef enum
{
COGL_ATLAS_BRANCH,
COGL_ATLAS_FILLED_LEAF,
COGL_ATLAS_EMPTY_LEAF
} CoglAtlasNodeType;
struct _CoglAtlas
{
CoglAtlasNode *root;
unsigned int space_remaining;
unsigned int n_rectangles;
GDestroyNotify value_destroy_func;
};
struct _CoglAtlasNode
{
CoglAtlasNodeType type;
CoglAtlasRectangle rectangle;
CoglAtlasNode *parent;
union
{
/* Fields used when this is a branch */
struct
{
CoglAtlasNode *left;
CoglAtlasNode *right;
} branch;
/* Field used when this is a filled leaf */
gpointer data;
} d;
};
struct _CoglAtlasStackEntry
{
/* The node to search */
CoglAtlasNode *node;
/* Index of next branch of this node to explore. Basically either 0
to go left or 1 to go right */
gboolean next_index;
/* Next entry in the stack */
CoglAtlasStackEntry *next;
};
static CoglAtlasNode *
_cogl_atlas_node_new (void)
{
return g_slice_new (CoglAtlasNode);
}
static void
_cogl_atlas_node_free (CoglAtlasNode *node)
{
g_slice_free (CoglAtlasNode, node);
}
CoglAtlas *
_cogl_atlas_new (unsigned int width,
unsigned int height,
GDestroyNotify value_destroy_func)
{
CoglAtlas *atlas = g_new (CoglAtlas, 1);
CoglAtlasNode *root = _cogl_atlas_node_new ();
root->type = COGL_ATLAS_EMPTY_LEAF;
root->parent = NULL;
root->rectangle.x = 0;
root->rectangle.y = 0;
root->rectangle.width = width;
root->rectangle.height = height;
atlas->root = root;
atlas->space_remaining = width * height;
atlas->n_rectangles = 0;
atlas->value_destroy_func = value_destroy_func;
return atlas;
}
static CoglAtlasStackEntry *
_cogl_atlas_stack_push (CoglAtlasStackEntry *stack,
CoglAtlasNode *node,
gboolean next_index)
{
CoglAtlasStackEntry *new_entry = g_slice_new (CoglAtlasStackEntry);
new_entry->node = node;
new_entry->next_index = next_index;
new_entry->next = stack;
return new_entry;
}
static CoglAtlasStackEntry *
_cogl_atlas_stack_pop (CoglAtlasStackEntry *stack)
{
CoglAtlasStackEntry *next = stack->next;
g_slice_free (CoglAtlasStackEntry, stack);
return next;
}
static CoglAtlasNode *
_cogl_atlas_node_split_horizontally (CoglAtlasNode *node,
unsigned int left_width)
{
/* Splits the node horizontally (according to emacs' definition, not
vim) by converting it to a branch and adding two new leaf
nodes. The leftmost branch will have the width left_width and
will be returned. If the node is already just the right size it
won't do anything */
CoglAtlasNode *left_node, *right_node;
if (node->rectangle.width == left_width)
return node;
left_node = _cogl_atlas_node_new ();
left_node->type = COGL_ATLAS_EMPTY_LEAF;
left_node->parent = node;
left_node->rectangle.x = node->rectangle.x;
left_node->rectangle.y = node->rectangle.y;
left_node->rectangle.width = left_width;
left_node->rectangle.height = node->rectangle.height;
node->d.branch.left = left_node;
right_node = _cogl_atlas_node_new ();
right_node->type = COGL_ATLAS_EMPTY_LEAF;
right_node->parent = node;
right_node->rectangle.x = node->rectangle.x + left_width;
right_node->rectangle.y = node->rectangle.y;
right_node->rectangle.width = node->rectangle.width - left_width;
right_node->rectangle.height = node->rectangle.height;
node->d.branch.right = right_node;
node->type = COGL_ATLAS_BRANCH;
return left_node;
}
static CoglAtlasNode *
_cogl_atlas_node_split_vertically (CoglAtlasNode *node,
unsigned int top_height)
{
/* Splits the node vertically (according to emacs' definition, not
vim) by converting it to a branch and adding two new leaf
nodes. The topmost branch will have the height top_height and
will be returned. If the node is already just the right size it
won't do anything */
CoglAtlasNode *top_node, *bottom_node;
if (node->rectangle.height == top_height)
return node;
top_node = _cogl_atlas_node_new ();
top_node->type = COGL_ATLAS_EMPTY_LEAF;
top_node->parent = node;
top_node->rectangle.x = node->rectangle.x;
top_node->rectangle.y = node->rectangle.y;
top_node->rectangle.width = node->rectangle.width;
top_node->rectangle.height = top_height;
node->d.branch.left = top_node;
bottom_node = _cogl_atlas_node_new ();
bottom_node->type = COGL_ATLAS_EMPTY_LEAF;
bottom_node->parent = node;
bottom_node->rectangle.x = node->rectangle.x;
bottom_node->rectangle.y = node->rectangle.y + top_height;
bottom_node->rectangle.width = node->rectangle.width;
bottom_node->rectangle.height = node->rectangle.height - top_height;
node->d.branch.right = bottom_node;
node->type = COGL_ATLAS_BRANCH;
return top_node;
}
gboolean
_cogl_atlas_add_rectangle (CoglAtlas *atlas,
unsigned int width,
unsigned int height,
gpointer data,
CoglAtlasRectangle *rectangle)
{
/* Stack of nodes to search in */
CoglAtlasStackEntry *node_stack;
CoglAtlasNode *found_node = NULL;
/* Zero-sized rectangles break the algorithm for removing rectangles
so we'll disallow them */
g_return_val_if_fail (width > 0 && height > 0, FALSE);
/* Start with the root node */
node_stack = _cogl_atlas_stack_push (NULL, atlas->root, FALSE);
/* Depth-first search for an empty node that is big enough */
while (node_stack)
{
/* Pop an entry off the stack */
CoglAtlasNode *node = node_stack->node;
int next_index = node_stack->next_index;
node_stack = _cogl_atlas_stack_pop (node_stack);
/* Regardless of the type of the node, there's no point
descending any further if the new rectangle won't fit within
it */
if (node->rectangle.width >= width &&
node->rectangle.height >= height)
{
if (node->type == COGL_ATLAS_EMPTY_LEAF)
{
/* We've found a node we can use */
found_node = node;
break;
}
else if (node->type == COGL_ATLAS_BRANCH)
{
if (next_index)
/* Try the right branch */
node_stack = _cogl_atlas_stack_push (node_stack,
node->d.branch.right,
0);
else
{
/* Make sure we remember to try the right branch once
we've finished descending the left branch */
node_stack = _cogl_atlas_stack_push (node_stack,
node,
1);
/* Try the left branch */
node_stack = _cogl_atlas_stack_push (node_stack,
node->d.branch.left,
0);
}
}
}
}
/* Free the stack */
while (node_stack)
node_stack = _cogl_atlas_stack_pop (node_stack);
if (found_node)
{
/* Split according to whichever axis will leave us with the
largest space */
if (found_node->rectangle.width - width >
found_node->rectangle.height - height)
{
found_node = _cogl_atlas_node_split_horizontally (found_node, width);
found_node = _cogl_atlas_node_split_vertically (found_node, height);
}
else
{
found_node = _cogl_atlas_node_split_vertically (found_node, height);
found_node = _cogl_atlas_node_split_horizontally (found_node, width);
}
found_node->type = COGL_ATLAS_FILLED_LEAF;
found_node->d.data = data;
if (rectangle)
*rectangle = found_node->rectangle;
/* Record how much empty space is remaining after this rectangle
is added */
g_assert (width * height <= atlas->space_remaining);
atlas->space_remaining -= width * height;
atlas->n_rectangles++;
#ifdef COGL_ENABLE_DEBUG
if (G_UNLIKELY (cogl_debug_flags & COGL_DEBUG_DUMP_ATLAS_IMAGE))
_cogl_atlas_dump_image (atlas);
#endif
return TRUE;
}
else
return FALSE;
}
void
_cogl_atlas_remove_rectangle (CoglAtlas *atlas,
const CoglAtlasRectangle *rectangle)
{
CoglAtlasNode *node = atlas->root;
/* We can do a binary-chop down the search tree to find the rectangle */
while (node->type == COGL_ATLAS_BRANCH)
{
CoglAtlasNode *left_node = node->d.branch.left;
/* If and only if the rectangle is in the left node then the x,y
position of the rectangle will be within the node's
rectangle */
if (rectangle->x < left_node->rectangle.x + left_node->rectangle.width &&
rectangle->y < left_node->rectangle.y + left_node->rectangle.height)
/* Go left */
node = left_node;
else
/* Go right */
node = node->d.branch.right;
}
/* Make sure we found the right node */
if (node->type != COGL_ATLAS_FILLED_LEAF ||
node->rectangle.x != rectangle->x ||
node->rectangle.y != rectangle->y ||
node->rectangle.width != rectangle->width ||
node->rectangle.height != rectangle->height)
/* This should only happen if someone tried to remove a rectangle
that was not in the atlas so something has gone wrong */
g_return_if_reached ();
else
{
/* Convert the node back to an empty node */
if (atlas->value_destroy_func)
atlas->value_destroy_func (node->d.data);
node->type = COGL_ATLAS_EMPTY_LEAF;
/* Walk back up the tree combining branch nodes that have two
empty leaves back into a single empty leaf */
for (node = node->parent; node; node = node->parent)
{
/* This node is a parent so it should always be a branch */
g_assert (node->type == COGL_ATLAS_BRANCH);
if (node->d.branch.left->type == COGL_ATLAS_EMPTY_LEAF &&
node->d.branch.right->type == COGL_ATLAS_EMPTY_LEAF)
{
_cogl_atlas_node_free (node->d.branch.left);
_cogl_atlas_node_free (node->d.branch.right);
node->type = COGL_ATLAS_EMPTY_LEAF;
}
else
break;
}
/* There is now more free space and one less rectangle */
atlas->space_remaining += rectangle->width * rectangle->height;
g_assert (atlas->n_rectangles > 0);
atlas->n_rectangles--;
}
#ifdef COGL_ENABLE_DEBUG
if (G_UNLIKELY (cogl_debug_flags & COGL_DEBUG_DUMP_ATLAS_IMAGE))
_cogl_atlas_dump_image (atlas);
#endif
}
unsigned int
_cogl_atlas_get_width (CoglAtlas *atlas)
{
return atlas->root->rectangle.width;
}
unsigned int
_cogl_atlas_get_height (CoglAtlas *atlas)
{
return atlas->root->rectangle.height;
}
unsigned int
_cogl_atlas_get_remaining_space (CoglAtlas *atlas)
{
return atlas->space_remaining;
}
unsigned int
_cogl_atlas_get_n_rectangles (CoglAtlas *atlas)
{
return atlas->n_rectangles;
}
static void
_cogl_atlas_internal_foreach (CoglAtlas *atlas,
CoglAtlasInternalForeachCb callback,
gpointer data)
{
/* Stack of nodes to search in */
CoglAtlasStackEntry *node_stack;
/* Start with the root node */
node_stack = _cogl_atlas_stack_push (NULL, atlas->root, 0);
/* Iterate all nodes depth-first */
while (node_stack)
{
CoglAtlasNode *node = node_stack->node;
switch (node->type)
{
case COGL_ATLAS_BRANCH:
if (node_stack->next_index == 0)
{
/* Next time we come back to this node, go to the right */
node_stack->next_index = 1;
/* Explore the left branch next */
node_stack = _cogl_atlas_stack_push (node_stack,
node->d.branch.left,
0);
}
else if (node_stack->next_index == 1)
{
/* Next time we come back to this node, stop processing it */
node_stack->next_index = 2;
/* Explore the right branch next */
node_stack = _cogl_atlas_stack_push (node_stack,
node->d.branch.right,
0);
}
else
{
/* We're finished with this node so we can call the callback */
callback (node, data);
node_stack = _cogl_atlas_stack_pop (node_stack);
}
break;
default:
/* Some sort of leaf node, just call the callback */
callback (node, data);
node_stack = _cogl_atlas_stack_pop (node_stack);
break;
}
}
/* The stack should now be empty */
g_assert (node_stack == NULL);
}
typedef struct _CoglAtlasForeachClosure
{
CoglAtlasCallback callback;
gpointer data;
} CoglAtlasForeachClosure;
static void
_cogl_atlas_foreach_cb (CoglAtlasNode *node, gpointer data)
{
CoglAtlasForeachClosure *closure = data;
if (node->type == COGL_ATLAS_FILLED_LEAF)
closure->callback (&node->rectangle, node->d.data, closure->data);
}
void
_cogl_atlas_foreach (CoglAtlas *atlas,
CoglAtlasCallback callback,
gpointer data)
{
CoglAtlasForeachClosure closure;
closure.callback = callback;
closure.data = data;
_cogl_atlas_internal_foreach (atlas, _cogl_atlas_foreach_cb, &closure);
}
static void
_cogl_atlas_free_cb (CoglAtlasNode *node, gpointer data)
{
CoglAtlas *atlas = data;
if (node->type == COGL_ATLAS_FILLED_LEAF && atlas->value_destroy_func)
atlas->value_destroy_func (node->d.data);
_cogl_atlas_node_free (node);
}
void
_cogl_atlas_free (CoglAtlas *atlas)
{
_cogl_atlas_internal_foreach (atlas, _cogl_atlas_free_cb, atlas);
g_free (atlas);
}
#ifdef COGL_ENABLE_DEBUG
static void
_cogl_atlas_dump_image_cb (CoglAtlasNode *node, gpointer data)
{
cairo_t *cr = data;
if (node->type == COGL_ATLAS_FILLED_LEAF ||
node->type == COGL_ATLAS_EMPTY_LEAF)
{
/* Fill the rectangle using a different colour depending on
whether the rectangle is used */
if (node->type == COGL_ATLAS_FILLED_LEAF)
cairo_set_source_rgb (cr, 0.0, 0.0, 1.0);
else
cairo_set_source_rgb (cr, 0.0, 0.0, 0.0);
cairo_rectangle (cr,
node->rectangle.x,
node->rectangle.y,
node->rectangle.width,
node->rectangle.height);
cairo_fill_preserve (cr);
/* Draw a white outline around the rectangle */
cairo_set_source_rgb (cr, 1.0, 1.0, 1.0);
cairo_stroke (cr);
}
}
static void
_cogl_atlas_dump_image (CoglAtlas *atlas)
{
/* This dumps a png to help visualize the atlas. Each leaf rectangle
is drawn with a white outline. Unused leaves are filled in black
and used leaves are blue */
cairo_surface_t *surface =
cairo_image_surface_create (CAIRO_FORMAT_RGB24,
_cogl_atlas_get_width (atlas),
_cogl_atlas_get_height (atlas));
cairo_t *cr = cairo_create (surface);
_cogl_atlas_internal_foreach (atlas, _cogl_atlas_dump_image_cb, cr);
cairo_destroy (cr);
cairo_surface_write_to_png (surface, "cogl-atlas-dump.png");
cairo_surface_destroy (surface);
}
#endif /* COGL_ENABLE_DEBUG */