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tested & debugged on two cases (both heuristics); unknown if BF is *correct*.

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master
Sean Barrett ago%!(EXTRA string=11 years)
parent b09f8186dc
commit 0c10e7c40e
1 changed files with 102 additions and 31 deletions
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  1. 133
      stb_rect_pack.h

133
stb_rect_pack.h
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@ -30,17 +30,26 @@ typedef struct stbrp_context stbrp_context;
typedef struct stbrp_node stbrp_node;
typedef struct stbrp_rect stbrp_rect;
enum
{
STBRP_HEURISTIC_Skyline_default=0,
STBRP_HEURISTIC_Skyline_BL_sortHeight = STBRP_HEURISTIC_Skyline_default,
STBRP_HEURISTIC_Skyline_BF_sortHeight,
};
#ifdef STBRP_LARGE_RECTS
typedef int stbrp_coord;
#else
typedef unsigned short stbrp_coord;
#endif
STBRP_DEF void stbrp_init_packer (stbrp_context *context, int width, int height, stbrp_node *nodes, int num_nodes);
STBRP_DEF void stbrp_allow_oom (stbrp_context *context, int allow_out_of_mem);
STBRP_DEF void stbrp_set_heuristic(stbrp_context *context, int heuristic);
STBRP_DEF void stbrp_pack_rects (stbrp_context *context, stbrp_rect *rects, int num_rects);
STBRP_DEF void stbrp_pack_rects (stbrp_context *context, stbrp_rect *rects, int num_rects);
// Assign packing locations to rectangles. The rectangles are of type
// 'stbrp_rect' defined below, stored in the array 'rects', and there
// are 'num_rects' many of them.
//
// Rectangles which are successfully packed have the 'was_packed' flag
// set to a non-zero value and 'x' and 'y' store the minimum location
// on each axis (i.e. bottom-left in cartesian coordinates, top-left
// if you imagine y increasing downwards). Rectangles which do not fit
// have the 'was_packed' flag set to 0.
//
// You should not try to access the 'rects' array from another thread
// while this function is running, as the function temporarily reorders
// the array while it executes.
struct stbrp_rect
{
@ -48,19 +57,52 @@ struct stbrp_rect
int id;
// input:
unsigned short w, h;
stbrp_coord w, h;
// output:
unsigned short x, y;
stbrp_coord x, y;
int was_packed; // non-zero if valid packing
}; // 16 bytes, nominally
STBRP_DEF void stbrp_init_packer (stbrp_context *context, int width, int height, stbrp_node *nodes, int num_nodes);
// Initialize a rectangle packer to:
// pack a rectangle that is 'width' by 'height' in dimensions
// using temporary storage provided by the array 'nodes', which is 'num_nodes' long
//
// Note: to guarantee best results, either:
// 1. make sure 'num_nodes' >= 'width'
// or 2. call stbrp_allow_out_of_mem() defined below with 'allow_out_of_mem = 1'
//
// If you don't do either of the above things, widths will be quantized to multiples
// of small integers to guarantee the algorithm doesn't run out of temporary storage.
//
// If you do #2, then the non-quantized algorithm will be used, but the algorithm
// may run out of temporary storage and be unable to pack some rectangles.
STBRP_DEF void stbrp_setup_allow_out_of_mem (stbrp_context *context, int allow_out_of_mem);
// Optionally call this function after init but before doing any packing to
// change the handling of the out-of-temp-memory scenario, described above.
STBRP_DEF void stbrp_setup_heuristic (stbrp_context *context, int heuristic);
// Optionally select which packing heuristic the library should use. Different
// heuristics will produce better/worse results for different data sets.
enum
{
STBRP_HEURISTIC_Skyline_default=0,
STBRP_HEURISTIC_Skyline_BL_sortHeight = STBRP_HEURISTIC_Skyline_default,
STBRP_HEURISTIC_Skyline_BF_sortHeight,
};
// the details of the following structures don't matter to you, but they must
// be visible so you can manage the memory allocations for them
// be visible so you can handle the memory allocations for them
struct stbrp_node
{
unsigned short x,y;
stbrp_node *next;
stbrp_coord x,y;
stbrp_node *next;
};
struct stbrp_context
@ -73,7 +115,7 @@ struct stbrp_context
int num_nodes;
stbrp_node *active_head;
stbrp_node *free_head;
stbrp_node extra[2]; // we allocate two extra nodes so user only needs to create 'width' for correctness, not width+1
stbrp_node extra[2]; // we allocate two extra nodes so optimal user-node-count is 'width' not 'width+2'
};
#ifdef __cplusplus
@ -92,7 +134,7 @@ enum
STBRP__INIT_skyline = 1,
};
STBRP_DEF void stbrp_set_heuristic(stbrp_context *context, int heuristic)
STBRP_DEF void stbrp_setup_heuristic(stbrp_context *context, int heuristic)
{
switch (context->init_mode) {
case STBRP__INIT_skyline:
@ -103,7 +145,7 @@ STBRP_DEF void stbrp_set_heuristic(stbrp_context *context, int heuristic)
}
}
STBRP_DEF void stbrp_allow_oom(stbrp_context *context, int allow_out_of_mem)
STBRP_DEF void stbrp_setup_allow_out_of_mem(stbrp_context *context, int allow_out_of_mem)
{
if (allow_out_of_mem)
// if it's ok to run out of memory, then don't bother aligning them;
@ -126,6 +168,10 @@ STBRP_DEF void stbrp_allow_oom(stbrp_context *context, int allow_out_of_mem)
STBRP_DEF void stbrp_init_packer(stbrp_context *context, int width, int height, stbrp_node *nodes, int num_nodes)
{
int i;
#ifndef STBRP_LARGE_RECTS
assert(width <= 0xffff && height <= 0xffff);
#endif
for (i=0; i < num_nodes-1; ++i)
nodes[i].next = &nodes[i+1];
nodes[i].next = NULL;
@ -134,16 +180,21 @@ STBRP_DEF void stbrp_init_packer(stbrp_context *context, int width, int height,
context->free_head = &nodes[0];
context->active_head = &context->extra[0];
context->width = width;
context->height = height;
context->num_nodes = num_nodes;
stbrp_allow_oom(context, 0);
stbrp_setup_allow_out_of_mem(context, 0);
// node 0 is the full width, node 1 is the sentinel (lets us not store width explicitly)
context->extra[0].x = 0;
context->extra[0].y = 0;
context->extra[0].next = &context->extra[1];
context->extra[1].x = width;
#ifdef STBRP_LARGE_RECTS
context->extra[1].y = (1<<30);
#else
context->extra[1].y = 65535;
context->extra[2].next = NULL;
#endif
context->extra[1].next = NULL;
}
// find minimum y position if it starts at x1
@ -171,7 +222,7 @@ static int stbrp__skyline_find_min_y(stbrp_context *c, stbrp_node *first, int x0
if (node->y > min_y) {
// raise min_y higher.
// we've accounted for all waste up to min_y,
// but we'll now ad more waste for everything we've visted
// but we'll now add more waste for everything we've visted
waste_area += visited_width * (node->y - min_y);
min_y = node->y;
} else {
@ -195,11 +246,9 @@ typedef struct
stbrp_node **prev_link;
} stbrp__findresult;
#define STBRP__HUGE_Y (1<<30)
static stbrp__findresult stbrp__skyline_find_best_pos(stbrp_context *c, int width, int height)
{
int best_waste = (1<<30), best_x, best_y = STBRP__HUGE_Y;
int best_waste = (1<<30), best_x, best_y = (1 << 30);
stbrp__findresult fr;
stbrp_node **prev, *node, *tail, **best = NULL;
@ -283,7 +332,7 @@ static stbrp__findresult stbrp__skyline_find_best_pos(stbrp_context *c, int widt
}
}
fr.prev_link = prev;
fr.prev_link = best;
fr.x = best_x;
fr.y = best_y;
return fr;
@ -325,17 +374,17 @@ static stbrp__findresult stbrp__skyline_pack_rectangle(stbrp_context *context, i
*res.prev_link = node;
}
// from here, traverse cur and free nodes, until we get to one
// from here, traverse cur and free the nodes, until we get to one
// that shouldn't be freed
while (cur->next->x <= res.x + width) {
stbrp_node *next = cur->next;
// move the current node to the free list
cur->next = context->free_head;
context->free_head = cur->next;
context->free_head = cur;
cur = next;
}
// stich the list back in
// stitch the list back in
node->next = cur;
if (cur->x < res.x + width)
@ -348,6 +397,24 @@ static stbrp__findresult stbrp__skyline_pack_rectangle(stbrp_context *context, i
cur = cur->next;
}
assert(cur->next == NULL);
{
stbrp_node *L1 = NULL, *L2 = NULL;
int count=0;
cur = context->active_head;
while (cur) {
L1 = cur;
cur = cur->next;
++count;
}
cur = context->free_head;
while (cur) {
L2 = cur;
cur = cur->next;
++count;
}
assert(count == context->num_nodes+2);
}
#endif
return res;
@ -376,8 +443,12 @@ STBRP_DEF void stbrp_pack_rects(stbrp_context *context, stbrp_rect *rects, int n
int i;
// we use the 'was_packed' field internally to allow sorting/unsorting
for (i=0; i < num_rects; ++i)
for (i=0; i < num_rects; ++i) {
rects[i].was_packed = i;
#ifndef STBRP_LARGE_RECTS
assert(rects[i].w <= 0xffff && rects[i].h <= 0xffff);
#endif
}
// sort according to heuristic
qsort(rects, num_rects, sizeof(rects[0]), rect_height_compare);
@ -385,8 +456,8 @@ STBRP_DEF void stbrp_pack_rects(stbrp_context *context, stbrp_rect *rects, int n
for (i=0; i < num_rects; ++i) {
stbrp__findresult fr = stbrp__skyline_pack_rectangle(context, rects[i].w, rects[i].h);
if (fr.prev_link) {
rects[i].x = (unsigned short) fr.x;
rects[i].y = (unsigned short) fr.y;
rects[i].x = (stbrp_coord) fr.x;
rects[i].y = (stbrp_coord) fr.y;
} else {
rects[i].x = rects[i].y = 0xffff;
}

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