--- /dev/null
+// stb_rect_pack.h - v0.10 - public domain - rectangle packing
+// Sean Barrett 2014
+//
+// Useful for e.g. packing rectangular textures into an atlas.
+// Does not do rotation.
+//
+// Not necessarily the awesomest packing method, but better than
+// the totally naive one in stb_truetype (which is primarily what
+// this is meant to replace).
+//
+// Has only had a few tests run, may have issues.
+//
+// More docs to come.
+//
+// No memory allocations; uses qsort() and assert() from stdlib.
+// Can override those by defining STBRP_SORT and STBRP_ASSERT.
+//
+// This library currently uses the Skyline Bottom-Left algorithm.
+//
+// Please note: better rectangle packers are welcome! Please
+// implement them to the same API, but with a different init
+// function.
+//
+// Credits
+//
+// Library
+// Sean Barrett
+// Minor features
+// Martins Mozeiko
+// Bugfixes / warning fixes
+// Jeremy Jaussaud
+//
+// Version history:
+//
+// 0.10 (2016-10-25) remove cast-away-const to avoid warnings
+// 0.09 (2016-08-27) fix compiler warnings
+// 0.08 (2015-09-13) really fix bug with empty rects (w=0 or h=0)
+// 0.07 (2015-09-13) fix bug with empty rects (w=0 or h=0)
+// 0.06 (2015-04-15) added STBRP_SORT to allow replacing qsort
+// 0.05: added STBRP_ASSERT to allow replacing assert
+// 0.04: fixed minor bug in STBRP_LARGE_RECTS support
+// 0.01: initial release
+//
+// LICENSE
+//
+// This software is dual-licensed to the public domain and under the following
+// license: you are granted a perpetual, irrevocable license to copy, modify,
+// publish, and distribute this file as you see fit.
+
+//////////////////////////////////////////////////////////////////////////////
+//
+// INCLUDE SECTION
+//
+
+#ifndef STB_INCLUDE_STB_RECT_PACK_H
+#define STB_INCLUDE_STB_RECT_PACK_H
+
+#define STB_RECT_PACK_VERSION 1
+
+#ifdef STBRP_STATIC
+#define STBRP_DEF static
+#else
+#define STBRP_DEF extern
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct stbrp_context stbrp_context;
+typedef struct stbrp_node stbrp_node;
+typedef struct stbrp_rect stbrp_rect;
+
+#ifdef STBRP_LARGE_RECTS
+typedef int stbrp_coord;
+#else
+typedef unsigned short stbrp_coord;
+#endif
+
+STBRP_DEF void stbrp_pack_rects (stbrp_context *context, stbrp_rect *rects, int num_rects);
+// Assign packed 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.
+//
+// To pack into another rectangle, you need to call stbrp_init_target
+// again. To continue packing into the same rectangle, you can call
+// this function again. Calling this multiple times with multiple rect
+// arrays will probably produce worse packing results than calling it
+// a single time with the full rectangle array, but the option is
+// available.
+
+struct stbrp_rect
+{
+ // reserved for your use:
+ int id;
+
+ // input:
+ stbrp_coord w, h;
+
+ // output:
+ stbrp_coord x, y;
+ int was_packed; // non-zero if valid packing
+
+}; // 16 bytes, nominally
+
+
+STBRP_DEF void stbrp_init_target (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
+//
+// You must call this function every time you start packing into a new target.
+//
+// There is no "shutdown" function. The 'nodes' memory must stay valid for
+// the following stbrp_pack_rects() call (or calls), but can be freed after
+// the call (or calls) finish.
+//
+// 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.
+// If you call init again, this will be reset to the default (false).
+
+
+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.
+// If you call init again, this will be reset to the default.
+
+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 handle the memory allocations for them
+
+struct stbrp_node
+{
+ stbrp_coord x,y;
+ stbrp_node *next;
+};
+
+struct stbrp_context
+{
+ int width;
+ int height;
+ int align;
+ int init_mode;
+ int heuristic;
+ int num_nodes;
+ stbrp_node *active_head;
+ stbrp_node *free_head;
+ stbrp_node extra[2]; // we allocate two extra nodes so optimal user-node-count is 'width' not 'width+2'
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+
+//////////////////////////////////////////////////////////////////////////////
+//
+// IMPLEMENTATION SECTION
+//
+
+#ifdef STB_RECT_PACK_IMPLEMENTATION
+#ifndef STBRP_SORT
+#include <stdlib.h>
+#define STBRP_SORT qsort
+#endif
+
+#ifndef STBRP_ASSERT
+#include <assert.h>
+#define STBRP_ASSERT assert
+#endif
+
+#ifdef _MSC_VER
+#define STBRP__NOTUSED(v) (void)(v)
+#else
+#define STBRP__NOTUSED(v) (void)sizeof(v)
+#endif
+
+enum
+{
+ STBRP__INIT_skyline = 1
+};
+
+STBRP_DEF void stbrp_setup_heuristic(stbrp_context *context, int heuristic)
+{
+ switch (context->init_mode) {
+ case STBRP__INIT_skyline:
+ STBRP_ASSERT(heuristic == STBRP_HEURISTIC_Skyline_BL_sortHeight || heuristic == STBRP_HEURISTIC_Skyline_BF_sortHeight);
+ context->heuristic = heuristic;
+ break;
+ default:
+ STBRP_ASSERT(0);
+ }
+}
+
+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;
+ // this gives better packing, but may fail due to OOM (even though
+ // the rectangles easily fit). @TODO a smarter approach would be to only
+ // quantize once we've hit OOM, then we could get rid of this parameter.
+ context->align = 1;
+ else {
+ // if it's not ok to run out of memory, then quantize the widths
+ // so that num_nodes is always enough nodes.
+ //
+ // I.e. num_nodes * align >= width
+ // align >= width / num_nodes
+ // align = ceil(width/num_nodes)
+
+ context->align = (context->width + context->num_nodes-1) / context->num_nodes;
+ }
+}
+
+STBRP_DEF void stbrp_init_target(stbrp_context *context, int width, int height, stbrp_node *nodes, int num_nodes)
+{
+ int i;
+#ifndef STBRP_LARGE_RECTS
+ STBRP_ASSERT(width <= 0xffff && height <= 0xffff);
+#endif
+
+ for (i=0; i < num_nodes-1; ++i)
+ nodes[i].next = &nodes[i+1];
+ nodes[i].next = NULL;
+ context->init_mode = STBRP__INIT_skyline;
+ context->heuristic = STBRP_HEURISTIC_Skyline_default;
+ context->free_head = &nodes[0];
+ context->active_head = &context->extra[0];
+ context->width = width;
+ context->height = height;
+ context->num_nodes = num_nodes;
+ 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 = (stbrp_coord) width;
+#ifdef STBRP_LARGE_RECTS
+ context->extra[1].y = (1<<30);
+#else
+ context->extra[1].y = 65535;
+#endif
+ context->extra[1].next = NULL;
+}
+
+// find minimum y position if it starts at x1
+static int stbrp__skyline_find_min_y(stbrp_context *c, stbrp_node *first, int x0, int width, int *pwaste)
+{
+ stbrp_node *node = first;
+ int x1 = x0 + width;
+ int min_y, visited_width, waste_area;
+
+ STBRP__NOTUSED(c);
+
+ STBRP_ASSERT(first->x <= x0);
+
+ #if 0
+ // skip in case we're past the node
+ while (node->next->x <= x0)
+ ++node;
+ #else
+ STBRP_ASSERT(node->next->x > x0); // we ended up handling this in the caller for efficiency
+ #endif
+
+ STBRP_ASSERT(node->x <= x0);
+
+ min_y = 0;
+ waste_area = 0;
+ visited_width = 0;
+ while (node->x < x1) {
+ if (node->y > min_y) {
+ // raise min_y higher.
+ // we've accounted for all waste up to min_y,
+ // but we'll now add more waste for everything we've visted
+ waste_area += visited_width * (node->y - min_y);
+ min_y = node->y;
+ // the first time through, visited_width might be reduced
+ if (node->x < x0)
+ visited_width += node->next->x - x0;
+ else
+ visited_width += node->next->x - node->x;
+ } else {
+ // add waste area
+ int under_width = node->next->x - node->x;
+ if (under_width + visited_width > width)
+ under_width = width - visited_width;
+ waste_area += under_width * (min_y - node->y);
+ visited_width += under_width;
+ }
+ node = node->next;
+ }
+
+ *pwaste = waste_area;
+ return min_y;
+}
+
+typedef struct
+{
+ int x,y;
+ stbrp_node **prev_link;
+} stbrp__findresult;
+
+static stbrp__findresult stbrp__skyline_find_best_pos(stbrp_context *c, int width, int height)
+{
+ int best_waste = (1<<30), best_x, best_y = (1 << 30);
+ stbrp__findresult fr;
+ stbrp_node **prev, *node, *tail, **best = NULL;
+
+ // align to multiple of c->align
+ width = (width + c->align - 1);
+ width -= width % c->align;
+ STBRP_ASSERT(width % c->align == 0);
+
+ node = c->active_head;
+ prev = &c->active_head;
+ while (node->x + width <= c->width) {
+ int y,waste;
+ y = stbrp__skyline_find_min_y(c, node, node->x, width, &waste);
+ if (c->heuristic == STBRP_HEURISTIC_Skyline_BL_sortHeight) { // actually just want to test BL
+ // bottom left
+ if (y < best_y) {
+ best_y = y;
+ best = prev;
+ }
+ } else {
+ // best-fit
+ if (y + height <= c->height) {
+ // can only use it if it first vertically
+ if (y < best_y || (y == best_y && waste < best_waste)) {
+ best_y = y;
+ best_waste = waste;
+ best = prev;
+ }
+ }
+ }
+ prev = &node->next;
+ node = node->next;
+ }
+
+ best_x = (best == NULL) ? 0 : (*best)->x;
+
+ // if doing best-fit (BF), we also have to try aligning right edge to each node position
+ //
+ // e.g, if fitting
+ //
+ // ____________________
+ // |____________________|
+ //
+ // into
+ //
+ // | |
+ // | ____________|
+ // |____________|
+ //
+ // then right-aligned reduces waste, but bottom-left BL is always chooses left-aligned
+ //
+ // This makes BF take about 2x the time
+
+ if (c->heuristic == STBRP_HEURISTIC_Skyline_BF_sortHeight) {
+ tail = c->active_head;
+ node = c->active_head;
+ prev = &c->active_head;
+ // find first node that's admissible
+ while (tail->x < width)
+ tail = tail->next;
+ while (tail) {
+ int xpos = tail->x - width;
+ int y,waste;
+ STBRP_ASSERT(xpos >= 0);
+ // find the left position that matches this
+ while (node->next->x <= xpos) {
+ prev = &node->next;
+ node = node->next;
+ }
+ STBRP_ASSERT(node->next->x > xpos && node->x <= xpos);
+ y = stbrp__skyline_find_min_y(c, node, xpos, width, &waste);
+ if (y + height < c->height) {
+ if (y <= best_y) {
+ if (y < best_y || waste < best_waste || (waste==best_waste && xpos < best_x)) {
+ best_x = xpos;
+ STBRP_ASSERT(y <= best_y);
+ best_y = y;
+ best_waste = waste;
+ best = prev;
+ }
+ }
+ }
+ tail = tail->next;
+ }
+ }
+
+ fr.prev_link = best;
+ fr.x = best_x;
+ fr.y = best_y;
+ return fr;
+}
+
+static stbrp__findresult stbrp__skyline_pack_rectangle(stbrp_context *context, int width, int height)
+{
+ // find best position according to heuristic
+ stbrp__findresult res = stbrp__skyline_find_best_pos(context, width, height);
+ stbrp_node *node, *cur;
+
+ // bail if:
+ // 1. it failed
+ // 2. the best node doesn't fit (we don't always check this)
+ // 3. we're out of memory
+ if (res.prev_link == NULL || res.y + height > context->height || context->free_head == NULL) {
+ res.prev_link = NULL;
+ return res;
+ }
+
+ // on success, create new node
+ node = context->free_head;
+ node->x = (stbrp_coord) res.x;
+ node->y = (stbrp_coord) (res.y + height);
+
+ context->free_head = node->next;
+
+ // insert the new node into the right starting point, and
+ // let 'cur' point to the remaining nodes needing to be
+ // stiched back in
+
+ cur = *res.prev_link;
+ if (cur->x < res.x) {
+ // preserve the existing one, so start testing with the next one
+ stbrp_node *next = cur->next;
+ cur->next = node;
+ cur = next;
+ } else {
+ *res.prev_link = node;
+ }
+
+ // from here, traverse cur and free the nodes, until we get to one
+ // that shouldn't be freed
+ while (cur->next && 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;
+ cur = next;
+ }
+
+ // stitch the list back in
+ node->next = cur;
+
+ if (cur->x < res.x + width)
+ cur->x = (stbrp_coord) (res.x + width);
+
+#ifdef _DEBUG
+ cur = context->active_head;
+ while (cur->x < context->width) {
+ STBRP_ASSERT(cur->x < cur->next->x);
+ cur = cur->next;
+ }
+ STBRP_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;
+ }
+ STBRP_ASSERT(count == context->num_nodes+2);
+ }
+#endif
+
+ return res;
+}
+
+static int rect_height_compare(const void *a, const void *b)
+{
+ const stbrp_rect *p = (const stbrp_rect *) a;
+ const stbrp_rect *q = (const stbrp_rect *) b;
+ if (p->h > q->h)
+ return -1;
+ if (p->h < q->h)
+ return 1;
+ return (p->w > q->w) ? -1 : (p->w < q->w);
+}
+
+static int rect_width_compare(const void *a, const void *b)
+{
+ const stbrp_rect *p = (const stbrp_rect *) a;
+ const stbrp_rect *q = (const stbrp_rect *) b;
+ if (p->w > q->w)
+ return -1;
+ if (p->w < q->w)
+ return 1;
+ return (p->h > q->h) ? -1 : (p->h < q->h);
+}
+
+static int rect_original_order(const void *a, const void *b)
+{
+ const stbrp_rect *p = (const stbrp_rect *) a;
+ const stbrp_rect *q = (const stbrp_rect *) b;
+ return (p->was_packed < q->was_packed) ? -1 : (p->was_packed > q->was_packed);
+}
+
+#ifdef STBRP_LARGE_RECTS
+#define STBRP__MAXVAL 0xffffffff
+#else
+#define STBRP__MAXVAL 0xffff
+#endif
+
+STBRP_DEF void stbrp_pack_rects(stbrp_context *context, stbrp_rect *rects, int num_rects)
+{
+ int i;
+
+ // we use the 'was_packed' field internally to allow sorting/unsorting
+ for (i=0; i < num_rects; ++i) {
+ rects[i].was_packed = i;
+ #ifndef STBRP_LARGE_RECTS
+ STBRP_ASSERT(rects[i].w <= 0xffff && rects[i].h <= 0xffff);
+ #endif
+ }
+
+ // sort according to heuristic
+ STBRP_SORT(rects, num_rects, sizeof(rects[0]), rect_height_compare);
+
+ for (i=0; i < num_rects; ++i) {
+ if (rects[i].w == 0 || rects[i].h == 0) {
+ rects[i].x = rects[i].y = 0; // empty rect needs no space
+ } else {
+ stbrp__findresult fr = stbrp__skyline_pack_rectangle(context, rects[i].w, rects[i].h);
+ if (fr.prev_link) {
+ rects[i].x = (stbrp_coord) fr.x;
+ rects[i].y = (stbrp_coord) fr.y;
+ } else {
+ rects[i].x = rects[i].y = STBRP__MAXVAL;
+ }
+ }
+ }
+
+ // unsort
+ STBRP_SORT(rects, num_rects, sizeof(rects[0]), rect_original_order);
+
+ // set was_packed flags
+ for (i=0; i < num_rects; ++i)
+ rects[i].was_packed = !(rects[i].x == STBRP__MAXVAL && rects[i].y == STBRP__MAXVAL);
+}
+#endif
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