| @ -0,0 +1,546 @@ | |||
| // stb_rect_pack.h - v0.05 - 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. | |||
| // | |||
| // 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. | |||
| // | |||
| // Version history: | |||
| // | |||
| // 0.05: added STBRP_ASSERT to allow replacing assert | |||
| // 0.04: fixed minor bug in STBRP_LARGE_RECTS support | |||
| // 0.01: initial release | |||
| ////////////////////////////////////////////////////////////////////////////// | |||
| // | |||
| // 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 | |||
| #include <stdlib.h> | |||
| #ifndef STBRP_ASSERT | |||
| #include <assert.h> | |||
| #define STBRP_ASSERT assert | |||
| #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_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) | |||
| { | |||
| stbrp_rect *p = (stbrp_rect *) a; | |||
| stbrp_rect *q = (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) | |||
| { | |||
| stbrp_rect *p = (stbrp_rect *) a; | |||
| stbrp_rect *q = (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) | |||
| { | |||
| stbrp_rect *p = (stbrp_rect *) a; | |||
| stbrp_rect *q = (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 | |||
| qsort(rects, num_rects, sizeof(rects[0]), rect_height_compare); | |||
| 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 = (stbrp_coord) fr.x; | |||
| rects[i].y = (stbrp_coord) fr.y; | |||
| } else { | |||
| rects[i].x = rects[i].y = STBRP__MAXVAL; | |||
| } | |||
| } | |||
| // unsort | |||
| qsort(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 | |||