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Diffstat (limited to 'external/include/stb_rect_pack.h')
| -rw-r--r-- | external/include/stb_rect_pack.h | 583 |
1 files changed, 583 insertions, 0 deletions
diff --git a/external/include/stb_rect_pack.h b/external/include/stb_rect_pack.h new file mode 100644 index 0000000..c75527d --- /dev/null +++ b/external/include/stb_rect_pack.h @@ -0,0 +1,583 @@ +// 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 |