bmesh_walkers.hh

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/* SPDX-FileCopyrightText: 2023 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */
 
#pragma once
 
/*
 * NOTE: do NOT modify topology while walking a mesh!
 */
 
typedef enum {
  BMW_DEPTH_FIRST,
  BMW_BREADTH_FIRST,
} BMWOrder;
 
typedef enum {
  BMW_FLAG_NOP = 0,
  BMW_FLAG_TEST_HIDDEN = (1 << 0),
} BMWFlag;
 
/*Walkers*/
typedef struct BMWalker {
  char begin_htype; /* only for validating input */
  void (*begin)(struct BMWalker *walker, void *start);
  void *(*step)(struct BMWalker *walker);
  void *(*yield)(struct BMWalker *walker);
  int structsize;
  BMWOrder order;
  int valid_mask;
 
  /* runtime */
  int layer;
 
  BMesh *bm;
  BLI_mempool *worklist;
  ListBase states;
 
  /* these masks are to be tested against elements BMO_elem_flag_test(),
   * should never be accessed directly only through BMW_init() and bmw_mask_check_*() functions */
  short mask_vert;
  short mask_edge;
  short mask_face;
 
  BMWFlag flag;
 
  struct GSet *visit_set;
  struct GSet *visit_set_alt;
  int depth;
} BMWalker;
 
/* define to make BMW_init more clear */
#define BMW_MASK_NOP 0
 
void BMW_init(struct BMWalker *walker,
              BMesh *bm,
              int type,
              short mask_vert,
              short mask_edge,
              short mask_face,
              BMWFlag flag,
              int layer);
void *BMW_begin(BMWalker *walker, void *start);
void *BMW_step(struct BMWalker *walker);
void BMW_end(struct BMWalker *walker);
int BMW_current_depth(BMWalker *walker);
 
/* These are used by custom walkers. */
void *BMW_current_state(BMWalker *walker);
void *BMW_state_add(BMWalker *walker);
void BMW_state_remove(BMWalker *walker);
void *BMW_walk(BMWalker *walker);
void BMW_reset(BMWalker *walker);
 
#define BMW_ITER(ele, walker, data) \
  for (BM_CHECK_TYPE_ELEM_ASSIGN(ele) = BMW_begin(walker, (BM_CHECK_TYPE_ELEM(data), data)); ele; \
       BM_CHECK_TYPE_ELEM_ASSIGN(ele) = BMW_step(walker))
 
/*
 * example of usage, walking over an island of tool flagged faces:
 *
 * BMWalker walker;
 * BMFace *f;
 *
 * BMW_init(&walker, bm, BMW_ISLAND, SOME_OP_FLAG);
 *
 * for (f = BMW_begin(&walker, some_start_face); f; f = BMW_step(&walker)) {
 *     // do something with f
 * }
 * BMW_end(&walker);
 */
 
enum {
  BMW_VERT_SHELL,
  BMW_LOOP_SHELL,
  BMW_LOOP_SHELL_WIRE,
  BMW_FACE_SHELL,
  BMW_EDGELOOP,
  BMW_FACELOOP,
  BMW_EDGERING,
  BMW_EDGEBOUNDARY,
  BMW_EDGELOOP_NONMANIFOLD,
  /* BMW_RING, */
  BMW_LOOPDATA_ISLAND,
  BMW_ISLANDBOUND,
  BMW_ISLAND,
  BMW_ISLAND_MANIFOLD,
  BMW_CONNECTED_VERTEX,
  /* End of array index enum values. */
 
  /* Do not initialize function pointers and struct size in #BMW_init. */
  BMW_CUSTOM,
  BMW_MAXWALKERS,
};
 
/* use with BMW_init, so as not to confuse with restrict flags */
#define BMW_NIL_LAY 0