1 files changed, 94 insertions, 0 deletions
diff --git a/source/blender/bmesh/bmesh_walkers.h b/source/blender/bmesh/bmesh_walkers.h
new file mode 100644
index 00000000000..e7ab636f361
--- /dev/null
+++ b/source/blender/bmesh/bmesh_walkers.h
@@ -0,0 +1,94 @@
+#ifndef BM_WALKERS_H
+#define BM_WALKERS_H
+
+#include "BLI_ghash.h"
+
+/*
+  NOTE: do NOT modify topology while walking a mesh!
+*/
+
+typedef enum {
+	BMW_DEPTH_FIRST,
+	BMW_BREADTH_FIRST,
+} BMWOrder;
+
+/*Walkers*/
+typedef struct BMWalker {
+	void (*begin) (struct BMWalker *walker, void *start);
+	void *(*step) (struct BMWalker *walker);
+	void *(*yield)(struct BMWalker *walker);
+	int structsize;
+	BMWOrder order;
+	int flag;
+
+	BMesh *bm;
+	BLI_mempool *worklist;
+	ListBase states;
+	int restrictflag;
+	GHash *visithash;
+	int depth;
+} BMWalker;
+
+/*initialize a walker.  searchmask restricts some (not all) walkers to
+  elements with a specific tool flag set.  flags is specific to each walker.*/
+void BMW_Init(struct BMWalker *walker, BMesh *bm, int type, int searchmask, int flags);
+void *BMW_Begin(BMWalker *walker, void *start);
+void *BMW_Step(struct BMWalker *walker);
+void BMW_End(struct BMWalker *walker);
+int BMW_CurrentDepth(BMWalker *walker);
+
+/*these are used by custom walkers*/
+void *BMW_currentstate(BMWalker *walker);
+void *BMW_addstate(BMWalker *walker);
+void BMW_removestate(BMWalker *walker);
+void *BMW_walk(BMWalker *walker);
+void BMW_reset(BMWalker *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);
+f = BMW_Begin(&walker, some_start_face);
+for (; f; f=BMW_Step(&walker)) {
+	//do something with f
+}
+BMW_End(&walker);
+*/
+
+enum {
+	/*walk over connected geometry.  can restrict to a search flag,
+	or not, it's optional.
+	
+	takes a vert as an arugment, and spits out edges, restrict flag acts
+	on the edges as well.*/
+	BMW_SHELL,
+	/*walk over an edge loop.  search flag doesn't do anything.*/
+	BMW_LOOP,
+	BMW_FACELOOP,
+	BMW_EDGERING,
+	/*#define BMW_RING	2*/
+	//walk over uv islands; takes a loop as input.  restrict flag 
+	//restricts the walking to loops whose vert has restrict flag set as a
+	//tool flag.
+	//
+	//the flag parameter to BMW_Init maps to a loop customdata layer index.
+	BMW_LOOPDATA_ISLAND,
+	/*walk over an island of flagged faces.  note, that this doesn't work on
+	  non-manifold geometry.  it might be better to rewrite this to extract
+	  boundary info from the island walker, rather then directly walking
+	  over the boundary.  raises an error if it encouters nonmanifold
+	  geometry.*/
+	BMW_ISLANDBOUND,
+	/*walk over all faces in an island of tool flagged faces.*/
+	BMW_ISLAND,
+	/*walk from a vertex to all connected vertices.*/
+	BMW_CONNECTED_VERTEX,
+	/*do not intitialze function pointers and struct size in BMW_Init*/
+	BMW_CUSTOM,
+	BMW_MAXWALKERS
+};
+
+#endif