From 6dfe4cbc6b8717223c631e80af6c7552576966e1 Mon Sep 17 00:00:00 2001
From: Campbell Barton <ideasman42@gmail.com>
Date: Mon, 23 Oct 2017 01:15:26 +1100
Subject: [PATCH] Polyfill Beautify: half-edge optimization

Was using an edge hash for triangle -> edge lookups,
updating triangle indices for each edge-rotation.

Replace this with half-edge which can rotate edges much more simply,
writing triangles back once the solution has been calculated.

Gives ~33% speedup in own tests.
---
 .../blender/blenlib/BLI_polyfill2d_beautify.h |   3 +-
 .../blenlib/intern/polyfill2d_beautify.c      | 436 ++++++++----------
 source/blender/bmesh/intern/bmesh_polygon.c   |   9 +-
 source/blender/bmesh/intern/bmesh_polygon.h   |   3 +-
 .../bmesh/operators/bmo_connect_concave.c     |  11 +-
 .../bmesh/tools/bmesh_decimate_collapse.c     |  12 +-
 .../blender/bmesh/tools/bmesh_triangulate.c   |  15 +-
 tests/gtests/blenlib/BLI_polyfill2d_test.cc   |   5 +-
 8 files changed, 204 insertions(+), 290 deletions(-)

diff --git a/source/blender/blenlib/BLI_polyfill2d_beautify.h b/source/blender/blenlib/BLI_polyfill2d_beautify.h
index 29a900200bb..278771e9611 100644
--- a/source/blender/blenlib/BLI_polyfill2d_beautify.h
+++ b/source/blender/blenlib/BLI_polyfill2d_beautify.h
@@ -21,7 +21,6 @@
 #ifndef __BLI_POLYFILL2D_BEAUTIFY_H__
 #define __BLI_POLYFILL2D_BEAUTIFY_H__
 
-struct EdgeHash;
 struct Heap;
 struct MemArena;
 
@@ -31,7 +30,7 @@ void BLI_polyfill_beautify(
         unsigned int (*tris)[3],
 
         /* structs for reuse */
-        struct MemArena *arena, struct Heap *eheap, struct EdgeHash *eh);
+        struct MemArena *arena, struct Heap *eheap);
 
 float BLI_polyfill_beautify_quad_rotate_calc_ex(
         const float v1[2], const float v2[2], const float v3[2], const float v4[2],
diff --git a/source/blender/blenlib/intern/polyfill2d_beautify.c b/source/blender/blenlib/intern/polyfill2d_beautify.c
index 5f6fb8e6cd4..f2a1c194eb1 100644
--- a/source/blender/blenlib/intern/polyfill2d_beautify.c
+++ b/source/blender/blenlib/intern/polyfill2d_beautify.c
@@ -42,77 +42,56 @@
 #include "BLI_math.h"
 
 #include "BLI_memarena.h"
-#include "BLI_edgehash.h"
 #include "BLI_heap.h"
 
 #include "BLI_polyfill2d_beautify.h"  /* own include */
 
 #include "BLI_strict_flags.h"
 
-struct PolyEdge {
-	/** ordered vert indices (smaller first) */
-	unsigned int verts[2];
-	/** ordered face indices (depends on winding compared to the edge verts)
-	 * - (verts[0], verts[1])  == faces[0]
-	 * - (verts[1], verts[0])  == faces[1]
-	 */
-	unsigned int faces[2];
-	/**
-	 * The face-index which isn't used by either of the edges verts [0 - 2].
-	 * could be calculated each time, but cleaner to store for reuse.
-	 */
-	unsigned int faces_other_v[2];
+/* Used to find matching edges. */
+struct OrderEdge {
+	uint verts[2];
+	uint e_half;
 };
 
+/* Half edge used for rotating in-place. */
+struct HalfEdge {
+	uint v;
+	uint e_next;
+	uint e_radial;
+	uint base_index;
+};
 
-#ifndef NDEBUG
-/**
- * Only to check for error-cases.
- */
-static void polyfill_validate_tri(unsigned int (*tris)[3], unsigned int tri_index, EdgeHash *ehash)
+static int oedge_cmp(const void *a1, const void *a2)
 {
-	const unsigned int *tri = tris[tri_index];
-	int j_curr;
-
-	BLI_assert(!ELEM(tri[0], tri[1], tri[2]) &&
-	           !ELEM(tri[1], tri[0], tri[2]) &&
-	           !ELEM(tri[2], tri[0], tri[1]));
-
-	for (j_curr = 0; j_curr < 3; j_curr++) {
-		struct PolyEdge *e;
-		unsigned int e_v1 = tri[(j_curr    )    ];
-		unsigned int e_v2 = tri[(j_curr + 1) % 3];
-		e = BLI_edgehash_lookup(ehash, e_v1, e_v2);
-		if (e) {
-			if (e->faces[0] == tri_index) {
-				BLI_assert(e->verts[0] == e_v1);
-				BLI_assert(e->verts[1] == e_v2);
-			}
-			else if (e->faces[1] == tri_index) {
-				BLI_assert(e->verts[0] == e_v2);
-				BLI_assert(e->verts[1] == e_v1);
-			}
-			else {
-				BLI_assert(0);
-			}
-
-			BLI_assert(e->faces[0] != e->faces[1]);
-			BLI_assert(ELEM(e_v1, UNPACK3(tri)));
-			BLI_assert(ELEM(e_v2, UNPACK3(tri)));
-			BLI_assert(ELEM(e_v1, UNPACK2(e->verts)));
-			BLI_assert(ELEM(e_v2, UNPACK2(e->verts)));
-			BLI_assert(e_v1 != tris[e->faces[0]][e->faces_other_v[0]]);
-			BLI_assert(e_v1 != tris[e->faces[1]][e->faces_other_v[1]]);
-			BLI_assert(e_v2 != tris[e->faces[0]][e->faces_other_v[0]]);
-			BLI_assert(e_v2 != tris[e->faces[1]][e->faces_other_v[1]]);
-
-			BLI_assert(ELEM(tri_index, UNPACK2(e->faces)));
-		}
+	const struct OrderEdge *x1 = a1, *x2 = a2;
+	if (x1->verts[0] > x2->verts[0]) {
+		return 1;
+	}
+	else if (x1->verts[0] < x2->verts[0]) {
+		return -1;
 	}
-}
-#endif
 
-BLI_INLINE bool is_boundary_edge(unsigned int i_a, unsigned int i_b, const unsigned int coord_last)
+	if (x1->verts[1] > x2->verts[1]) {
+		return 1;
+	}
+	else if (x1->verts[1] < x2->verts[1]) {
+		return -1;
+	}
+
+	/* only for pradictability */
+	if (x1->e_half > x2->e_half) {
+		return 1;
+	}
+	else if (x1->e_half < x2->e_half) {
+		return -1;
+	}
+	/* Should never get here, no two edges should be the same. */
+	BLI_assert(false);
+	return 0;
+}
+
+BLI_INLINE bool is_boundary_edge(uint i_a, uint i_b, const uint coord_last)
 {
 	BLI_assert(i_a < i_b);
 	return ((i_a + 1 == i_b) || UNLIKELY((i_a == 0) && (i_b == coord_last)));
@@ -215,27 +194,31 @@ float BLI_polyfill_beautify_quad_rotate_calc_ex(
 
 static float polyedge_rotate_beauty_calc(
         const float (*coords)[2],
-        const unsigned int (*tris)[3],
-        const struct PolyEdge *e)
+        const struct HalfEdge *edges,
+        const struct HalfEdge *e_a)
 {
+	const struct HalfEdge *e_b = &edges[e_a->e_radial];
+
+	const struct HalfEdge *e_a_other = &edges[edges[e_a->e_next].e_next];
+	const struct HalfEdge *e_b_other = &edges[edges[e_b->e_next].e_next];
+
 	const float *v1, *v2, *v3, *v4;
 
-	v1 = coords[tris[e->faces[0]][e->faces_other_v[0]]];
-	v3 = coords[tris[e->faces[1]][e->faces_other_v[1]]];
-	v2 = coords[e->verts[0]];
-	v4 = coords[e->verts[1]];
+	v1 = coords[e_a_other->v];
+	v2 = coords[e_a->v];
+	v3 = coords[e_b_other->v];
+	v4 = coords[e_b->v];
 
 	return BLI_polyfill_beautify_quad_rotate_calc(v1, v2, v3, v4);
 }
 
 static void polyedge_beauty_cost_update_single(
         const float (*coords)[2],
-        const unsigned int (*tris)[3],
-        const struct PolyEdge *edges,
-        struct PolyEdge *e,
+        const struct HalfEdge *edges,
+        struct HalfEdge *e,
         Heap *eheap, HeapNode **eheap_table)
 {
-	const unsigned int i = (unsigned int)(e - edges);
+	const uint i = e->base_index;
 
 	if (eheap_table[i]) {
 		BLI_heap_remove(eheap, eheap_table[i]);
@@ -244,7 +227,7 @@ static void polyedge_beauty_cost_update_single(
 
 	{
 		/* recalculate edge */
-		const float cost = polyedge_rotate_beauty_calc(coords, tris, e);
+		const float cost = polyedge_rotate_beauty_calc(coords, edges, e);
 		/* We can get cases where both choices generate very small negative costs, which leads to infinite loop.
 		 * Anyway, costs above that are not worth recomputing, maybe we could even optimize it to a smaller limit?
 		 * Actually, FLT_EPSILON is too small in some cases, 1e-6f seems to work OK hopefully?
@@ -260,39 +243,22 @@ static void polyedge_beauty_cost_update_single(
 
 static void polyedge_beauty_cost_update(
         const float (*coords)[2],
-        const unsigned int (*tris)[3],
-        const struct PolyEdge *edges,
-        struct PolyEdge *e,
-        Heap *eheap, HeapNode **eheap_table,
-        EdgeHash *ehash)
+        struct HalfEdge *edges,
+        struct HalfEdge *e,
+        Heap *eheap, HeapNode **eheap_table)
 {
-	const unsigned int *tri_0 = tris[e->faces[0]];
-	const unsigned int *tri_1 = tris[e->faces[1]];
-	unsigned int i;
+	struct HalfEdge *e_arr[4];
+	e_arr[0] = &edges[e->e_next];
+	e_arr[1] = &edges[e_arr[0]->e_next];
 
-	struct PolyEdge *e_arr[4] = {
-		BLI_edgehash_lookup(ehash,
-		        tri_0[(e->faces_other_v[0]    ) % 3],
-		        tri_0[(e->faces_other_v[0] + 1) % 3]),
-		BLI_edgehash_lookup(ehash,
-		        tri_0[(e->faces_other_v[0] + 2) % 3],
-		        tri_0[(e->faces_other_v[0]    ) % 3]),
-		BLI_edgehash_lookup(ehash,
-		        tri_1[(e->faces_other_v[1]    ) % 3],
-		        tri_1[(e->faces_other_v[1] + 1) % 3]),
-		BLI_edgehash_lookup(ehash,
-		        tri_1[(e->faces_other_v[1] + 2) % 3],
-		        tri_1[(e->faces_other_v[1]    ) % 3]),
-	};
-
-
-	for (i = 0; i < 4; i++) {
-		if (e_arr[i]) {
-			BLI_assert(!(ELEM(e_arr[i]->faces[0], UNPACK2(e->faces)) &&
-			             ELEM(e_arr[i]->faces[1], UNPACK2(e->faces))));
+	e = &edges[e->e_radial];
+	e_arr[2] = &edges[e->e_next];
+	e_arr[3] = &edges[e_arr[2]->e_next];
 
+	for (uint i = 0; i < 4; i++) {
+		if (e_arr[i] && e_arr[i]->base_index != UINT_MAX) {
 			polyedge_beauty_cost_update_single(
-			        coords, tris, edges,
+			        coords, edges,
 			        e_arr[i],
 			        eheap, eheap_table);
 		}
@@ -300,91 +266,49 @@ static void polyedge_beauty_cost_update(
 }
 
 static void polyedge_rotate(
-        unsigned int (*tris)[3],
-        struct PolyEdge *e,
-        EdgeHash *ehash)
+        struct HalfEdge *edges,
+        struct HalfEdge *e)
 {
-	unsigned int e_v1_new = tris[e->faces[0]][e->faces_other_v[0]];
-	unsigned int e_v2_new = tris[e->faces[1]][e->faces_other_v[1]];
+	/** CCW winding, rotate internal edge to new vertical state.
+	 * <pre>
+	 *   Before         After
+	 *      X             X
+	 *     / \           /|\
+	 *  e4/   \e5     e4/ | \e5
+	 *   / e3  \       /  |  \
+	 * X ------- X -> X e0|e3 X
+	 *   \ e0  /       \  |  /
+	 *  e2\   /e1     e2\ | /e1
+	 *     \ /           \|/
+	 *      X             X
+	 * </pre>
+	 */
+	struct HalfEdge *ed[6];
+	uint ed_index[6];
 
-#ifndef NDEBUG
-	polyfill_validate_tri(tris, e->faces[0], ehash);
-	polyfill_validate_tri(tris, e->faces[1], ehash);
-#endif
+	ed_index[0] = (uint)(e - edges);
+	ed[0] = &edges[ed_index[0]];
+	ed_index[1] = ed[0]->e_next;
+	ed[1] = &edges[ed_index[1]];
+	ed_index[2] = ed[1]->e_next;
+	ed[2] = &edges[ed_index[2]];
 
-	BLI_assert(e_v1_new != e_v2_new);
-	BLI_assert(!ELEM(e_v2_new, UNPACK3(tris[e->faces[0]])));
-	BLI_assert(!ELEM(e_v1_new, UNPACK3(tris[e->faces[1]])));
+	ed_index[3] = e->e_radial;
+	ed[3] = &edges[ed_index[3]];
+	ed_index[4] = ed[3]->e_next;
+	ed[4] = &edges[ed_index[4]];
+	ed_index[5] = ed[4]->e_next;
+	ed[5] = &edges[ed_index[5]];
 
-	tris[e->faces[0]][(e->faces_other_v[0] + 1) % 3] = e_v2_new;
-	tris[e->faces[1]][(e->faces_other_v[1] + 1) % 3] = e_v1_new;
+	ed[0]->e_next = ed_index[2];
+	ed[1]->e_next = ed_index[3];
+	ed[2]->e_next = ed_index[4];
+	ed[3]->e_next = ed_index[5];
+	ed[4]->e_next = ed_index[0];
+	ed[5]->e_next = ed_index[1];
 
-	e->faces_other_v[0] = (e->faces_other_v[0] + 2) % 3;
-	e->faces_other_v[1] = (e->faces_other_v[1] + 2) % 3;
-
-	BLI_assert((tris[e->faces[0]][e->faces_other_v[0]] != e_v1_new) &&
-	           (tris[e->faces[0]][e->faces_other_v[0]] != e_v2_new));
-	BLI_assert((tris[e->faces[1]][e->faces_other_v[1]] != e_v1_new) &&
-	           (tris[e->faces[1]][e->faces_other_v[1]] != e_v2_new));
-
-	BLI_edgehash_remove(ehash, e->verts[0], e->verts[1], NULL);
-	BLI_edgehash_insert(ehash, e_v1_new, e_v2_new, e);
-
-	if (e_v1_new < e_v2_new) {
-		e->verts[0] = e_v1_new;
-		e->verts[1] = e_v2_new;
-	}
-	else {
-		/* maintain winding info */
-		e->verts[0] = e_v2_new;
-		e->verts[1] = e_v1_new;
-
-		SWAP(unsigned int, e->faces[0], e->faces[1]);
-		SWAP(unsigned int, e->faces_other_v[0], e->faces_other_v[1]);
-	}
-
-	/* update adjacent data */
-	{
-		unsigned int e_side = 0;
-
-		for (e_side = 0; e_side < 2; e_side++) {
-			/* 't_other' which we need to swap out is always the same edge-order */
-			const unsigned int t_other = (((e->faces_other_v[e_side]) + 2)) % 3;
-			unsigned int t_index = e->faces[e_side];
-			unsigned int t_index_other = e->faces[!e_side];
-			unsigned int *tri = tris[t_index];
-
-			struct PolyEdge *e_other;
-			unsigned int e_v1 = tri[(t_other    )    ];
-			unsigned int e_v2 = tri[(t_other + 1) % 3];
-
-			e_other = BLI_edgehash_lookup(ehash, e_v1, e_v2);
-			if (e_other) {
-				BLI_assert(t_index != e_other->faces[0] && t_index != e_other->faces[1]);
-				if (t_index_other == e_other->faces[0]) {
-					e_other->faces[0] = t_index;
-					e_other->faces_other_v[0] = (t_other + 2) % 3;
-					BLI_assert(!ELEM(tri[e_other->faces_other_v[0]], e_v1, e_v2));
-				}
-				else if (t_index_other == e_other->faces[1]) {
-					e_other->faces[1] = t_index;
-					e_other->faces_other_v[1] = (t_other + 2) % 3;
-					BLI_assert(!ELEM(tri[e_other->faces_other_v[1]], e_v1, e_v2));
-				}
-				else {
-					BLI_assert(0);
-				}
-			}
-		}
-	}
-
-#ifndef NDEBUG
-	polyfill_validate_tri(tris, e->faces[0], ehash);
-	polyfill_validate_tri(tris, e->faces[1], ehash);
-#endif
-
-	BLI_assert(!ELEM(tris[e->faces[0]][e->faces_other_v[0]], UNPACK2(e->verts)));
-	BLI_assert(!ELEM(tris[e->faces[1]][e->faces_other_v[1]], UNPACK2(e->verts)));
+	ed[0]->v = ed[5]->v;
+	ed[3]->v = ed[2]->v;
 }
 
 /**
@@ -397,108 +321,124 @@ static void polyedge_rotate(
  */
 void BLI_polyfill_beautify(
         const float (*coords)[2],
-        const unsigned int coords_tot,
-        unsigned int (*tris)[3],
+        const uint coords_tot,
+        uint (*tris)[3],
 
         /* structs for reuse */
-        MemArena *arena, Heap *eheap, EdgeHash *ehash)
+        MemArena *arena, Heap *eheap)
 {
-	const unsigned int coord_last = coords_tot - 1;
-	const unsigned int tris_tot = coords_tot - 2;
+	const uint coord_last = coords_tot - 1;
+	const uint tris_len = coords_tot - 2;
 	/* internal edges only (between 2 tris) */
-	const unsigned int edges_tot = tris_tot - 1;
-	unsigned int edges_tot_used = 0;
-	unsigned int i;
+	const uint edges_len = tris_len - 1;
 
 	HeapNode **eheap_table;
 
-	struct PolyEdge *edges = BLI_memarena_alloc(arena, edges_tot * sizeof(*edges));
-
-	BLI_assert(BLI_heap_size(eheap) == 0);
-	BLI_assert(BLI_edgehash_size(ehash) == 0);
+	const uint half_edges_len = 3 * tris_len;
+	struct HalfEdge *half_edges = BLI_memarena_alloc(arena, sizeof(*half_edges) * half_edges_len);
+	struct OrderEdge *order_edges = BLI_memarena_alloc(arena, sizeof(struct OrderEdge) * 2 * edges_len);
+	uint order_edges_len = 0;
 
 	/* first build edges */
-	for (i = 0; i < tris_tot; i++) {
-		unsigned int j_prev, j_curr, j_next;
-		j_prev = 2;
-		j_next = 1;
-		for (j_curr = 0; j_curr < 3; j_next = j_prev, j_prev = j_curr++) {
-			int e_index;
+	for (uint i = 0; i < tris_len; i++) {
+		for (uint j_curr = 0, j_prev = 2; j_curr < 3; j_prev = j_curr++) {
+			const uint e_index_prev = (i * 3) + j_prev;
+			const uint e_index_curr = (i * 3) + j_curr;
 
-			unsigned int e_pair[2] = {
-				tris[i][j_prev],
-				tris[i][j_curr],
-			};
+			half_edges[e_index_prev].v = tris[i][j_prev];
+			half_edges[e_index_prev].e_next = e_index_curr;
+			half_edges[e_index_prev].e_radial = UINT_MAX;
+			half_edges[e_index_prev].base_index = UINT_MAX;
 
+			uint e_pair[2] = {tris[i][j_prev], tris[i][j_curr]};
 			if (e_pair[0] > e_pair[1]) {
-				SWAP(unsigned int, e_pair[0], e_pair[1]);
-				e_index = 1;
-			}
-			else {
-				e_index = 0;
+				SWAP(uint, e_pair[0], e_pair[1]);
 			}
 
+			/* ensure internal edges. */
 			if (!is_boundary_edge(e_pair[0], e_pair[1], coord_last)) {
-				struct PolyEdge *e;
-				void **val_p;
-
-				if (!BLI_edgehash_ensure_p(ehash, e_pair[0], e_pair[1], &val_p)) {
-					e = &edges[edges_tot_used++];
-					*val_p = e;
-					memcpy(e->verts, e_pair, sizeof(e->verts));
-#ifndef NDEBUG
-					e->faces[!e_index] = (unsigned int)-1;
-#endif
-				}
-				else {
-					e = *val_p;
-					/* ensure each edge only ever has 2x users */
-#ifndef NDEBUG
-					BLI_assert(e->faces[e_index] == (unsigned int)-1);
-					BLI_assert((e->verts[0] == e_pair[0]) &&
-					           (e->verts[1] == e_pair[1]));
-#endif
-				}
-
-				e->faces[e_index] = i;
-				e->faces_other_v[e_index] = j_next;
+				order_edges[order_edges_len].verts[0] = e_pair[0];
+				order_edges[order_edges_len].verts[1] = e_pair[1];
+				order_edges[order_edges_len].e_half = e_index_prev;
+				order_edges_len += 1;
 			}
 		}
 	}
+	BLI_assert(edges_len * 2 == order_edges_len);
 
-	/* now perform iterative rotations */
-	eheap_table = BLI_memarena_alloc(arena, sizeof(HeapNode *) * (size_t)edges_tot);
+	qsort(order_edges, order_edges_len, sizeof(struct OrderEdge), oedge_cmp);
 
-	// for (i = 0; i < tris_tot; i++) { polyfill_validate_tri(tris, i, eh); }
+	for (uint i = 0, base_index = 0; i < order_edges_len; base_index++) {
+		const struct OrderEdge *oe_a = &order_edges[i++];
+		const struct OrderEdge *oe_b = &order_edges[i++];
+		BLI_assert(oe_a->verts[0] == oe_a->verts[0] && oe_a->verts[1] == oe_a->verts[1]);
+		half_edges[oe_a->e_half].e_radial = oe_b->e_half;
+		half_edges[oe_b->e_half].e_radial = oe_a->e_half;
+		half_edges[oe_a->e_half].base_index = base_index;
+		half_edges[oe_b->e_half].base_index = base_index;
+	}
+	/* order_edges could be freed now. */
 
-	/* build heap */
-	for (i = 0; i < edges_tot; i++) {
-		struct PolyEdge *e = &edges[i];
-		const float cost = polyedge_rotate_beauty_calc(coords, (const unsigned int (*)[3])tris, e);
-		if (cost < 0.0f) {
-			eheap_table[i] = BLI_heap_insert(eheap, cost, e);
-		}
-		else {
-			eheap_table[i] = NULL;
+	/* Now perform iterative rotations. */
+#if 0
+	eheap_table = BLI_memarena_alloc(arena, sizeof(HeapNode *) * (size_t)edges_len);
+#else
+	/* We can re-use this since its big enough. */
+	eheap_table = (void *)order_edges;
+	order_edges = NULL;
+#endif
+
+	/* Build heap. */
+	{
+		struct HalfEdge *e = half_edges;
+		for (uint i = 0; i < half_edges_len; i++, e++) {
+			/* Accounts for boundary edged too (UINT_MAX). */
+			if (e->e_radial < i) {
+				const float cost = polyedge_rotate_beauty_calc(coords, half_edges, e);
+				if (cost < 0.0f) {
+					eheap_table[e->base_index] = BLI_heap_insert(eheap, cost, e);
+				}
+				else {
+					eheap_table[e->base_index] = NULL;
+				}
+			}
 		}
 	}
 
 	while (BLI_heap_is_empty(eheap) == false) {
-		struct PolyEdge *e = BLI_heap_popmin(eheap);
-		i = (unsigned int)(e - edges);
-		eheap_table[i] = NULL;
+		struct HalfEdge *e = BLI_heap_popmin(eheap);
+		eheap_table[e->base_index] = NULL;
 
-		polyedge_rotate(tris, e, ehash);
+		polyedge_rotate(half_edges, e);
 
 		/* recalculate faces connected on the heap */
 		polyedge_beauty_cost_update(
-		        coords, (const unsigned int (*)[3])tris, edges,
+		        coords, half_edges,
 		        e,
-		        eheap, eheap_table, ehash);
+		        eheap, eheap_table);
 	}
 
 	BLI_heap_clear(eheap, NULL);
-	BLI_edgehash_clear_ex(ehash, NULL, BLI_POLYFILL_ALLOC_NGON_RESERVE);
 
 	/* MEM_freeN(eheap_table); */  /* arena */
+
+	/* get tris from half edge. */
+	uint tri_index = 0;
+	for (uint i = 0; i < half_edges_len; i++) {
+		struct HalfEdge *e = &half_edges[i];
+		if (e->v != UINT_MAX) {
+			uint *tri = tris[tri_index++];
+
+			tri[0] = e->v;
+			e->v = UINT_MAX;
+
+			e = &half_edges[e->e_next];
+			tri[1] = e->v;
+			e->v = UINT_MAX;
+
+			e = &half_edges[e->e_next];
+			tri[2] = e->v;
+			e->v = UINT_MAX;
+		}
+	}
 }
diff --git a/source/blender/bmesh/intern/bmesh_polygon.c b/source/blender/bmesh/intern/bmesh_polygon.c
index 977ae192c79..bf5fc18935d 100644
--- a/source/blender/bmesh/intern/bmesh_polygon.c
+++ b/source/blender/bmesh/intern/bmesh_polygon.c
@@ -925,7 +925,7 @@ void BM_face_triangulate(
         MemArena *pf_arena,
 
         /* use for MOD_TRIANGULATE_NGON_BEAUTY only! */
-        struct Heap *pf_heap, struct EdgeHash *pf_ehash)
+        struct Heap *pf_heap)
 {
 	const int cd_loop_mdisp_offset = CustomData_get_offset(&bm->ldata, CD_MDISPS);
 	const bool use_beauty = (ngon_method == MOD_TRIANGULATE_NGON_BEAUTY);
@@ -1041,7 +1041,7 @@ void BM_face_triangulate(
 			if (use_beauty) {
 				BLI_polyfill_beautify(
 				        projverts, f->len, tris,
-				        pf_arena, pf_heap, pf_ehash);
+				        pf_arena, pf_heap);
 			}
 
 			BLI_memarena_clear(pf_arena);
@@ -1497,7 +1497,6 @@ void BM_mesh_calc_tessellation_beauty(BMesh *bm, BMLoop *(*looptris)[3], int *r_
 
 	/* use_beauty */
 	Heap *pf_heap = NULL;
-	EdgeHash *pf_ehash = NULL;
 
 	BM_ITER_MESH (efa, &iter, bm, BM_FACES_OF_MESH) {
 		/* don't consider two-edged faces */
@@ -1574,7 +1573,6 @@ void BM_mesh_calc_tessellation_beauty(BMesh *bm, BMLoop *(*looptris)[3], int *r_
 			if (UNLIKELY(pf_arena == NULL)) {
 				pf_arena = BLI_memarena_new(BLI_MEMARENA_STD_BUFSIZE, __func__);
 				pf_heap = BLI_heap_new_ex(BLI_POLYFILL_ALLOC_NGON_RESERVE);
-				pf_ehash = BLI_edgehash_new_ex(__func__, BLI_POLYFILL_ALLOC_NGON_RESERVE);
 			}
 
 			tris = BLI_memarena_alloc(pf_arena, sizeof(*tris) * totfilltri);
@@ -1593,7 +1591,7 @@ void BM_mesh_calc_tessellation_beauty(BMesh *bm, BMLoop *(*looptris)[3], int *r_
 
 			BLI_polyfill_calc_arena(projverts, efa->len, 1, tris, pf_arena);
 
-			BLI_polyfill_beautify(projverts, efa->len, tris, pf_arena, pf_heap, pf_ehash);
+			BLI_polyfill_beautify(projverts, efa->len, tris, pf_arena, pf_heap);
 
 			for (j = 0; j < totfilltri; j++) {
 				BMLoop **l_ptr = looptris[i++];
@@ -1612,7 +1610,6 @@ void BM_mesh_calc_tessellation_beauty(BMesh *bm, BMLoop *(*looptris)[3], int *r_
 		BLI_memarena_free(pf_arena);
 
 		BLI_heap_free(pf_heap, NULL);
-		BLI_edgehash_free(pf_ehash, NULL);
 	}
 
 	*r_looptris_tot = i;
diff --git a/source/blender/bmesh/intern/bmesh_polygon.h b/source/blender/bmesh/intern/bmesh_polygon.h
index 313caac1243..4ec8ea59018 100644
--- a/source/blender/bmesh/intern/bmesh_polygon.h
+++ b/source/blender/bmesh/intern/bmesh_polygon.h
@@ -27,7 +27,6 @@
  *  \ingroup bmesh
  */
 
-struct EdgeHash;
 struct Heap;
 
 #include "BLI_compiler_attrs.h"
@@ -83,7 +82,7 @@ void  BM_face_triangulate(
         const int quad_method, const int ngon_method,
         const bool use_tag,
         struct MemArena *pf_arena,
-        struct Heap *pf_heap, struct EdgeHash *pf_ehash
+        struct Heap *pf_heap
         ) ATTR_NONNULL(1, 2);
 
 void  BM_face_splits_check_legal(BMesh *bm, BMFace *f, BMLoop *(*loops)[2], int len) ATTR_NONNULL();
diff --git a/source/blender/bmesh/operators/bmo_connect_concave.c b/source/blender/bmesh/operators/bmo_connect_concave.c
index 9bb67ed9341..80774323d31 100644
--- a/source/blender/bmesh/operators/bmo_connect_concave.c
+++ b/source/blender/bmesh/operators/bmo_connect_concave.c
@@ -41,7 +41,6 @@
 #include "BLI_heap.h"
 #include "BLI_polyfill2d.h"
 #include "BLI_polyfill2d_beautify.h"
-#include "BLI_edgehash.h"
 #include "BLI_linklist.h"
 
 #include "bmesh.h"
@@ -77,7 +76,7 @@ static bool bm_face_split_by_concave(
         BMesh *bm, BMFace *f_base, const float eps,
 
         MemArena *pf_arena,
-        struct Heap *pf_heap, struct EdgeHash *pf_ehash)
+        struct Heap *pf_heap)
 {
 	const int f_base_len = f_base->len;
 	int faces_array_tot = f_base_len - 3;
@@ -99,7 +98,7 @@ static bool bm_face_split_by_concave(
 	        &faces_double,
 	        quad_method, ngon_method, false,
 	        pf_arena,
-	        pf_heap, pf_ehash);
+	        pf_heap);
 
 	BLI_assert(edges_array_tot <= f_base_len - 3);
 
@@ -161,7 +160,6 @@ static bool bm_face_split_by_concave(
 	}
 
 	BLI_heap_clear(pf_heap, NULL);
-	BLI_edgehash_clear_ex(pf_ehash, NULL, BLI_POLYFILL_ALLOC_NGON_RESERVE);
 
 	while (faces_double) {
 		LinkNode *next = faces_double->next;
@@ -201,17 +199,15 @@ void bmo_connect_verts_concave_exec(BMesh *bm, BMOperator *op)
 
 	MemArena *pf_arena;
 	Heap *pf_heap;
-	EdgeHash *pf_ehash;
 
 	pf_arena = BLI_memarena_new(BLI_POLYFILL_ARENA_SIZE, __func__);
 	pf_heap = BLI_heap_new_ex(BLI_POLYFILL_ALLOC_NGON_RESERVE);
-	pf_ehash = BLI_edgehash_new_ex(__func__, BLI_POLYFILL_ALLOC_NGON_RESERVE);
 
 	BMO_ITER (f, &siter, op->slots_in, "faces", BM_FACE) {
 		if (f->len > 3 && bm_face_convex_tag_verts(f)) {
 			if (bm_face_split_by_concave(
 			        bm, f, FLT_EPSILON,
-			        pf_arena, pf_heap, pf_ehash))
+			        pf_arena, pf_heap))
 			{
 				changed = true;
 			}
@@ -225,5 +221,4 @@ void bmo_connect_verts_concave_exec(BMesh *bm, BMOperator *op)
 
 	BLI_memarena_free(pf_arena);
 	BLI_heap_free(pf_heap, NULL);
-	BLI_edgehash_free(pf_ehash, NULL);
 }
diff --git a/source/blender/bmesh/tools/bmesh_decimate_collapse.c b/source/blender/bmesh/tools/bmesh_decimate_collapse.c
index 36ae7231f94..d734d9b6ae1 100644
--- a/source/blender/bmesh/tools/bmesh_decimate_collapse.c
+++ b/source/blender/bmesh/tools/bmesh_decimate_collapse.c
@@ -497,7 +497,7 @@ static bool bm_face_triangulate(
 
         MemArena *pf_arena,
         /* use for MOD_TRIANGULATE_NGON_BEAUTY only! */
-        struct Heap *pf_heap, struct EdgeHash *pf_ehash)
+        struct Heap *pf_heap)
 {
 	const int f_base_len = f_base->len;
 	int faces_array_tot = f_base_len - 3;
@@ -516,8 +516,7 @@ static bool bm_face_triangulate(
 	        edges_array, &edges_array_tot,
 	        r_faces_double,
 	        quad_method, ngon_method, false,
-	        pf_arena,
-	        pf_heap, pf_ehash);
+	        pf_arena, pf_heap);
 
 	for (int i = 0; i < edges_array_tot; i++) {
 		BMLoop *l_iter, *l_first;
@@ -567,19 +566,16 @@ static bool bm_decim_triangulate_begin(BMesh *bm, int *r_edges_tri_tot)
 	{
 		MemArena *pf_arena;
 		Heap *pf_heap;
-		EdgeHash *pf_ehash;
 
 		LinkNode *faces_double = NULL;
 
 		if (has_ngon) {
 			pf_arena = BLI_memarena_new(BLI_POLYFILL_ARENA_SIZE, __func__);
 			pf_heap = BLI_heap_new_ex(BLI_POLYFILL_ALLOC_NGON_RESERVE);
-			pf_ehash = BLI_edgehash_new_ex(__func__, BLI_POLYFILL_ALLOC_NGON_RESERVE);
 		}
 		else {
 			pf_arena = NULL;
 			pf_heap = NULL;
-			pf_ehash = NULL;
 		}
 
 		/* adding new faces as we loop over faces
@@ -591,8 +587,7 @@ static bool bm_decim_triangulate_begin(BMesh *bm, int *r_edges_tri_tot)
 				        bm, f, &faces_double,
 				        r_edges_tri_tot,
 
-				        pf_arena,
-				        pf_heap, pf_ehash);
+				        pf_arena, pf_heap);
 			}
 		}
 
@@ -606,7 +601,6 @@ static bool bm_decim_triangulate_begin(BMesh *bm, int *r_edges_tri_tot)
 		if (has_ngon) {
 			BLI_memarena_free(pf_arena);
 			BLI_heap_free(pf_heap, NULL);
-			BLI_edgehash_free(pf_ehash, NULL);
 		}
 
 		BLI_assert((bm->elem_index_dirty & BM_VERT) == 0);
diff --git a/source/blender/bmesh/tools/bmesh_triangulate.c b/source/blender/bmesh/tools/bmesh_triangulate.c
index ce1bc46d5e8..bd201fa89bf 100644
--- a/source/blender/bmesh/tools/bmesh_triangulate.c
+++ b/source/blender/bmesh/tools/bmesh_triangulate.c
@@ -35,7 +35,6 @@
 #include "BLI_alloca.h"
 #include "BLI_memarena.h"
 #include "BLI_heap.h"
-#include "BLI_edgehash.h"
 #include "BLI_linklist.h"
 
 /* only for defines */
@@ -57,7 +56,7 @@ static void bm_face_triangulate_mapping(
 
         MemArena *pf_arena,
         /* use for MOD_TRIANGULATE_NGON_BEAUTY only! */
-        struct Heap *pf_heap, struct EdgeHash *pf_ehash)
+        struct Heap *pf_heap)
 {
 	int faces_array_tot = face->len - 3;
 	BMFace  **faces_array = BLI_array_alloca(faces_array, faces_array_tot);
@@ -71,7 +70,7 @@ static void bm_face_triangulate_mapping(
 	        &faces_double,
 	        quad_method, ngon_method, use_tag,
 	        pf_arena,
-	        pf_heap, pf_ehash);
+	        pf_heap);
 
 	if (faces_array_tot) {
 		int i;
@@ -98,17 +97,14 @@ void BM_mesh_triangulate(
 	BMFace *face;
 	MemArena *pf_arena;
 	Heap *pf_heap;
-	EdgeHash *pf_ehash;
 
 	pf_arena = BLI_memarena_new(BLI_POLYFILL_ARENA_SIZE, __func__);
 
 	if (ngon_method == MOD_TRIANGULATE_NGON_BEAUTY) {
 		pf_heap = BLI_heap_new_ex(BLI_POLYFILL_ALLOC_NGON_RESERVE);
-		pf_ehash = BLI_edgehash_new_ex(__func__, BLI_POLYFILL_ALLOC_NGON_RESERVE);
 	}
 	else {
 		pf_heap = NULL;
-		pf_ehash = NULL;
 	}
 
 	if (slot_facemap_out) {
@@ -120,8 +116,7 @@ void BM_mesh_triangulate(
 					        bm, face,
 					        quad_method, ngon_method, tag_only,
 					        op, slot_facemap_out, slot_facemap_double_out,
-					        pf_arena,
-					        pf_heap, pf_ehash);
+					        pf_arena, pf_heap);
 				}
 			}
 		}
@@ -138,8 +133,7 @@ void BM_mesh_triangulate(
 					        NULL, NULL,
 					        &faces_double,
 					        quad_method, ngon_method, tag_only,
-					        pf_arena,
-					        pf_heap, pf_ehash);
+					        pf_arena, pf_heap);
 				}
 			}
 		}
@@ -156,6 +150,5 @@ void BM_mesh_triangulate(
 
 	if (ngon_method == MOD_TRIANGULATE_NGON_BEAUTY) {
 		BLI_heap_free(pf_heap, NULL);
-		BLI_edgehash_free(pf_ehash, NULL);
 	}
 }
diff --git a/tests/gtests/blenlib/BLI_polyfill2d_test.cc b/tests/gtests/blenlib/BLI_polyfill2d_test.cc
index df98ead4cb9..235bae3e5ff 100644
--- a/tests/gtests/blenlib/BLI_polyfill2d_test.cc
+++ b/tests/gtests/blenlib/BLI_polyfill2d_test.cc
@@ -13,7 +13,6 @@ extern "C" {
 #include "BLI_array_utils.h"
 #include "BLI_polyfill2d.h"
 #include "BLI_math.h"
-#include "BLI_edgehash.h"
 #include "MEM_guardedalloc.h"
 
 #ifdef USE_OBJ_PREVIEW
@@ -195,17 +194,15 @@ static void test_polyfill_template(
 	{
 		MemArena *pf_arena = BLI_memarena_new(BLI_POLYFILL_ARENA_SIZE, __func__);
 		Heap *pf_heap = BLI_heap_new_ex(BLI_POLYFILL_ALLOC_NGON_RESERVE);
-		EdgeHash *pf_ehash = BLI_edgehash_new_ex(__func__, BLI_POLYFILL_ALLOC_NGON_RESERVE);
 
 		BLI_polyfill_beautify(
 		        poly, poly_tot, tris,
-		        pf_arena, pf_heap, pf_ehash);
+		        pf_arena, pf_heap);
 
 		test_polyfill_template_check(id, is_degenerate, poly, poly_tot, tris, tris_tot);
 
 		BLI_memarena_free(pf_arena);
 		BLI_heap_free(pf_heap, NULL);
-		BLI_edgehash_free(pf_ehash, NULL);
 	}
 #endif
 }