Tool System: use preselect highlight w/ poly-build

- Poly build now uses a new gizmo for pre-selection
  which has the same behavior as loop-cut.

  This replaces hack where mouse-move set the active element
  which was no longer working properly because of missing
  depsgraph updates.

- Multi-object support for poly-build.

- Support for deformed cage.

- Fix error where changing active object wasn't properly
  refreshing the preselect gizmo (for loopcut too).

Currently holding Alt to select non-boundary element's isn't working.

5 files changed, 575 insertions, 187 deletions

diff --git a/source/blender/editors/mesh/CMakeLists.txt b/source/blender/editors/mesh/CMakeLists.txt
index 4784f07c297..43360af9e18 100644
--- a/source/blender/editors/mesh/CMakeLists.txt
+++ b/source/blender/editors/mesh/CMakeLists.txt
@@ -58,6 +58,7 @@ set(SRC
 	editmesh_path.c
 	editmesh_polybuild.c
 	editmesh_preselect.c
+	editmesh_preselect_elem.c
 	editmesh_rip.c
 	editmesh_rip_edge.c
 	editmesh_select.c
diff --git a/source/blender/editors/mesh/editmesh_polybuild.c b/source/blender/editors/mesh/editmesh_polybuild.c
index 9b7d460973a..adf5802cdcf 100644
--- a/source/blender/editors/mesh/editmesh_polybuild.c
+++ b/source/blender/editors/mesh/editmesh_polybuild.c
@@ -25,6 +25,8 @@
  * an experimental tool for quickly constructing/manipulating faces.
  */
 
+#include "MEM_guardedalloc.h"
+
 #include "DNA_object_types.h"
 
 #include "BLI_math.h"
@@ -33,10 +35,13 @@
 #include "BKE_report.h"
 #include "BKE_editmesh.h"
 #include "BKE_mesh.h"
+#include "BKE_layer.h"
 
 #include "WM_types.h"
 
+#include "ED_object.h"
 #include "ED_mesh.h"
+#include "ED_scene.h"
 #include "ED_screen.h"
 #include "ED_transform.h"
 #include "ED_view3d.h"
@@ -50,6 +55,8 @@
 
 #include "WM_api.h"
 
+#include "DEG_depsgraph.h"
+
 /* -------------------------------------------------------------------- */
 /** \name Local Utilities
  * \{ */
@@ -63,6 +70,98 @@ static void edbm_selectmode_ensure(Scene *scene, BMEditMesh *em, short selectmod
 	}
 }
 
+/* Could make public, for now just keep here. */
+static void edbm_flag_disable_all_multi(ViewLayer *view_layer, const char hflag)
+{
+	uint objects_len = 0;
+	Object **objects = BKE_view_layer_array_from_objects_in_edit_mode_unique_data(view_layer, &objects_len);
+	for (uint ob_index = 0; ob_index < objects_len; ob_index++) {
+		Object *ob_iter = objects[ob_index];
+		BMEditMesh *em_iter = BKE_editmesh_from_object(ob_iter);
+		BMesh *bm_iter = em_iter->bm;
+		if (bm_iter->totvertsel) {
+			EDBM_flag_disable_all(em_iter, hflag);
+			if (hflag & BM_ELEM_SELECT) {
+				BM_select_history_clear(em_iter->bm);
+			}
+			DEG_id_tag_update(ob_iter->data, DEG_TAG_SELECT_UPDATE);
+		}
+	}
+	MEM_freeN(objects);
+}
+
+/* When accessed as a tool, get the active edge from the preselection gizmo. */
+static bool edbm_preselect_or_active(
+        bContext *C,
+        Base **r_base,
+        BMElem **r_ele)
+{
+	ViewLayer *view_layer = CTX_data_view_layer(C);
+	ARegion *ar = CTX_wm_region(C);
+	wmGizmoMap *gzmap = ar->gizmo_map;
+	wmGizmoGroup *gzgroup = gzmap ? WM_gizmomap_group_find(gzmap, "VIEW3D_GGT_mesh_preselect_elem") : NULL;
+	if (gzgroup != NULL) {
+		wmGizmo *gz = gzgroup->gizmos.first;
+		const int object_index = RNA_int_get(gz->ptr, "object_index");
+
+		/* weak, allocate an array just to access the index. */
+		Base *base = NULL;
+		Object *obedit = NULL;
+		{
+			uint bases_len;
+			Base **bases = BKE_view_layer_array_from_bases_in_edit_mode(view_layer, &bases_len);
+			if (object_index < bases_len) {
+				base = bases[object_index];
+				obedit = base->object;
+			}
+			MEM_freeN(bases);
+		}
+
+		*r_base = base;
+		*r_ele = NULL;
+
+		if (obedit) {
+			BMEditMesh *em = BKE_editmesh_from_object(obedit);
+			BMesh *bm = em->bm;
+			const int vert_index = RNA_int_get(gz->ptr, "vert_index");
+			const int edge_index = RNA_int_get(gz->ptr, "edge_index");
+			const int face_index = RNA_int_get(gz->ptr, "face_index");
+			if (vert_index != -1) {
+				*r_ele = (BMElem *)BM_vert_at_index_find(bm, vert_index);
+			}
+			else if (edge_index != -1) {
+				*r_ele = (BMElem *)BM_edge_at_index_find(bm, edge_index);
+			}
+			else if (face_index != -1) {
+				*r_ele = (BMElem *)BM_face_at_index_find(bm, face_index);
+			}
+		}
+	}
+	else {
+		Base *base = view_layer->basact;
+		Object *obedit = base->object;
+		BMEditMesh *em = BKE_editmesh_from_object(obedit);
+		BMesh *bm = em->bm;
+		*r_base = base;
+		*r_ele = BM_mesh_active_elem_get(bm);
+	}
+	return (*r_ele != NULL);
+}
+
+static bool edbm_preselect_or_active_init_viewcontext(
+        bContext *C,
+        ViewContext *vc,
+        Base **r_base,
+        BMElem **r_ele)
+{
+	em_setup_viewcontext(C, vc);
+	bool ok = edbm_preselect_or_active(C, r_base, r_ele);
+	if (ok) {
+		ED_view3d_viewcontext_init_object(vc, (*r_base)->object);
+	}
+	return ok;
+}
+
 /** \} */
 
 /* -------------------------------------------------------------------- */
@@ -72,15 +171,15 @@ static void edbm_selectmode_ensure(Scene *scene, BMEditMesh *em, short selectmod
 static int edbm_polybuild_face_at_cursor_invoke(
         bContext *C, wmOperator *UNUSED(op), const wmEvent *event)
 {
-	ViewContext vc;
 	float center[3];
 	bool changed = false;
 
-	em_setup_viewcontext(C, &vc);
-	Object *obedit = CTX_data_edit_object(C);
-	BMEditMesh *em = BKE_editmesh_from_object(obedit);
+	ViewContext vc;
+	Base *basact = NULL;
+	BMElem *ele_act = NULL;
+	edbm_preselect_or_active_init_viewcontext(C, &vc, &basact, &ele_act);
+	BMEditMesh *em = vc.em;
 	BMesh *bm = em->bm;
-	BMElem *ele_act = BM_mesh_active_elem_get(bm);
 
 	invert_m4_m4(vc.obedit->imat, vc.obedit->obmat);
 	ED_view3d_init_mats_rv3d(vc.obedit, vc.rv3d);
@@ -95,7 +194,7 @@ static int edbm_polybuild_face_at_cursor_invoke(
 		mul_m4_v3(vc.obedit->imat, center);
 
 		BMVert *v_new = BM_vert_create(bm, center, NULL, BM_CREATE_NOP);
-		EDBM_flag_disable_all(em, BM_ELEM_SELECT);
+		edbm_flag_disable_all_multi(vc.view_layer, BM_ELEM_SELECT);
 		BM_vert_select_set(bm, v_new, true);
 		changed = true;
 	}
@@ -118,7 +217,7 @@ static int edbm_polybuild_face_at_cursor_invoke(
 		// BMFace *f_new =
 		BM_face_create_verts(bm, v_tri, 3, f_reference, BM_CREATE_NOP, true);
 
-		EDBM_flag_disable_all(em, BM_ELEM_SELECT);
+		edbm_flag_disable_all_multi(vc.view_layer, BM_ELEM_SELECT);
 		BM_vert_select_set(bm, v_tri[2], true);
 		changed = true;
 	}
@@ -169,7 +268,7 @@ static int edbm_polybuild_face_at_cursor_invoke(
 			// BMFace *f_new =
 			BM_face_create_verts(bm, v_quad, 4, f_reference, BM_CREATE_NOP, true);
 
-			EDBM_flag_disable_all(em, BM_ELEM_SELECT);
+			edbm_flag_disable_all_multi(vc.view_layer, BM_ELEM_SELECT);
 			BM_vert_select_set(bm, v_quad[2], true);
 			changed = true;
 		}
@@ -188,11 +287,13 @@ static int edbm_polybuild_face_at_cursor_invoke(
 	}
 
 	if (changed) {
-		BM_select_history_clear(bm);
-
 		EDBM_mesh_normals_update(em);
 		EDBM_update_generic(em, true, true);
 
+		if (vc.view_layer->basact != basact) {
+			ED_object_base_activate(C, basact);
+		}
+
 		WM_event_add_mousemove(C);
 
 		return OPERATOR_FINISHED;
@@ -229,13 +330,14 @@ void MESH_OT_polybuild_face_at_cursor(wmOperatorType *ot)
 static int edbm_polybuild_split_at_cursor_invoke(
         bContext *C, wmOperator *UNUSED(op), const wmEvent *event)
 {
-	ViewContext vc;
 	float center[3];
 	bool changed = false;
 
-	em_setup_viewcontext(C, &vc);
-	Object *obedit = CTX_data_edit_object(C);
-	BMEditMesh *em = BKE_editmesh_from_object(obedit);
+	ViewContext vc;
+	Base *basact = NULL;
+	BMElem *ele_act = NULL;
+	edbm_preselect_or_active_init_viewcontext(C, &vc, &basact, &ele_act);
+	BMEditMesh *em = vc.em;
 	BMesh *bm = em->bm;
 
 	invert_m4_m4(vc.obedit->imat, vc.obedit->obmat);
@@ -243,8 +345,6 @@ static int edbm_polybuild_split_at_cursor_invoke(
 
 	edbm_selectmode_ensure(vc.scene, vc.em, SCE_SELECT_VERTEX);
 
-	BMElem *ele_act = BM_mesh_active_elem_get(bm);
-
 	if (ele_act == NULL || ele_act->head.hflag == BM_FACE) {
 		return OPERATOR_PASS_THROUGH;
 	}
@@ -259,7 +359,7 @@ static int edbm_polybuild_split_at_cursor_invoke(
 		BMVert *v_new = BM_edge_split(bm, e_act, e_act->v1, NULL, CLAMPIS(fac, 0.0f, 1.0f));
 		copy_v3_v3(v_new->co, center);
 
-		EDBM_flag_disable_all(em, BM_ELEM_SELECT);
+		edbm_flag_disable_all_multi(vc.view_layer, BM_ELEM_SELECT);
 		BM_vert_select_set(bm, v_new, true);
 		changed = true;
 	}
@@ -269,13 +369,15 @@ static int edbm_polybuild_split_at_cursor_invoke(
 	}
 
 	if (changed) {
-		BM_select_history_clear(bm);
-
 		EDBM_mesh_normals_update(em);
 		EDBM_update_generic(em, true, true);
 
 		WM_event_add_mousemove(C);
 
+		if (vc.view_layer->basact != basact) {
+			ED_object_base_activate(C, basact);
+		}
+
 		return OPERATOR_FINISHED;
 	}
 	else {
@@ -312,23 +414,19 @@ void MESH_OT_polybuild_split_at_cursor(wmOperatorType *ot)
 static int edbm_polybuild_dissolve_at_cursor_invoke(
         bContext *C, wmOperator *op, const wmEvent *UNUSED(event))
 {
-	ViewContext vc;
-	em_setup_viewcontext(C, &vc);
 	bool changed = false;
 
-	Object *obedit = CTX_data_edit_object(C);
-	BMEditMesh *em = BKE_editmesh_from_object(obedit);
+	ViewContext vc;
+	Base *basact = NULL;
+	BMElem *ele_act = NULL;
+	edbm_preselect_or_active_init_viewcontext(C, &vc, &basact, &ele_act);
+	BMEditMesh *em = vc.em;
 	BMesh *bm = em->bm;
-	BMVert *v_act = BM_mesh_active_vert_get(bm);
-	BMEdge *e_act = BM_mesh_active_edge_get(bm);
-
-	invert_m4_m4(vc.obedit->imat, vc.obedit->obmat);
-	ED_view3d_init_mats_rv3d(vc.obedit, vc.rv3d);
 
 	edbm_selectmode_ensure(vc.scene, vc.em, SCE_SELECT_VERTEX);
 
-
-	if (e_act) {
+	if (ele_act->head.htype == BM_EDGE) {
+		BMEdge *e_act = (BMEdge *)ele_act;
 		BMLoop *l_a, *l_b;
 		if (BM_edge_loop_pair(e_act, &l_a, &l_b)) {
 			BMFace *f_new = BM_faces_join_pair(bm, l_a, l_b, true);
@@ -337,7 +435,8 @@ static int edbm_polybuild_dissolve_at_cursor_invoke(
 			}
 		}
 	}
-	else if (v_act) {
+	else if (ele_act->head.htype == BM_VERT) {
+		BMVert *v_act = (BMVert *)ele_act;
 		if (BM_vert_is_edge_pair(v_act)) {
 			BM_edge_collapse(
 			        bm, v_act->e, v_act,
@@ -356,13 +455,15 @@ static int edbm_polybuild_dissolve_at_cursor_invoke(
 	}
 
 	if (changed) {
-		EDBM_flag_disable_all(em, BM_ELEM_SELECT);
-
-		BM_select_history_clear(bm);
+		edbm_flag_disable_all_multi(vc.view_layer, BM_ELEM_SELECT);
 
 		EDBM_mesh_normals_update(em);
 		EDBM_update_generic(em, true, true);
 
+		if (vc.view_layer->basact != basact) {
+			ED_object_base_activate(C, basact);
+		}
+
 		WM_event_add_mousemove(C);
 
 		return OPERATOR_FINISHED;
@@ -388,155 +489,3 @@ void MESH_OT_polybuild_dissolve_at_cursor(wmOperatorType *ot)
 }
 
 /** \} */
-
-/* -------------------------------------------------------------------- */
-/** \name Cursor Gizmo
- *
- * \note This may need its own file, for now not.
- * \{ */
-
-static BMElem *edbm_hover_preselect(
-        bContext *C,
-        const int mval[2],
-        bool use_boundary)
-{
-	ViewContext vc;
-
-	em_setup_viewcontext(C, &vc);
-	Object *obedit = CTX_data_edit_object(C);
-	BMEditMesh *em = BKE_editmesh_from_object(obedit);
-	BMesh *bm = em->bm;
-
-	invert_m4_m4(vc.obedit->imat, vc.obedit->obmat);
-	ED_view3d_init_mats_rv3d(vc.obedit, vc.rv3d);
-
-	const float mval_fl[2] = {UNPACK2(mval)};
-	float ray_origin[3], ray_direction[3];
-
-	BMElem *ele_best = NULL;
-
-	if (ED_view3d_win_to_ray(
-	        CTX_data_depsgraph(C),
-	        vc.ar, vc.v3d, mval_fl,
-	        ray_origin, ray_direction, true))
-	{
-		BMEdge *e;
-
-		BMIter eiter;
-		float dist_sq_best = FLT_MAX;
-
-		BM_ITER_MESH (e, &eiter, bm, BM_EDGES_OF_MESH) {
-			if ((BM_elem_flag_test(e, BM_ELEM_HIDDEN) == false) &&
-			    (!use_boundary || BM_edge_is_boundary(e)))
-			{
-				float dist_sq_test;
-				float point[3];
-				float depth;
-#if 0
-				dist_sq_test = dist_squared_ray_to_seg_v3(
-				        ray_origin, ray_direction,
-				        e->v1->co,  e->v2->co,
-				        point, &depth);
-#else
-				mid_v3_v3v3(point, e->v1->co,  e->v2->co);
-				dist_sq_test = dist_squared_to_ray_v3(
-				        ray_origin, ray_direction,
-				        point, &depth);
-#endif
-
-				if (dist_sq_test < dist_sq_best) {
-					dist_sq_best = dist_sq_test;
-					ele_best = (BMElem *)e;
-				}
-
-				dist_sq_test = dist_squared_to_ray_v3(
-				        ray_origin, ray_direction,
-				        e->v1->co, &depth);
-				if (dist_sq_test < dist_sq_best) {
-					dist_sq_best = dist_sq_test;
-					ele_best = (BMElem *)e->v1;
-				}
-				dist_sq_test = dist_squared_to_ray_v3(
-				        ray_origin, ray_direction,
-				        e->v2->co, &depth);
-				if (dist_sq_test < dist_sq_best) {
-					dist_sq_best = dist_sq_test;
-					ele_best = (BMElem *)e->v2;
-				}
-			}
-		}
-	}
-	return ele_best;
-}
-
-/*
- * Developer note: this is not advocating pre-selection highlighting.
- * This is just a quick way to test how a tool for interactively editing polygons may work. */
-static int edbm_polybuild_hover_invoke(
-        bContext *C, wmOperator *op, const wmEvent *event)
-{
-	const bool use_boundary = RNA_boolean_get(op->ptr, "use_boundary");
-	ViewContext vc;
-
-	em_setup_viewcontext(C, &vc);
-
-	/* Vertex selection is needed */
-	if ((vc.scene->toolsettings->selectmode & SCE_SELECT_VERTEX) == 0) {
-		return OPERATOR_PASS_THROUGH;
-	}
-
-	/* Don't overwrite click-drag events. */
-	if (use_boundary == false) {
-		/* pass */
-	}
-	else if (vc.win->tweak ||
-	         (vc.win->eventstate->check_click &&
-	          vc.win->eventstate->prevval == KM_PRESS &&
-	          ISMOUSE(vc.win->eventstate->prevtype)))
-	{
-		return OPERATOR_PASS_THROUGH;
-	}
-
-	Object *obedit = CTX_data_edit_object(C);
-	BMEditMesh *em = BKE_editmesh_from_object(obedit);
-	BMesh *bm = em->bm;
-	BMElem *ele_active = BM_mesh_active_elem_get(bm);
-	BMElem *ele_hover = edbm_hover_preselect(C, event->mval, use_boundary);
-
-	if (ele_hover && (ele_hover != ele_active)) {
-		if (event->shift == 0) {
-			EDBM_flag_disable_all(em, BM_ELEM_SELECT);
-			BM_select_history_clear(bm);
-		}
-		BM_elem_select_set(bm, ele_hover, true);
-		BM_select_history_store(em->bm, ele_hover);
-		BKE_mesh_batch_cache_dirty_tag(obedit->data, BKE_MESH_BATCH_DIRTY_SELECT);
-
-		ED_region_tag_redraw(vc.ar);
-
-		return OPERATOR_FINISHED;
-	}
-	else {
-		return OPERATOR_CANCELLED;
-	}
-}
-
-void MESH_OT_polybuild_hover(wmOperatorType *ot)
-{
-	/* identifiers */
-	ot->name = "Poly Build Hover";
-	ot->idname = "MESH_OT_polybuild_hover";
-	ot->description = "";
-
-	/* api callbacks */
-	ot->invoke = edbm_polybuild_hover_invoke;
-	ot->poll = EDBM_view3d_poll;
-
-	/* flags */
-	ot->flag = OPTYPE_INTERNAL;
-
-	/* properties */
-	RNA_def_boolean(ot->srna, "use_boundary", false, "Boundary", "Select only boundary geometry");
-}
-
-/** \} */
diff --git a/source/blender/editors/mesh/editmesh_preselect_elem.c b/source/blender/editors/mesh/editmesh_preselect_elem.c
new file mode 100644
index 00000000000..e0b06019de1
--- /dev/null
+++ b/source/blender/editors/mesh/editmesh_preselect_elem.c
@@ -0,0 +1,218 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/editors/mesh/editmesh_preselect_elem.c
+ *  \ingroup edmesh
+ */
+
+#include "MEM_guardedalloc.h"
+
+#include "BLI_stack.h"
+#include "BLI_math.h"
+
+#include "BKE_context.h"
+#include "BKE_editmesh.h"
+
+#include "GPU_immediate.h"
+#include "GPU_matrix.h"
+#include "GPU_state.h"
+
+#include "DNA_object_types.h"
+
+#include "ED_mesh.h"
+#include "ED_view3d.h"
+
+/* -------------------------------------------------------------------- */
+/** \name Mesh Element Pre-Select
+ * Public API:
+ *
+ * #EDBM_preselect_elem_create
+ * #EDBM_preselect_elem_destroy
+ * #EDBM_preselect_elem_clear
+ * #EDBM_preselect_elem_draw
+ * #EDBM_preselect_elem_update_from_single
+ *
+ * \{ */
+
+static void vcos_get(BMVert *v, float r_co[3], const float (*coords)[3])
+{
+	if (coords) {
+		copy_v3_v3(r_co, coords[BM_elem_index_get(v)]);
+	}
+	else {
+		copy_v3_v3(r_co, v->co);
+	}
+}
+
+static void vcos_get_pair(BMVert *v[2], float r_cos[2][3], const float (*coords)[3])
+{
+	if (coords) {
+		for (int j = 0; j < 2; j++) {
+			copy_v3_v3(r_cos[j], coords[BM_elem_index_get(v[j])]);
+		}
+	}
+	else {
+		for (int j = 0; j < 2; j++) {
+			copy_v3_v3(r_cos[j], v[j]->co);
+		}
+	}
+}
+
+struct EditMesh_PreSelElem {
+	float (*edges)[2][3];
+	int     edges_len;
+
+	float (*verts)[3];
+	int     verts_len;
+};
+
+struct EditMesh_PreSelElem *EDBM_preselect_elem_create(void)
+{
+	struct EditMesh_PreSelElem *psel = MEM_callocN(sizeof(*psel), __func__);
+	return psel;
+}
+
+void EDBM_preselect_elem_destroy(
+        struct EditMesh_PreSelElem *psel)
+{
+	EDBM_preselect_elem_clear(psel);
+	MEM_freeN(psel);
+}
+
+void EDBM_preselect_elem_clear(
+        struct EditMesh_PreSelElem *psel)
+{
+	MEM_SAFE_FREE(psel->edges);
+	psel->edges_len = 0;
+
+	MEM_SAFE_FREE(psel->verts);
+	psel->verts_len = 0;
+}
+
+void EDBM_preselect_elem_draw(
+        struct EditMesh_PreSelElem *psel, const float matrix[4][4])
+{
+	if ((psel->edges_len == 0) && (psel->verts_len == 0)) {
+		return;
+	}
+
+	GPU_depth_test(false);
+
+	GPU_matrix_push();
+	GPU_matrix_mul(matrix);
+
+	uint pos = GPU_vertformat_attr_add(immVertexFormat(), "pos", GPU_COMP_F32, 3, GPU_FETCH_FLOAT);
+
+	immBindBuiltinProgram(GPU_SHADER_3D_UNIFORM_COLOR);
+	immUniformColor3ub(255, 0, 255);
+
+	if (psel->edges_len > 0) {
+		immBegin(GPU_PRIM_LINES, psel->edges_len * 2);
+
+		for (int i = 0; i < psel->edges_len; i++) {
+			immVertex3fv(pos, psel->edges[i][0]);
+			immVertex3fv(pos, psel->edges[i][1]);
+		}
+
+		immEnd();
+	}
+
+	if (psel->verts_len > 0) {
+		GPU_point_size(3.0f);
+
+		immBegin(GPU_PRIM_POINTS, psel->verts_len);
+
+		for (int i = 0; i < psel->verts_len; i++) {
+			immVertex3fv(pos, psel->verts[i]);
+		}
+
+		immEnd();
+	}
+
+	immUnbindProgram();
+
+	GPU_matrix_pop();
+
+	/* Reset default */
+	GPU_depth_test(true);
+}
+
+static void view3d_preselect_mesh_elem_update_from_vert(
+        struct EditMesh_PreSelElem *psel,
+        BMesh *UNUSED(bm), BMVert *eve, const float (*coords)[3])
+{
+	float (*verts)[3] = MEM_mallocN(sizeof(*psel->verts), __func__);
+	vcos_get(eve, verts[0], coords);
+	psel->verts = verts;
+	psel->verts_len = 1;
+}
+
+static void view3d_preselect_mesh_elem_update_from_edge(
+        struct EditMesh_PreSelElem *psel,
+        BMesh *UNUSED(bm), BMEdge *eed, const float (*coords)[3])
+{
+	float (*edges)[2][3] = MEM_mallocN(sizeof(*psel->edges), __func__);
+	vcos_get_pair(&eed->v1, edges[0], coords);
+	psel->edges = edges;
+	psel->edges_len = 1;
+}
+
+static void view3d_preselect_mesh_elem_update_from_face(
+        struct EditMesh_PreSelElem *psel,
+        BMesh *UNUSED(bm), BMFace *efa, const float (*coords)[3])
+{
+	float (*edges)[2][3] = MEM_mallocN(sizeof(*psel->edges) * efa->len, __func__);
+	BMLoop *l_iter, *l_first;
+	l_iter = l_first = BM_FACE_FIRST_LOOP(efa);
+	int i = 0;
+	do {
+		vcos_get_pair(&l_iter->e->v1, edges[i++], coords);
+	} while ((l_iter = l_iter->next) != l_first);
+	psel->edges = edges;
+	psel->edges_len = efa->len;
+}
+
+void EDBM_preselect_elem_update_from_single(
+        struct EditMesh_PreSelElem *psel,
+        BMesh *bm, BMElem *ele,
+        const float (*coords)[3])
+{
+	EDBM_preselect_elem_clear(psel);
+
+	if (coords) {
+		BM_mesh_elem_index_ensure(bm, BM_VERT);
+	}
+
+	switch (ele->head.htype) {
+		case BM_VERT:
+			view3d_preselect_mesh_elem_update_from_vert(psel, bm, (BMVert *)ele, coords);
+			break;
+		case BM_EDGE:
+			view3d_preselect_mesh_elem_update_from_edge(psel, bm, (BMEdge *)ele, coords);
+			break;
+		case BM_FACE:
+			view3d_preselect_mesh_elem_update_from_face(psel, bm, (BMFace *)ele, coords);
+			break;
+		default:
+			BLI_assert(0);
+	}
+}
+
+/** \} */
diff --git a/source/blender/editors/mesh/editmesh_select.c b/source/blender/editors/mesh/editmesh_select.c
index df8c095e7bd..86a1366bda3 100644
--- a/source/blender/editors/mesh/editmesh_select.c
+++ b/source/blender/editors/mesh/editmesh_select.c
@@ -1098,6 +1098,227 @@ bool EDBM_unified_findnearest(
 /** \} */
 
 /* -------------------------------------------------------------------- */
+/** \name Alternate Find Nearest Vert/Edge (optional boundary)
+ *
+ * \note This uses ray-cast method instead of backbuffer,
+ * currently used for poly-build.
+ * \{ */
+
+bool EDBM_unified_findnearest_from_raycast(
+        ViewContext *vc,
+        bool use_boundary,
+        Base **r_base,
+        struct BMVert **r_eve,
+        struct BMEdge **r_eed,
+        struct BMFace **r_efa)
+{
+
+	const float mval_fl[2] = {UNPACK2(vc->mval)};
+	float ray_origin[3], ray_direction[3];
+
+	struct {
+		Base *base;
+		BMElem *ele;
+	} best = {NULL};
+
+	if (ED_view3d_win_to_ray(
+	        vc->depsgraph,
+	        vc->ar, vc->v3d, mval_fl,
+	        ray_origin, ray_direction, true))
+	{
+		float dist_sq_best = FLT_MAX;
+
+		const bool use_vert = (r_eve != NULL);
+		const bool use_edge = (r_eed != NULL);
+		const bool use_face = (r_efa != NULL);
+
+		uint bases_len;
+		Base **bases = BKE_view_layer_array_from_bases_in_edit_mode(vc->view_layer, &bases_len);
+		for (uint base_index = 0; base_index < bases_len; base_index++) {
+			Base *base_iter = bases[base_index];
+			Object *obedit = base_iter->object;
+
+			BMEditMesh *em = BKE_editmesh_from_object(obedit);
+			BMesh *bm = em->bm;
+			float imat3[3][3];
+
+			ED_view3d_viewcontext_init_object(vc, obedit);
+			copy_m3_m4(imat3, obedit->obmat);
+			invert_m3(imat3);
+
+			const float (*coords)[3] = NULL;
+			{
+				Mesh *me_eval = (Mesh *)DEG_get_evaluated_id(vc->depsgraph, obedit->data);
+				if (me_eval->runtime.edit_data) {
+					coords = me_eval->runtime.edit_data->vertexCos;
+				}
+			}
+
+			if (coords != NULL) {
+				BM_mesh_elem_index_ensure(bm, BM_VERT);
+			}
+
+			if (use_boundary && (use_vert || use_edge)) {
+				BMEdge *e;
+				BMIter eiter;
+				BM_ITER_MESH (e, &eiter, bm, BM_EDGES_OF_MESH) {
+					if ((BM_elem_flag_test(e, BM_ELEM_HIDDEN) == false) &&
+					    (BM_edge_is_boundary(e)))
+					{
+						float depth;
+
+						if (use_vert) {
+							for (uint j = 0; j < 2; j++) {
+								BMVert *v = *((&e->v1) + j);
+								float point[3];
+								mul_v3_m4v3(point, obedit->obmat, coords ? coords[BM_elem_index_get(v)] : v->co);
+								const float dist_sq_test = dist_squared_to_ray_v3(
+								        ray_origin, ray_direction,
+								        point, &depth);
+								if (dist_sq_test < dist_sq_best) {
+									dist_sq_best = dist_sq_test;
+									best.base = base_iter;
+									best.ele = (BMElem *)v;
+								}
+							}
+						}
+
+						if (use_edge) {
+							float point[3];
+#if 0
+							const float dist_sq_test = dist_squared_ray_to_seg_v3(
+							        ray_origin, ray_direction,
+							        e->v1->co,  e->v2->co,
+							        point, &depth);
+#else
+							if (coords) {
+								mid_v3_v3v3(point, coords[BM_elem_index_get(e->v1)], coords[BM_elem_index_get(e->v2)]);
+							}
+							else {
+								mid_v3_v3v3(point, e->v1->co, e->v2->co);
+							}
+							mul_m4_v3(obedit->obmat, point);
+							const float dist_sq_test = dist_squared_to_ray_v3(
+							        ray_origin, ray_direction,
+							        point, &depth);
+							if (dist_sq_test < dist_sq_best) {
+								dist_sq_best = dist_sq_test;
+								best.base = base_iter;
+								best.ele = (BMElem *)e;
+							}
+#endif
+						}
+					}
+				}
+			}
+			else {
+				/* Non boundary case. */
+				if (use_vert) {
+					BMVert *v;
+					BMIter viter;
+					BM_ITER_MESH (v, &viter, bm, BM_VERTS_OF_MESH) {
+						if (BM_elem_flag_test(v, BM_ELEM_HIDDEN) == false) {
+							float point[3];
+							mul_v3_m4v3(point, obedit->obmat, v->co);
+							float depth;
+							const float dist_sq_test = dist_squared_to_ray_v3(
+							        ray_origin, ray_direction,
+							        v->co, &depth);
+							if (dist_sq_test < dist_sq_best) {
+								dist_sq_best = dist_sq_test;
+								best.base = base_iter;
+								best.ele = (BMElem *)v;
+							}
+						}
+					}
+				}
+				if (use_edge) {
+					BMEdge *e;
+					BMIter eiter;
+					BM_ITER_MESH (e, &eiter, bm, BM_EDGES_OF_MESH) {
+						if (BM_elem_flag_test(e, BM_ELEM_HIDDEN) == false) {
+							float point[3];
+							if (coords) {
+								mid_v3_v3v3(point, coords[BM_elem_index_get(e->v1)], coords[BM_elem_index_get(e->v2)]);
+							}
+							else {
+								mid_v3_v3v3(point, e->v1->co, e->v2->co);
+							}
+							mul_m4_v3(obedit->obmat, point);
+							float depth;
+							const float dist_sq_test = dist_squared_to_ray_v3(
+							        ray_origin, ray_direction,
+							        point, &depth);
+							if (dist_sq_test < dist_sq_best) {
+								dist_sq_best = dist_sq_test;
+								best.base = base_iter;
+								best.ele = (BMElem *)e;
+							}
+						}
+					}
+				}
+			}
+
+			if (use_face) {
+				BMFace *f;
+				BMIter fiter;
+				BM_ITER_MESH (f, &fiter, bm, BM_FACES_OF_MESH) {
+					if (BM_elem_flag_test(f, BM_ELEM_HIDDEN) == false) {
+						float point[3];
+						if (coords) {
+							BM_face_calc_center_mean_vcos(bm, f, point, coords);
+						}
+						else {
+							BM_face_calc_center_mean(f, point);
+						}
+						mul_m4_v3(obedit->obmat, point);
+						float depth;
+						const float dist_sq_test = dist_squared_to_ray_v3(
+						        ray_origin, ray_direction,
+						        point, &depth);
+						if (dist_sq_test < dist_sq_best) {
+							dist_sq_best = dist_sq_test;
+							best.base = base_iter;
+							best.ele = (BMElem *)f;
+						}
+					}
+				}
+			}
+		}
+	}
+
+	*r_base = best.base;
+	if (r_eve) {
+		*r_eve = NULL;
+	}
+	if (r_eed) {
+		*r_eed = NULL;
+	}
+	if (r_efa) {
+		*r_efa = NULL;
+	}
+
+	if (best.ele) {
+		switch (best.ele->head.htype) {
+			case BM_VERT:
+				*r_eve = (BMVert *)best.ele;
+				break;
+			case BM_EDGE:
+				*r_eed = (BMEdge *)best.ele;
+				break;
+			case BM_FACE:
+				*r_efa = (BMFace *)best.ele;
+				break;
+			default:
+				BLI_assert(0);
+		}
+	}
+	return (best.ele != NULL);
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
 /** \name Select Similar (Vert/Edge/Face) Operator
  * \{ */
 
diff --git a/source/blender/editors/mesh/mesh_ops.c b/source/blender/editors/mesh/mesh_ops.c
index acd8079e75a..d1a3aec9551 100644
--- a/source/blender/editors/mesh/mesh_ops.c
+++ b/source/blender/editors/mesh/mesh_ops.c
@@ -157,7 +157,6 @@ void ED_operatortypes_mesh(void)
 	WM_operatortype_append(MESH_OT_polybuild_face_at_cursor);
 	WM_operatortype_append(MESH_OT_polybuild_split_at_cursor);
 	WM_operatortype_append(MESH_OT_polybuild_dissolve_at_cursor);
-	WM_operatortype_append(MESH_OT_polybuild_hover);
 
 	WM_operatortype_append(MESH_OT_uv_texture_add);
 	WM_operatortype_append(MESH_OT_uv_texture_remove);