Tool System: loopcut preview & activate on click

The loop cut tool now works as expected for the tool-system,
where hovering previews the loop and clicking activates.

This uses a new gizmo type to pre-select the edge.

release/scripts/startup/bl_ui/space_toolsystem_toolbar.py

@@ -679,7 +679,7 @@ class _defs_edit_mesh:
         return dict(
             text="Loop Cut",
             icon="ops.mesh.loopcut_slide",
-            widget=None,
+            widget="VIEW3D_GGT_mesh_preselect_edgering",
             keymap=(
                 ("mesh.loopcut_slide", dict(), dict(type='ACTIONMOUSE', value='PRESS')),
             ),

source/blender/editors/include/ED_gizmo_library.h

@@ -39,6 +39,7 @@ void ED_gizmotypes_cage_3d(void);
 void ED_gizmotypes_dial_3d(void);
 void ED_gizmotypes_grab_3d(void);
 void ED_gizmotypes_facemap_3d(void);
+void ED_gizmotypes_preselect_3d(void);
 void ED_gizmotypes_primitive_3d(void);
 void ED_gizmotypes_blank_3d(void);
 

source/blender/editors/mesh/editmesh_loopcut.c

@@ -436,6 +436,25 @@ static int loopcut_init(bContext *C, wmOperator *op, const wmEvent *event)
 
 static int ringcut_invoke(bContext *C, wmOperator *op, const wmEvent *event)
 {
+	/* When accessed as a tool, get the active edge from the preselection gizmo. */
+	{
+		ARegion *ar = CTX_wm_region(C);
+		wmGizmoMap *gzmap = ar->gizmo_map;
+		wmGizmoGroup *gzgroup = gzmap ? WM_gizmomap_group_find(gzmap, "VIEW3D_GGT_mesh_preselect_edgering") : NULL;
+		if (gzgroup != NULL) {
+			wmGizmo *gz = gzgroup->gizmos.first;
+			const int object_index = RNA_int_get(gz->ptr, "object_index");
+			const int edge_index = RNA_int_get(gz->ptr, "edge_index");
+
+			if (object_index != -1 && edge_index != -1) {
+				RNA_int_set(op->ptr, "object_index", object_index);
+				RNA_int_set(op->ptr, "edge_index", edge_index);
+				return loopcut_init(C, op, NULL);
+			}
+			return OPERATOR_CANCELLED;
+		}
+	}
+
 	return loopcut_init(C, op, event);
 }
 

source/blender/editors/space_api/spacetypes.c

@@ -135,6 +135,7 @@ void ED_spacetypes_init(void)
 	ED_gizmotypes_grab_3d();
 	ED_gizmotypes_arrow_2d();
 	ED_gizmotypes_arrow_3d();
+	ED_gizmotypes_preselect_3d();
 	ED_gizmotypes_primitive_3d();
 	ED_gizmotypes_blank_3d();
 	ED_gizmotypes_cage_2d();

source/blender/editors/space_view3d/CMakeLists.txt

@@ -63,6 +63,8 @@ set(SRC
 	view3d_gizmo_navigate.c
 	view3d_gizmo_navigate_type.c
 	view3d_gizmo_ruler.c
+	view3d_gizmo_preselect.c
+	view3d_gizmo_preselect_type.c
 	view3d_ops.c
 	view3d_project.c
 	view3d_ruler.c

source/blender/editors/space_view3d/space_view3d.c

@@ -705,6 +705,7 @@ static void view3d_widgets(void)
 
 	WM_gizmogrouptype_append(TRANSFORM_GGT_gizmo);
 	WM_gizmogrouptype_append(VIEW3D_GGT_xform_cage);
+	WM_gizmogrouptype_append(VIEW3D_GGT_mesh_preselect_edgering);
 
 	WM_gizmogrouptype_append(VIEW3D_GGT_ruler);
 	WM_gizmotype_append(VIEW3D_GT_ruler_item);

source/blender/editors/space_view3d/view3d_gizmo_preselect.c

@@ -0,0 +1,89 @@
+/*
+ * ***** 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/space_view3d/view3d_gizmo_preselect.c
+ *  \ingroup spview3d
+ */
+
+#include "MEM_guardedalloc.h"
+
+#include "BLI_blenlib.h"
+#include "BLI_math.h"
+#include "BLI_utildefines.h"
+
+#include "BKE_context.h"
+
+#include "ED_screen.h"
+
+#include "UI_resources.h"
+
+#include "WM_api.h"
+#include "WM_types.h"
+#include "WM_toolsystem.h"
+
+#include "view3d_intern.h"  /* own include */
+
+/* -------------------------------------------------------------------- */
+/** \name Mesh Pre-Select Edge Ring Gizmo
+ *
+ * \{ */
+
+struct GizmoGroupPreSelEdgeRing {
+	wmGizmo *gizmo;
+};
+
+static bool WIDGETGROUP_mesh_preselect_edgering_poll(const bContext *C, wmGizmoGroupType *gzgt)
+{
+	bToolRef_Runtime *tref_rt = WM_toolsystem_runtime_from_context((bContext *)C);
+	if ((tref_rt == NULL) ||
+	    !STREQ(gzgt->idname, tref_rt->gizmo_group))
+	{
+		WM_gizmo_group_type_unlink_delayed_ptr(gzgt);
+		return false;
+	}
+	return true;
+}
+
+static void WIDGETGROUP_mesh_preselect_edgering_setup(const bContext *UNUSED(C), wmGizmoGroup *gzgroup)
+{
+	const wmGizmoType *gzt_presel = WM_gizmotype_find("GIZMO_GT_preselect_edgering_3d", true);
+	struct GizmoGroupPreSelEdgeRing *man = MEM_callocN(sizeof(struct GizmoGroupPreSelEdgeRing), __func__);
+	gzgroup->customdata = man;
+
+	wmGizmo *gz = man->gizmo = WM_gizmo_new_ptr(gzt_presel, gzgroup, NULL);
+	UI_GetThemeColor3fv(TH_GIZMO_PRIMARY, gz->color);
+	UI_GetThemeColor3fv(TH_GIZMO_HI, gz->color_hi);
+}
+
+void VIEW3D_GGT_mesh_preselect_edgering(wmGizmoGroupType *gzgt)
+{
+	gzgt->name = "Mesh Preselect Edge Ring";
+	gzgt->idname = "VIEW3D_GGT_mesh_preselect_edgering";
+
+	gzgt->flag = WM_GIZMOGROUPTYPE_3D;
+
+	gzgt->gzmap_params.spaceid = SPACE_VIEW3D;
+	gzgt->gzmap_params.regionid = RGN_TYPE_WINDOW;
+
+	gzgt->poll = WIDGETGROUP_mesh_preselect_edgering_poll;
+	gzgt->setup = WIDGETGROUP_mesh_preselect_edgering_setup;
+}
+
+/** \} */

source/blender/editors/space_view3d/view3d_gizmo_preselect_type.c

@@ -0,0 +1,203 @@
+/*
+ * ***** 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 view3d_gizmo_preselect_type.c
+ *  \ingroup wm
+ *
+ * \name Preselection Gizmo
+ *
+ * Use for tools to hover over data before activation.
+ *
+ * \note This is a slight mis-use of gizmo's, since clicking performs no action.
+ */
+
+#include "MEM_guardedalloc.h"
+
+#include "BLI_math.h"
+
+#include "BKE_context.h"
+#include "BKE_layer.h"
+#include "BKE_editmesh.h"
+
+#include "RNA_access.h"
+#include "RNA_define.h"
+
+#include "WM_api.h"
+#include "WM_types.h"
+
+#include "bmesh.h"
+
+#include "ED_screen.h"
+#include "ED_mesh.h"
+#include "ED_view3d.h"
+#include "ED_gizmo_library.h"
+
+/* -------------------------------------------------------------------- */
+/** \name Mesh Edge-Ring Pre-Select Gizmo API
+ *
+ * \{ */
+
+typedef struct MeshEdgeRingGizmo3D {
+	wmGizmo gizmo;
+	Object **objects;
+	uint     objects_len;
+	int object_index;
+	int edge_index;
+	struct EditMesh_PreSelEdgeRing *psel;
+} MeshEdgeRingGizmo3D;
+
+static void gizmo_preselect_edgering_draw(const bContext *UNUSED(C), wmGizmo *gz)
+{
+	MeshEdgeRingGizmo3D *gz_ring = (MeshEdgeRingGizmo3D *)gz;
+	if (gz_ring->object_index != -1) {
+		Object *ob = gz_ring->objects[gz_ring->object_index];
+		EDBM_preselect_edgering_draw(gz_ring->psel, ob->obmat);
+	}
+}
+
+static int gizmo_preselect_edgering_test_select(
+        bContext *C, wmGizmo *gz, const int mval[2])
+{
+	MeshEdgeRingGizmo3D *gz_ring = (MeshEdgeRingGizmo3D *)gz;
+	struct {
+		Object *ob;
+		BMEdge *eed;
+		float dist;
+		int ob_index;
+	} best = {
+		.dist = ED_view3d_select_dist_px(),
+	};
+
+	struct {
+		int object_index;
+		int edge_index;
+	} prev = {
+		.object_index = gz_ring->object_index,
+		.edge_index = gz_ring->edge_index,
+	};
+
+	if (gz_ring->objects == NULL) {
+		ViewLayer *view_layer = CTX_data_view_layer(C);
+		gz_ring->objects = BKE_view_layer_array_from_objects_in_edit_mode(
+		        view_layer, &gz_ring->objects_len);
+	}
+
+	ViewContext vc;
+	em_setup_viewcontext(C, &vc);
+	copy_v2_v2_int(vc.mval, mval);
+
+	for (uint ob_index = 0; ob_index < gz_ring->objects_len; ob_index++) {
+		Object *ob_iter = gz_ring->objects[ob_index];
+		ED_view3d_viewcontext_init_object(&vc, ob_iter);
+		BMEdge *eed_test = EDBM_edge_find_nearest_ex(&vc, &best.dist, NULL, false, false, NULL);
+		if (eed_test) {
+			best.ob = ob_iter;
+			best.eed = eed_test;
+			best.ob_index = ob_index;
+		}
+	}
+
+	BMesh *bm = NULL;
+	if (best.eed) {
+		gz_ring->object_index = best.ob_index;
+		bm = BKE_editmesh_from_object(gz_ring->objects[gz_ring->object_index])->bm;
+		BM_mesh_elem_index_ensure(bm, BM_EDGE);
+		gz_ring->edge_index = BM_elem_index_get(best.eed);
+	}
+	else {
+		gz_ring->object_index = -1;
+		gz_ring->edge_index = -1;
+	}
+
+
+	if ((prev.object_index == gz_ring->object_index) &&
+	    (prev.edge_index == gz_ring->edge_index))
+	{
+		/* pass (only recalculate on change) */
+	}
+	else {
+		if (best.eed) {
+			EDBM_preselect_edgering_update_from_edge(
+			        gz_ring->psel,
+			        bm, best.eed, 1);
+		}
+		else {
+			EDBM_preselect_edgering_clear(gz_ring->psel);
+		}
+
+		RNA_int_set(gz->ptr, "object_index", gz_ring->object_index);
+		RNA_int_set(gz->ptr, "edge_index", gz_ring->edge_index);
+
+		ARegion *ar = CTX_wm_region(C);
+		ED_region_tag_redraw(ar);
+	}
+
+	// return best.eed ? 0 : -1;
+	return -1;
+}
+
+static void gizmo_preselect_edgering_setup(wmGizmo *gz)
+{
+	MeshEdgeRingGizmo3D *gz_ring = (MeshEdgeRingGizmo3D *)gz;
+	if (gz_ring->psel == NULL) {
+		gz_ring->psel = EDBM_preselect_edgering_create();
+	}
+	gz_ring->object_index = -1;
+}
+
+static void gizmo_preselect_edgering_free(wmGizmo *gz)
+{
+	MeshEdgeRingGizmo3D *gz_ring = (MeshEdgeRingGizmo3D *)gz;
+	EDBM_preselect_edgering_destroy(gz_ring->psel);
+	gz_ring->psel = NULL;
+	MEM_SAFE_FREE(gz_ring->objects);
+}
+
+static int gizmo_preselect_edgering_invoke(
+        bContext *UNUSED(C), wmGizmo *UNUSED(gz), const wmEvent *UNUSED(event))
+{
+	return OPERATOR_PASS_THROUGH;
+}
+
+
+static void GIZMO_GT_preselect_edgering_3d(wmGizmoType *gzt)
+{
+	/* identifiers */
+	gzt->idname = "GIZMO_GT_preselect_edgering_3d";
+
+	/* api callbacks */
+	gzt->invoke = gizmo_preselect_edgering_invoke;
+	gzt->draw = gizmo_preselect_edgering_draw;
+	gzt->test_select = gizmo_preselect_edgering_test_select;
+	gzt->setup = gizmo_preselect_edgering_setup;
+	gzt->free = gizmo_preselect_edgering_free;
+
+	gzt->struct_size = sizeof(MeshEdgeRingGizmo3D);
+
+	RNA_def_int(gzt->srna, "object_index", -1, -1, INT_MAX, "Object Index", "", -1, INT_MAX);
+	RNA_def_int(gzt->srna, "edge_index", -1, -1, INT_MAX, "Edge Index", "", -1, INT_MAX);
+}
+
+void ED_gizmotypes_preselect_3d(void)
+{
+	WM_gizmotype_append(GIZMO_GT_preselect_edgering_3d);
+}
+
+/** \} */

source/blender/editors/space_view3d/view3d_intern.h

@@ -263,6 +263,7 @@ void VIEW3D_GGT_force_field(struct wmGizmoGroupType *gzgt);
 void VIEW3D_GGT_empty_image(struct wmGizmoGroupType *gzgt);
 void VIEW3D_GGT_armature_spline(struct wmGizmoGroupType *gzgt);
 void VIEW3D_GGT_navigate(struct wmGizmoGroupType *gzgt);
+void VIEW3D_GGT_mesh_preselect_edgering(struct wmGizmoGroupType *gzgt);
 
 void VIEW3D_GGT_ruler(struct wmGizmoGroupType *gzgt);
 void VIEW3D_GT_ruler_item(struct wmGizmoType *gzt);