From a61c1c4ab3ff0b432ca327d78cb2e2682dbc4d47 Mon Sep 17 00:00:00 2001
From: greisane <ggreisane@gmail.com>
Date: Tue, 19 Dec 2023 09:25:51 -0300
Subject: [PATCH] Bring back Graft face map output

---
 mesh/attribute_selection.py |  4 ++--
 mesh/graft.py               | 26 ++++++++++++++------------
 mesh/helpers.py             |  9 +++++++++
 3 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/mesh/attribute_selection.py b/mesh/attribute_selection.py
index e3e359e..feef52d 100644
--- a/mesh/attribute_selection.py
+++ b/mesh/attribute_selection.py
@@ -11,7 +11,7 @@ class GRET_OT_attribute_to_selection(bpy.types.Operator):
     """Set the current face selection from a boolean face attribute"""
 
     bl_idname = 'gret.attribute_to_selection'
-    bl_label = "Select Faces By Values"
+    bl_label = "Select Faces by Values"
     bl_options = {'REGISTER', 'UNDO'}
 
     @classmethod
@@ -50,7 +50,7 @@ class GRET_OT_attribute_from_selection(bpy.types.Operator):
     """Update or create a boolean face attribute from the current edit mode face selection"""
 
     bl_idname = 'gret.attribute_from_selection'
-    bl_label = "Face Selection To Values"
+    bl_label = "Face Selection to Values"
     bl_context = 'mesh_edit'
     bl_options = {'REGISTER', 'UNDO'}
 
diff --git a/mesh/graft.py b/mesh/graft.py
index 5b640d0..0edcbbf 100644
--- a/mesh/graft.py
+++ b/mesh/graft.py
@@ -2,9 +2,10 @@
 from math import pi
 import bmesh
 import bpy
+import numpy as np
 
 from ..math import get_dist_sq
-from .helpers import edit_mesh_elements, bmesh_vertex_group_bleed
+from .helpers import edit_mesh_elements, bmesh_vertex_group_bleed, get_face_map_attribute
 from ..helpers import with_object, get_modifier, get_vgroup, select_only, instant_modifier
 from ..operator import SaveContext
 
@@ -95,20 +96,13 @@ def do_graft(context, save, obj, dst_obj, expand=0, cuts=0, blend_distance=0.0,
     try:
         ret = bmesh.ops.bridge_loops(bm, edges=edges1+edges2, use_pairs=False,
             use_cyclic=False, use_merge=False, merge_factor=0.5, twist_offset=0)
-        new_faces = ret['faces']
+        new_face_indices = [face.index for face in ret['faces']]
         # for face in new_faces:
         #     face.smooth = True
     except RuntimeError:
         bm.free()
         raise GraftError("Couldn't bridge loops.")
 
-    # If requested, fill a face map with the new faces
-    # Disabled for 4.0 since there is no actual replacement for face-based selection haha
-    # if face_map_name:
-    #     face_map = obj.face_maps.get(face_map_name) or obj.face_maps.new(name=face_map_name)
-    #     for face in new_faces:
-    #         face[fm_layer] = face_map.index
-
     if cuts > 0:
         bmesh.ops.subdivide_edges(bm, edges=ret['edges'], smooth=1.0, smooth_falloff='LINEAR', cuts=cuts)
 
@@ -125,6 +119,14 @@ def do_graft(context, save, obj, dst_obj, expand=0, cuts=0, blend_distance=0.0,
     bm.to_mesh(obj.data)
     bm.free()
 
+    # If requested, fill a face map with the new faces
+    if face_map_name:
+        attr = get_face_map_attribute(obj, face_map_name)
+        values = np.empty(len(attr.data), dtype=bool)
+        attr.data.foreach_get('value', values)
+        values[new_face_indices] = True
+        attr.data.foreach_set('value', values)
+
     # Transfer stuff
     if copy_normals:
         obj.data.use_auto_smooth = True
@@ -195,8 +197,8 @@ class GRET_OT_graft(bpy.types.Operator):
     )
     face_map_name: bpy.props.StringProperty(
         name="Face Map Name",
-        description="Optional name of a face map that contains the new geometry",
-        default="Grafts",
+        description="Optional name of a boolean face attribute that contains the new geometry",
+        default="",
     )
     vertex_group_name: bpy.props.StringProperty(
         name="Vertex Group Name",
@@ -312,7 +314,7 @@ def draw(self, context):
 
         # layout.prop_search(self, 'vertex_group_name', obj, 'vertex_groups')
         layout.prop(self, 'vertex_group_name', icon='GROUP_VERTEX')
-        # layout.prop(self, 'face_map_name', icon='FACE_MAPS')
+        layout.prop(self, 'face_map_name', icon='FACE_MAPS')
 
         row = layout.row(align=True, heading="Copy")
         row.prop(self, 'copy_normals', text="Norms.", toggle=1)
diff --git a/mesh/helpers.py b/mesh/helpers.py
index bd0fea5..3728cb3 100644
--- a/mesh/helpers.py
+++ b/mesh/helpers.py
@@ -117,6 +117,15 @@ def refresh_active_color_attribute(mesh):
     if mesh.color_attributes.render_color_index < 0:
         mesh.color_attributes.render_color_index = 0
 
+def get_face_map_attribute(obj, name):
+    """Ensures that a boolean face attribute with the given name exists."""
+
+    assert obj.type == 'MESH'
+    attr = obj.data.attributes.get(name)
+    if not attr or attr.domain != 'FACE' or attr.data_type != 'BOOLEAN':
+        attr = obj.data.attributes.new(name, type='BOOLEAN', domain='FACE')
+    return attr
+
 def clear_object_data(obj, vertex_groups=True, shape_keys=True, face_maps=True, constraints=True,
     custom_properties=True, uv_layers=True, vertex_colors=True, attributes=True, materials=True):
     # Clear object data