scripts-blender/addons/asset_pipeline_2/merge/transfer_data/transfer_functions.py

@@ -478,20 +478,14 @@ def transfer_material_slots(target_obj: bpy.types.Object, source_obj):
 # SHAPE KEYS
 
 
-def shape_key_set_active(obj, shape_key_name):
+def closest_face_to_point(bm_source, p_target, bvh_tree=None):
-    for index, shape_key in enumerate(obj.data.shape_keys.key_blocks):
-        if shape_key.name == shape_key_name:
-            obj.active_shape_key_index = index
-
-
-def shape_key_closest_face_to_point(bm_source, p_target, bvh_tree=None):
     if not bvh_tree:
         bvh_tree = mathutils.bvhtree.BVHTree.FromBMesh(bm_source)
     (loc, norm, index, distance) = bvh_tree.find_nearest(p_target)
     return bm_source.faces[index]
 
 
-def shape_key_tris_per_face(bm_source):
+def tris_per_face(bm_source):
     tris_source = bm_source.calc_loop_triangles()
     tris_dict = dict()
     for face in bm_source.faces:
@@ -503,7 +497,7 @@ def shape_key_tris_per_face(bm_source):
     return tris_dict
 
 
-def shape_key_closest_tri_on_face(tris_dict, face, p):
+def closest_tri_on_face(tris_dict, face, p):
     points = []
     dist = []
     tris = []
@@ -520,6 +514,203 @@ def shape_key_closest_tri_on_face(tris_dict, face, p):
     return (tri, point)
 
 
+def closest_edge_on_face_to_line(face, p1, p2, skip_edges=None):
+    """Returns edge of a face which is closest to line."""
+    for edge in face.edges:
+        if skip_edges:
+            if edge in skip_edges:
+                continue
+        res = mathutils.geometry.intersect_line_line(
+            p1, p2, *[edge.verts[i].co for i in range(2)]
+        )
+        if not res:
+            continue
+        (p_traversal, p_edge) = res
+        frac_1 = (edge.verts[1].co - edge.verts[0].co).dot(
+            p_edge - edge.verts[0].co
+        ) / (edge.verts[1].co - edge.verts[0].co).length ** 2.0
+        frac_2 = (p2 - p1).dot(p_traversal - p1) / (p2 - p1).length ** 2.0
+        if (frac_1 >= 0 and frac_1 <= 1) and (frac_2 >= 0 and frac_2 <= 1):
+            return edge
+    return None
+
+
+def edge_data_split(edge, data_layer, data_suffix: str):
+    for vert in edge.verts:
+        vals = []
+        for loop in vert.link_loops:
+            loops_edge_vert = set([loop for f in edge.link_faces for loop in f.loops])
+            if loop not in loops_edge_vert:
+                continue
+            dat = data_layer[loop.index]
+            element = list(getattr(dat, data_suffix))
+            if not vals:
+                vals.append(element)
+            elif not vals[0] == element:
+                vals.append(element)
+        if len(vals) > 1:
+            return True
+    return False
+
+
+def interpolate_data_from_face(
+    bm_source, tris_dict, face, p, data_layer_source, data_suffix=''
+):
+    """Returns interpolated value of a data layer within a face closest to a point."""
+
+    (tri, point) = closest_tri_on_face(tris_dict, face, p)
+    if not tri:
+        return None
+    weights = mathutils.interpolate.poly_3d_calc(
+        [tri[i].vert.co for i in range(3)], point
+    )
+
+    if not data_suffix:
+        cols_weighted = [
+            weights[i] * np.array(data_layer_source[tri[i].index]) for i in range(3)
+        ]
+        col = sum(np.array(cols_weighted))
+    else:
+        cols_weighted = [
+            weights[i] * np.array(getattr(data_layer_source[tri[i].index], data_suffix))
+            for i in range(3)
+        ]
+        col = sum(np.array(cols_weighted))
+    return col
+
+
+def transfer_corner_data(
+    obj_source, obj_target, data_layer_source, data_layer_target, data_suffix=''
+):
+    """
+    Transfers interpolated face corner data from data layer of a source object to data layer of a
+    target object, while approximately preserving data seams (e.g. necessary for UV Maps).
+    The transfer is face interpolated per target corner within the source face that is closest
+    to the target corner point and does not have any data seams on the way back to the
+    source face that is closest to the target face's center.
+    """
+
+    bm_source = bmesh.new()
+    bm_source.from_mesh(obj_source.data)
+    bm_source.faces.ensure_lookup_table()
+    bm_target = bmesh.new()
+    bm_target.from_mesh(obj_target.data)
+    bm_target.faces.ensure_lookup_table()
+
+    bvh_tree = mathutils.bvhtree.BVHTree.FromBMesh(bm_source)
+
+    tris_dict = tris_per_face(bm_source)
+
+    for face_target in bm_target.faces:
+        face_target_center = face_target.calc_center_median()
+
+        face_source = closest_face_to_point(bm_source, face_target_center, bvh_tree)
+
+        for corner_target in face_target.loops:
+            # find nearest face on target compared to face that loop belongs to
+            p = corner_target.vert.co
+
+            face_source_closest = closest_face_to_point(bm_source, p, bvh_tree)
+            enclosed = face_source_closest is face_source
+            face_source_int = face_source
+            if not enclosed:
+                # traverse faces between point and face center
+                traversed_faces = set()
+                traversed_edges = set()
+                while face_source_int is not face_source_closest:
+                    traversed_faces.add(face_source_int)
+                    edge = closest_edge_on_face_to_line(
+                        face_source_int,
+                        face_target_center,
+                        p,
+                        skip_edges=traversed_edges,
+                    )
+                    if edge == None:
+                        break
+                    if len(edge.link_faces) != 2:
+                        break
+                    traversed_edges.add(edge)
+
+                    split = edge_data_split(edge, data_layer_source, data_suffix)
+                    if split:
+                        break
+
+                    # set new source face to other face belonging to edge
+                    face_source_int = (
+                        edge.link_faces[1]
+                        if edge.link_faces[1] is not face_source_int
+                        else edge.link_faces[0]
+                    )
+
+                    # avoid looping behaviour
+                    if face_source_int in traversed_faces:
+                        face_source_int = face_source
+                        break
+
+            # interpolate data from selected face
+            col = interpolate_data_from_face(
+                bm_source, tris_dict, face_source_int, p, data_layer_source, data_suffix
+            )
+            if col is None:
+                continue
+            if not data_suffix:
+                data_layer_target.data[corner_target.index] = col
+            else:
+                setattr(data_layer_target[corner_target.index], data_suffix, list(col))
+    return
+
+
+def is_mesh_identical(mesh_a, mesh_b) -> bool:
+    if len(mesh_a.vertices) != len(mesh_b.vertices):
+        return False
+    if len(mesh_a.edges) != len(mesh_b.edges):
+        return False
+    if len(mesh_a.polygons) != len(mesh_b.polygons):
+        return False
+    for e1, e2 in zip(mesh_a.edges, mesh_b.edges):
+        for v1, v2 in zip(e1.vertices, e2.vertices):
+            if v1 != v2:
+                return False
+
+    return True
+
+
+def is_curve_identical(curve_a: bpy.types.Curve, curve_b: bpy.types.Curve) -> bool:
+    if len(curve_a.splines) != len(curve_b.splines):
+        return False
+    for spline1, spline2 in zip(curve_a.splines, curve_b.splines):
+        if len(spline1.points) != len(spline2.points):
+            return False
+    return True
+
+
+def is_obdata_identical(
+    a: bpy.types.Object or bpy.types.Mesh, b: bpy.types.Object or bpy.types.Mesh
+) -> bool:
+    """Checks if two objects have matching topology (efficiency over exactness)"""
+    if type(a) == bpy.types.Object:
+        a = a.data
+    if type(b) == bpy.types.Object:
+        b = b.data
+
+    if type(a) != type(b):
+        return False
+
+    if type(a) == bpy.types.Mesh:
+        return is_mesh_identical(a, b)
+    elif type(a) == bpy.types.Curve:
+        return is_curve_identical(a, b)
+    else:
+        # TODO: Support geometry types other than mesh or curve.
+        return
+
+
+def shape_key_set_active(obj, shape_key_name):
+    for index, shape_key in enumerate(obj.data.shape_keys.key_blocks):
+        if shape_key.name == shape_key_name:
+            obj.active_shape_key_index = index
+
+
 def shape_keys_clean(obj):
     if obj.type != "MESH" or obj.data.shape_keys is None:
         return
@@ -618,12 +809,12 @@ def transfer_shape_key(
     bm_source.faces.ensure_lookup_table()
 
     bvh_tree = mathutils.bvhtree.BVHTree.FromBMesh(bm_source)
-    tris_dict = shape_key_tris_per_face(bm_source)
+    tris_dict = tris_per_face(bm_source)
     for i, vert in enumerate(target_obj.data.vertices):
         p = vert.co
-        face = shape_key_closest_face_to_point(bm_source, p, bvh_tree)
+        face = closest_face_to_point(bm_source, p, bvh_tree)
 
-        (tri, point) = shape_key_closest_tri_on_face(tris_dict, face, p)
+        (tri, point) = closest_tri_on_face(tris_dict, face, p)
         if not tri:
             continue
         weights = mathutils.interpolate.poly_3d_calc(
@@ -730,8 +921,8 @@ def transfer_attribute(
     source_attributes = source_obj.data.attributes
     target_attributes = target_obj.data.attributes
     source_attribute = source_attributes.get(attribute_name)
-
     target_attribute = target_attributes.get(attribute_name)
+
     if target_attribute:
         target_attributes.remove(target_attribute)
 
@@ -740,7 +931,13 @@ def transfer_attribute(
         type=source_attribute.data_type,
         domain=source_attribute.domain,
     )
-    # print(f"Transfering Attribute {attribute_name}")
+
+    if not is_obdata_identical(source_obj, target_obj):
+        proximity_transfer_single_attribute(
+            source_obj, target_obj, source_attribute, target_attribute
+        )
+        return
+
     for source_data_item in source_attribute.data.items():
         index = source_data_item[0]
         source_data = source_data_item[1]
@@ -752,6 +949,134 @@ def transfer_attribute(
             setattr(target_data, key, getattr(source_data, key))
 
 
+def proximity_transfer_single_attribute(
+    source_obj: bpy.types.Object,
+    target_obj: bpy.types.Object,
+    source_attribute: bpy.types.Attribute,
+    target_attribute: bpy.types.Attribute,
+):
+    # src_dat = source_obj.data
+    # tgt_dat = target_obj.data
+    # if type(src_dat) is not type(tgt_dat) or not (src_dat or tgt_dat):
+    #     return False
+    # if type(tgt_dat) is not bpy.types.Mesh:  # TODO: support more types
+    #     return False
+
+    # If target attribute already exists, remove it.
+    # tgt_attr = tgt_dat.attributes.get(source_attribute.name)
+    # if tgt_attr is not None:
+    #     try:
+    #         tgt_dat.attributes.remove(tgt_attr)
+    #     except RuntimeError:
+    #         # Built-ins like "position" cannot be removed, and should be skipped.
+    #         return
+
+    # Create target attribute.
+    # target_attribute = tgt_dat.attributes.new(
+    #     source_attribute.name, source_attribute.data_type, source_attribute.domain
+    # )
+
+    data_sfx = {
+        'INT8': 'value',
+        'INT': 'value',
+        'FLOAT': 'value',
+        'FLOAT2': 'vector',
+        'BOOLEAN': 'value',
+        'STRING': 'value',
+        'BYTE_COLOR': 'color',
+        'FLOAT_COLOR': 'color',
+        'FLOAT_VECTOR': 'vector',
+    }
+
+    data_sfx = data_sfx[source_attribute.data_type]
+
+    # if topo_match:
+    #     # TODO: optimize using foreach_get/set rather than loop
+    #     for i in range(len(source_attribute.data)):
+    #         setattr(tgt_attr.data[i], data_sfx, getattr(source_attribute.data[i], data_sfx))
+    #     return
+
+    # proximity fallback
+    if source_attribute.data_type == 'STRING':
+        # TODO: add NEAREST transfer fallback for attributes without interpolation
+        print(
+            f'Proximity based transfer for generic attributes of type STRING not supported yet. Skipping attribute {source_attribute.name} on {target_obj}.'
+        )
+        return
+
+    domain = source_attribute.domain
+    if (
+        domain == 'POINT'
+    ):  # TODO: deduplicate interpolated point domain proximity transfer
+        bm_source = bmesh.new()
+        bm_source.from_mesh(source_obj.data)
+        bm_source.faces.ensure_lookup_table()
+
+        bvh_tree = mathutils.bvhtree.BVHTree.FromBMesh(bm_source)
+
+        tris_dict = tris_per_face(bm_source)
+
+        for i, vert in enumerate(target_obj.data.vertices):
+            p = vert.co
+            face = closest_face_to_point(bm_source, p, bvh_tree)
+
+            (tri, point) = closest_tri_on_face(tris_dict, face, p)
+            if not tri:
+                continue
+            weights = mathutils.interpolate.poly_3d_calc(
+                [tri[i].vert.co for i in range(3)], point
+            )
+
+            if data_sfx in ['color']:
+                vals_weighted = [
+                    weights[i]
+                    * (
+                        np.array(
+                            getattr(source_attribute.data[tri[i].vert.index], data_sfx)
+                        )
+                    )
+                    for i in range(3)
+                ]
+            else:
+                vals_weighted = [
+                    weights[i]
+                    * (getattr(source_attribute.data[tri[i].vert.index], data_sfx))
+                    for i in range(3)
+                ]
+            setattr(target_attribute.data[i], data_sfx, sum(np.array(vals_weighted)))
+        return
+    elif domain == 'EDGE':
+        # TODO support proximity fallback for generic edge attributes
+        print(
+            f'Proximity based transfer of generic edge attributes not supported yet. Skipping attribute {source_attribute.name} on {target_obj}.'
+        )
+        return
+    elif domain == 'FACE':
+        bm_source = bmesh.new()
+        bm_source.from_mesh(source_obj.data)
+        bm_source.faces.ensure_lookup_table()
+
+        bvh_tree = mathutils.bvhtree.BVHTree.FromBMesh(bm_source)
+        for i, face in enumerate(target_obj.data.polygons):
+            p_target = face.center
+            closest_face = closest_face_to_point(bm_source, p_target, bvh_tree)
+            setattr(
+                target_attribute.data[i],
+                data_sfx,
+                getattr(source_attribute.data[closest_face.index], data_sfx),
+            )
+        return
+    elif domain == 'CORNER':
+        transfer_corner_data(
+            source_obj,
+            target_obj,
+            source_attribute.data,
+            target_attribute.data,
+            data_suffix=data_sfx,
+        )
+        return
+
+
 def parent_clean(obj):
     matches = check_transfer_data_entry(
         obj.transfer_data_ownership,