Rigify: add support for user-defined rig packages and related utilities.

As suggested by @icappielo, and after discussion with @meta-androcto,
I start a public request to commit third-party contributions already
accepted to https://github.com/eigen-value/rigify/tree/rigify_0.6_beta

Specifically, this includes:

* User-defined rig package (feature set) support by @pioverfour.
  This allows users to install pre-packaged rig sets via zip
  files, which become accessible together with built-in rigs,
  as discussed in T52758.

  https://github.com/eigen-value/rigify/pull/1

* Modularization of python script generation, allowing rigs to
  add their own utility functions and operators to the generated
  script. This is critical to make custom rig support really
  useful.

  https://github.com/eigen-value/rigify/pull/5

* The utils.py file is split into multiple modules with a backward
  compatibility proxy for old functions.

* Automatic verification that different rigs don't try to create
  different rig settings with the same name to alleviate increased
  risk of namespace conflicts with custom rigs.

  https://github.com/eigen-value/rigify/pull/7

* New utility class that implements bone layer selection UI.

  https://github.com/eigen-value/rigify/pull/6

* New utilities to replace copy & pasted boilerplate code for
  creating custom properties, constraints and drivers.

  https://github.com/eigen-value/rigify/pull/11

Some other random changes by MAD have likely slipped through.

These changes have already been extensively discussed and accepted
into the branch by @luciorossi, so I see no reason not to commit
them to the official repository to be tested during 2.8 beta.

Reviewers: icappiello

Differential Revision: https://developer.blender.org/D4364

1 files changed, 168 insertions, 0 deletions

diff --git a/rigify/utils/widgets.py b/rigify/utils/widgets.py
new file mode 100644
index 00000000..184429a3
--- /dev/null
+++ b/rigify/utils/widgets.py
@@ -0,0 +1,168 @@
+#====================== 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 ========================
+
+# <pep8 compliant>
+
+import bpy
+import math
+
+from .errors import MetarigError
+
+WGT_PREFIX = "WGT-"  # Prefix for widget objects
+
+#=============================================
+# Widget creation
+#=============================================
+
+
+def obj_to_bone(obj, rig, bone_name):
+    """ Places an object at the location/rotation/scale of the given bone.
+    """
+    if bpy.context.mode == 'EDIT_ARMATURE':
+        raise MetarigError("obj_to_bone(): does not work while in edit mode")
+
+    bone = rig.data.bones[bone_name]
+
+    mat = rig.matrix_world @ bone.matrix_local
+
+    obj.location = mat.to_translation()
+
+    obj.rotation_mode = 'XYZ'
+    obj.rotation_euler = mat.to_euler()
+
+    scl = mat.to_scale()
+    scl_avg = (scl[0] + scl[1] + scl[2]) / 3
+    obj.scale = (bone.length * scl_avg), (bone.length * scl_avg), (bone.length * scl_avg)
+
+
+def create_widget(rig, bone_name, bone_transform_name=None):
+    """ Creates an empty widget object for a bone, and returns the object.
+    """
+    if bone_transform_name is None:
+        bone_transform_name = bone_name
+
+    obj_name = WGT_PREFIX + rig.name + '_' + bone_name
+    scene = bpy.context.scene
+    collection = bpy.context.collection
+
+    # Check if it already exists in the scene
+    if obj_name in scene.objects:
+        # Move object to bone position, in case it changed
+        obj = scene.objects[obj_name]
+        obj_to_bone(obj, rig, bone_transform_name)
+
+        return None
+    else:
+        # Delete object if it exists in blend data but not scene data.
+        # This is necessary so we can then create the object without
+        # name conflicts.
+        if obj_name in bpy.data.objects:
+            bpy.data.objects[obj_name].user_clear()
+            bpy.data.objects.remove(bpy.data.objects[obj_name])
+
+        # Create mesh object
+        mesh = bpy.data.meshes.new(obj_name)
+        obj = bpy.data.objects.new(obj_name, mesh)
+        collection.objects.link(obj)
+
+        # Move object to bone position and set layers
+        obj_to_bone(obj, rig, bone_transform_name)
+        wgts_group_name = 'WGTS_' + rig.name
+        if wgts_group_name in bpy.data.objects.keys():
+            obj.parent = bpy.data.objects[wgts_group_name]
+
+        return obj
+
+
+def create_circle_polygon(number_verts, axis, radius=1.0, head_tail=0.0):
+    """ Creates a basic circle around of an axis selected.
+        number_verts: number of vertices of the poligon
+        axis: axis normal to the circle
+        radius: the radius of the circle
+        head_tail: where along the length of the bone the circle is (0.0=head, 1.0=tail)
+    """
+    verts = []
+    edges = []
+    angle = 2 * math.pi / number_verts
+    i = 0
+
+    assert(axis in 'XYZ')
+
+    while i < (number_verts):
+        a = math.cos(i * angle)
+        b = math.sin(i * angle)
+
+        if axis == 'X':
+            verts.append((head_tail, a * radius, b * radius))
+        elif axis == 'Y':
+            verts.append((a * radius, head_tail, b * radius))
+        elif axis == 'Z':
+            verts.append((a * radius, b * radius, head_tail))
+
+        if i < (number_verts - 1):
+            edges.append((i , i + 1))
+
+        i += 1
+
+    edges.append((0, number_verts - 1))
+
+    return verts, edges
+
+
+def write_widget(obj):
+    """ Write a mesh object as a python script for widget use.
+    """
+    script = ""
+    script += "def create_thing_widget(rig, bone_name, size=1.0, bone_transform_name=None):\n"
+    script += "    obj = create_widget(rig, bone_name, bone_transform_name)\n"
+    script += "    if obj != None:\n"
+
+    # Vertices
+    if len(obj.data.vertices) > 0:
+        script += "        verts = ["
+        for v in obj.data.vertices:
+            script += "(" + str(v.co[0]) + "*size, " + str(v.co[1]) + "*size, " + str(v.co[2]) + "*size), "
+        script += "]\n"
+
+    # Edges
+    if len(obj.data.edges) > 0:
+        script += "        edges = ["
+        for e in obj.data.edges:
+            script += "(" + str(e.vertices[0]) + ", " + str(e.vertices[1]) + "), "
+        script += "]\n"
+
+    # Faces
+    if len(obj.data.polygons) > 0:
+        script += "        faces = ["
+        for f in obj.data.polygons:
+            script += "("
+            for v in f.vertices:
+                script += str(v) + ", "
+            script += "), "
+        script += "]\n"
+
+    # Build mesh
+    script += "\n        mesh = obj.data\n"
+    script += "        mesh.from_pydata(verts, edges, faces)\n"
+    script += "        mesh.update()\n"
+    script += "        mesh.update()\n"
+    script += "        return obj\n"
+    script += "    else:\n"
+    script += "        return None\n"
+
+    return script