- WIP add nla alignment UI in python

4 files changed, 126 insertions, 8 deletions

diff --git a/release/scripts/startup/bl_ui/__init__.py b/release/scripts/startup/bl_ui/__init__.py
index 7d3ecceca41..e782ff7bfe3 100644
--- a/release/scripts/startup/bl_ui/__init__.py
+++ b/release/scripts/startup/bl_ui/__init__.py
@@ -49,6 +49,7 @@ _modules = [
     "properties_mask_common",
     "properties_material",
     "properties_material_gpencil",
+    "properties_nla",
     "properties_object",
     "properties_paint_common",
     "properties_grease_pencil_common",
diff --git a/release/scripts/startup/bl_ui/properties_nla.py b/release/scripts/startup/bl_ui/properties_nla.py
new file mode 100644
index 00000000000..88040a5f671
--- /dev/null
+++ b/release/scripts/startup/bl_ui/properties_nla.py
@@ -0,0 +1,113 @@
+# ##### 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>
+from bpy.types import Panel
+from bpy.props import (StringProperty,
+                       BoolProperty,
+                       IntProperty,
+                       FloatProperty,
+                       EnumProperty,
+                       PointerProperty,
+                       CollectionProperty,
+                       FloatVectorProperty,
+                       IntVectorProperty,
+                       )
+def get_active_strip(context):
+    return next([strip for strip in context.selected_nla_strips if strip.active],None)
+
+class OBJECT_OT_nla_preblend_add_bone(bpy.types.Operator):
+    bl_idname = "pose.null_op"
+    bl_label = "NULL OP"
+    bl_options = {'REGISTER', 'UNDO'}
+
+    preblend_index : IntProperty()
+
+    @classmethod
+    def poll(cls,context):
+        return context.selected_nla_strips
+
+    def execute(self, context):
+        active_strip = get_active_strip()
+        preblend = active_strip.preblend_transforms[self.preblend_index]
+        preblend.bones.add()
+
+        return {'FINISHED'}
+class OBJECT_OT_nla_preblend_remove_bone(bpy.types.Operator):
+    bl_idname = "pose.null_op"
+    bl_label = "NULL OP"
+    bl_options = {'REGISTER', 'UNDO'}
+
+    preblend_index : IntProperty()
+    bone_index : IntProperty()
+
+    @classmethod
+    def poll(cls,context):
+        return context.selected_nla_strips
+
+    def execute(self, context):
+        active_strip = get_active_strip()
+        preblend = active_strip.preblend_transforms[self.preblend_index]
+        preblend.bones.remove(self.bone_index)
+
+        return {'FINISHED'}
+class OBJECT_PT_nla_alignment(Panel):
+    bl_space_type = 'NLA_EDITOR'
+    bl_region_type = 'UI'
+    bl_label = "Alignment"
+    
+
+    def draw(self, context):
+        #Q:   not in a poll() so it doesnt disappear on nla strip deselection (annoying)
+        if not context.selected_nla_strips:
+            return 
+
+        layout = self.layout
+        active_strip = get_active_strip()
+
+
+        box = layout.box()
+        for i,preblend in enumerate(active_strip.preblend_transforms):
+            box.prop(preblend,"location")
+            box.prop(preblend,"euler")
+            box.prop(preblend,"scale")
+
+            col = box.column(align=True)
+            row = col.row(align=True)
+            #todo: support for objects?
+            row.label(text="Bones")
+            row.operator(OBJECT_OT_nla_preblend_add_bone.bl_idname,text='',icon='ADD').preblend_index = i 
+            for j,bone in enumerate(preblend.bones):
+                row = box.row(align=True)
+                row.prop_search(bone,"name",context.active_object.data,"bones",text='')
+                op = row.operator(OBJECT_OT_nla_preblend_remove_bone.bl_idname,text='',icon='REMOVE')
+                op.preblend_index = i 
+                op.bone_index = j 
+
+
+classes = (
+    # Object Panels
+    OBJECT_PT_nla_alignment,
+    OBJECT_OT_nla_preblend_remove_bone,
+    OBJECT_OT_nla_preblend_add_bone,
+)
+
+if __name__ == "__main__":  # only for live edit.
+    from bpy.utils import register_class
+    for cls in classes:
+        register_class(cls)
diff --git a/source/blender/blenkernel/intern/anim_sys.c b/source/blender/blenkernel/intern/anim_sys.c
index a1d577259f7..3d709a41657 100644
--- a/source/blender/blenkernel/intern/anim_sys.c
+++ b/source/blender/blenkernel/intern/anim_sys.c
@@ -2996,6 +2996,18 @@ void nlastrip_evaluate(PointerRNA *ptr,
   /* Apply preblend transforms to each bone's raw snapshot values.  */
   Object *object = (Object *)ptr->owner_id;
   bPose *pose = object->pose;
+  /**
+   * Assumes preblend xformed bones are root bones with no parents. ( I think that would affect
+   * conversion to bone local space?). If it has an animated parent, then preblend xforms generally
+   * won't make sense anyways (not a usecase situation).
+   *
+   * Q: maybe the preblend xform should be stored per bone and already in local space?
+   *
+   * todo: make preblend xform UI in python... alot easier.
+   * todo: if strip has cycled, then apply preblend xform based on how far each bone moves per
+   * cycle. Probably need a toggle per preblend xform for whether cyclic offset if applied (no need
+   * to be per bone).
+   */
   LISTBASE_FOREACH (NlaStripPreBlendTransform *, preblend, &nes->strip->preblend_transforms) {
     float world[4][4];
     loc_eul_size_to_mat4(world, preblend->location, preblend->rotation_euler, preblend->scale);
diff --git a/source/blender/blenkernel/nla_private.h b/source/blender/blenkernel/nla_private.h
index b8c0dd5d9f1..420411b12f3 100644
--- a/source/blender/blenkernel/nla_private.h
+++ b/source/blender/blenkernel/nla_private.h
@@ -154,14 +154,6 @@ typedef struct NlaEvalData {
   NlaEvalSnapshot eval_snapshot;
 } NlaEvalData;
 
-typedef struct NlaPoseChannelPreBlend {
-  // char *bone_name;
-  NlaEvalChannel *location;
-  NlaEvalChannel *rotation;
-  NlaEvalChannel *scale;
-
-} NlaPoseChannelPreBlend;
-
 /* Information about the currently edited strip and ones below it for keyframing. */
 typedef struct NlaKeyframingContext {
   struct NlaKeyframingContext *next, *prev;