advanced example

Content/Python/ue_workshop/sequence.py

@@ -1,4 +1,6 @@
 """Frame-based Sequencer helpers. Ranges are [start, end), rotations roll/pitch/yaw."""
+import math
+
 import unreal
 
 from .paths import GENERATED, slug
@@ -26,6 +28,7 @@ class Sequence:
         self.asset.set_playback_end(frames)
         self._bindings = {}
         self._transforms = {}
+        self._animations = {}
 
     def bind(self, actor):
         key = actor.get_path_name()
@@ -45,6 +48,82 @@ class Sequence:
         binding_id.set_editor_property("guid", binding.get_id())
         section.set_camera_binding_id(binding_id)
 
+    def _animation_blend(self, section, start, end, fade_in, fade_out):
+        # The skeletal animation section exposes its Weight channel to Python.
+        # add_key uses display frames and converts them to the sequence tick rate.
+        weight = section.get_all_channels()[0]
+        for key in weight.get_keys():
+            weight.remove_key(key)
+        weight.set_default(1.0)
+        if fade_in or fade_out:
+            keys = {start: 0.0 if fade_in else 1.0}
+            if fade_in:
+                keys[start + fade_in] = 1.0
+            if fade_out:
+                keys[end - fade_out] = 1.0
+                keys[end] = 0.0
+            for frame, value in sorted(keys.items()):
+                weight.add_key(unreal.FrameNumber(frame), value,
+                               interpolation=unreal.MovieSceneKeyInterpolation.LINEAR)
+
+    def animation(self, actor, clip=None, start=0, end=None, speed=1.0):
+        """Play/loop an imported clip over [start, end) in sequence frames.
+
+        clip is an alias from scene.skeletal_model(animations=...), an AnimSequence,
+        or None for the only embedded animation. Transform keys still move the parent.
+        Overlapping clips automatically crossfade over their entire shared range.
+        Add clips in timeline order; at most two clips can overlap at a time.
+        """
+        end = self.frames if end is None else end
+        if type(start) is not int or type(end) is not int or not 0 <= start < end <= self.frames:
+            raise ValueError(f"Zakres animacji: 0 <= start < end <= {self.frames}.")
+        if not isinstance(speed, (int, float)) or not math.isfinite(speed) or speed <= 0:
+            raise ValueError("Predkosc animacji musi byc dodatnia.")
+        entry = self.scene._skeletal_models.get(actor.get_path_name())
+        if entry is None:
+            raise ValueError("Animacja wymaga aktora utworzonego przez scene.skeletal_model().")
+        child, imported = entry
+        if clip is None:
+            if len(imported.animations) != 1:
+                raise ValueError("Wybierz animacje: " + ", ".join(imported.animations))
+            clip = next(iter(imported.animations.values()))
+        elif isinstance(clip, str):
+            if clip not in imported.animations:
+                raise ValueError("Nieznana animacja. Dostepne: " + ", ".join(imported.animations))
+            clip = imported.animations[clip]
+        if not isinstance(clip, unreal.AnimSequence):
+            raise TypeError("clip musi byc nazwa zaimportowanej animacji lub AnimSequence.")
+        if clip.get_editor_property("skeleton") != imported.mesh.get_editor_property("skeleton"):
+            raise ValueError("Animacja i model musza uzywac tego samego szkieletu.")
+        key = child.get_path_name()
+        sections = self._animations.setdefault(key, [])
+        overlaps = [old for old in sections if start < old[1] and old[0] < end]
+        previous = None
+        blend_frames = 0
+        if overlaps:
+            if (len(overlaps) != 1 or not overlaps[0][0] < start or
+                    overlaps[0][1] >= end or
+                    overlaps[0][0] + overlaps[0][4] > start):
+                raise ValueError("Dodawaj klipy w kolejnosci odtwarzania. Blend wymaga czesciowego "
+                                 "nakladania dwoch klipow, bez trzech jednoczesnych animacji.")
+            previous = overlaps[0]
+            blend_frames = previous[1] - start
+        track = sections[0][2] if sections else self.bind(child).add_track(unreal.MovieSceneSkeletalAnimationTrack)
+        section = track.add_section()
+        section.set_range(start, end)
+        params = section.get_editor_property("params")
+        params.set_editor_property("animation", clip)
+        rate = unreal.MovieSceneTimeWarpVariant()
+        rate.set_fixed_play_rate(float(speed))
+        params.set_editor_property("play_rate", rate)
+        params.set_editor_property("force_custom_mode", True)
+        section.set_editor_property("params", params)
+        self._animation_blend(section, start, end, blend_frames, 0)
+        if previous:
+            self._animation_blend(previous[3], previous[0], previous[1], previous[4], blend_frames)
+        sections.append((start, end, track, section, blend_frames))
+        return section
+
     def transform_key(self, actor, frame, location=None, rotation=None, scale=None, interpolation="linear"):
         if not isinstance(frame, int) or not 0 <= frame < self.frames:
             raise ValueError(f"Klatka musi nalezec do 0..{self.frames - 1}.")