Synced animations looks good.

src/AnimNodes/AnimSamplerNode.h

@@ -10,26 +10,47 @@
 struct AnimSamplerNode : public AnimNode {
   AnimSamplerNode(AnimationController* animation_controller)
       : AnimNode(animation_controller),
-        m_anim_ratio(0.f),
-        m_override_ratio(false){};
+        m_override_ratio(false),
+        m_anim_ratio(0.f) {
+    assert(m_current_time < 100.0f);
+    m_anim_node_type = AnimNodeType::AnimSampler;
+  };
   virtual ~AnimSamplerNode() {}
 
   ozz::animation::Animation* m_animation;
 
-  float m_anim_ratio;
   bool m_override_ratio;
+  float m_anim_ratio;
 
   ozz::animation::SamplingCache m_sampling_cache;
 
   void SetAnimation(ozz::animation::Animation* animation);
 
-  virtual void Update(float dt) override {
+  virtual void UpdateIsSynced(bool is_synced) override {
+    m_is_time_synced = is_synced;
+  }
+
+  virtual void EvalAnimDuration() override {
+    m_anim_duration = m_animation->duration();
+  }
+
+  virtual void UpdateTime(float dt) override {
     m_current_time += dt;
     if (!m_override_ratio) {
-      const float duration = m_animation->duration();
-      m_anim_ratio = fmodf((float)m_current_time / duration, 1.0f);
+      if (m_is_time_synced) {
+        m_anim_ratio = fmodf((float)m_current_time, 1.0f);
+        m_current_time = m_anim_ratio;
+      } else {
+        const float duration = m_animation->duration();
+        m_anim_ratio = fmodf((float)m_current_time / duration, 1.0f);
+      }
+    }
+
+    if (m_anim_ratio < 0.f) {
+      m_anim_ratio += 1.0f;
     }
   }
+
   virtual void Evaluate(
       ozz::vector<ozz::math::SoaTransform>* local_matrices) override;