Synced animations looks good.

src/AnimNodes/BlendNode.h

@@ -9,11 +9,13 @@
 
 struct BlendNode : public AnimNode {
   BlendNode(AnimationController* animation_controller);
+
   virtual ~BlendNode() {}
 
   AnimNode* m_input_A;
   AnimNode* m_input_B;
   float m_weight;
+  bool m_sync_inputs;
 
   ozz::vector<ozz::math::SoaTransform> m_local_matrices_A;
   ozz::vector<ozz::math::SoaTransform> m_local_matrices_B;
@@ -22,9 +24,37 @@ struct BlendNode : public AnimNode {
     m_current_time = 0.f;
   }
 
-  virtual void Update(float dt) {
-    m_input_A->Update(dt);
-    m_input_B->Update(dt);
+  virtual void UpdateIsSynced(bool is_synced) override {
+    m_is_time_synced = is_synced;
+
+    if (m_sync_inputs) {
+      m_is_time_synced = true;
+    }
+
+    m_input_B->UpdateIsSynced(m_is_time_synced);
+    m_input_A->UpdateIsSynced(m_is_time_synced);
+  }
+
+  virtual void EvalAnimDuration() override {
+    if (m_is_time_synced) {
+      m_anim_duration = (1.0f - m_weight) * m_input_A->m_anim_duration + m_weight * m_input_B->m_anim_duration;
+    } else {
+      assert (false);
+    }
+  }
+
+  virtual void UpdateTime(float dt) {
+    if (m_is_time_synced) {
+      float current_time_absolute = m_current_time * m_anim_duration + dt;
+      m_current_time = fmodf(current_time_absolute / m_anim_duration, 1.0);
+
+      m_input_A->UpdateTime(m_current_time - m_input_A->m_current_time);
+      m_input_B->UpdateTime(m_current_time - m_input_B->m_current_time);
+    } else {
+      m_current_time += dt;
+      m_input_A->UpdateTime(dt);
+      m_input_B->UpdateTime(dt);
+    }
   }
 
   virtual void Evaluate(