Added marking of nodes active/inactive.

src/AnimGraphResource.cc

@@ -389,7 +389,20 @@ void AnimGraph::UpdateOrderedNodes() {
 void AnimGraph::MarkActiveNodes() {
   m_frame_counter++;
 
-  // TODO: start from output and trigger updating of the frame counter.
+  int first_node_index = getAnimNodeIndex(m_ordered_nodes[0]);
+  m_ordered_nodes[0]->m_frame_counter = m_frame_counter;
+  m_ordered_nodes[0]->UpdateActiveInputFrameCounters(m_node_inputs[first_node_index]);
+
+  for (size_t i = 1, n = m_ordered_nodes.size(); i < n; i++) {
+    AnimNode* node = m_ordered_nodes[i];
+    if (CheckIsNodeActive(node)) {
+      int node_index = getAnimNodeIndex(node);
+      node->UpdateActiveInputFrameCounters(m_node_inputs[node_index]);
+    } else {
+      // Avoid active frame counter overrun.
+      node->m_frame_counter = m_frame_counter - 1;
+    }
+  }
 }
 
 void* AnimGraph::GetOutput(const std::string& name) const {

src/AnimGraphResource.h

@@ -319,6 +319,26 @@ struct Blend2Node : public AnimNode {
   AnimData* m_output = nullptr;
   float m_blend_weight = 0.f;
   bool m_sync_blend = false;
+
+
+  virtual void UpdateActiveInputFrameCounters (const std::vector<AnimNodeInput>& inputs) override {
+    for (size_t i = 0, n = inputs.size(); i < n; i++) {
+      AnimNode* input_node = inputs[i].m_node;
+      if (input_node == nullptr) {
+        continue;
+      }
+
+      if (inputs[i].m_input_name == "Input0" && m_blend_weight < 0.999) {
+        input_node->m_frame_counter = m_frame_counter;
+        continue;
+      }
+
+      if (inputs[i].m_input_name == "Input1" && m_blend_weight > 0.001) {
+        input_node->m_frame_counter = m_frame_counter;
+        continue;
+      }
+    }
+  }
 };
 
 template <>
@@ -532,14 +552,13 @@ struct AnimGraph {
 
   void UpdateOrderedNodes();
   void MarkActiveNodes();
-  bool CheckNodeActive(int node_index) {
-    assert(node_index < m_nodes.size());
-    return m_nodes[node_index]->m_frame_counter == m_frame_counter;
+  bool CheckIsNodeActive(AnimNode* node) {
+    return node->m_frame_counter == m_frame_counter;
   }
   void UpdateTime(float dt);
   void Evaluate();
 
-  int m_frame_counter;
+  int m_frame_counter = 0;
   AnimData m_local_transforms;
 
   std::vector<AnimNode*> m_nodes;