Added support of time updates for simple embedded graphs.

src/AnimGraph/AnimGraphBlendTree.cc

@@ -32,8 +32,12 @@ void AnimGraphBlendTree::UpdateOrderedNodesRecursive(int node_index) {
   const std::vector<AnimGraphConnection>& node_input_connections =
       m_node_input_connections[node_index];
   for (size_t i = 0, n = node_input_connections.size(); i < n; i++) {
+    if (node_input_connections[i].m_crosses_hierarchy) {
+      continue;
+    }
+
     int input_node_index =
-        GetAnimNodeIndex(node_input_connections.at(i).m_source_node);
+        GetAnimNodeIndex(node_input_connections[i].m_source_node);
 
     if (input_node_index == 1) {
       continue;
@@ -58,9 +62,11 @@ void AnimGraphBlendTree::UpdateOrderedNodesRecursive(int node_index) {
   }
 }
 
-void AnimGraphBlendTree::MarkActiveInputs() {
+void AnimGraphBlendTree::MarkActiveInputs(const std::vector<AnimGraphConnection>& input_connections) {
   for (size_t i = 0, n = m_nodes.size(); i < n; i++) {
-    m_nodes[i]->m_state = AnimNodeEvalState::Deactivated;
+    if (m_nodes[i]->m_tick_number != m_tick_number) {
+      m_nodes[i]->m_state = AnimNodeEvalState::Deactivated;
+    }
   }
 
   const std::vector<AnimGraphConnection>& graph_output_inputs =
@@ -69,15 +75,16 @@ void AnimGraphBlendTree::MarkActiveInputs() {
     const AnimGraphConnection& graph_input = graph_output_inputs[i];
     AnimNode* node = graph_input.m_source_node;
     if (node != nullptr) {
+      node->m_tick_number = m_tick_number;
       node->m_state = AnimNodeEvalState::Activated;
     }
   }
 
-  for (size_t i = m_eval_ordered_nodes.size() - 1; i >= 0; i--) {
+  for (int i = m_eval_ordered_nodes.size() - 1; i >= 0; i--) {
     AnimNode* node = m_eval_ordered_nodes[i];
-    if (checkIsNodeActive(node)) {
+    if (CheckIsNodeActive(node)) {
-      node->MarkActiveInputs();
       size_t node_index = GetAnimNodeIndex(node);
+      node->MarkActiveInputs(m_node_input_connections[node_index]);
 
       // Non-animation data inputs are always active.
       for (size_t j = 0, nj = m_node_input_connections[node_index].size();
@@ -95,14 +102,14 @@ void AnimGraphBlendTree::MarkActiveInputs() {
   }
 }
 
-void AnimGraphBlendTree::CalcSyncTrack() {
+void AnimGraphBlendTree::CalcSyncTrack(const std::vector<AnimGraphConnection>& input_connections) {
   for (size_t i = m_eval_ordered_nodes.size() - 1; i >= 0; i--) {
     AnimNode* node = m_eval_ordered_nodes[i];
     if (node->m_state == AnimNodeEvalState::Deactivated) {
       continue;
     }
 
-    node->CalcSyncTrack();
+    node->CalcSyncTrack(m_node_input_connections[GetAnimNodeIndex(node)]);
   }
 }
 
@@ -113,35 +120,21 @@ void AnimGraphBlendTree::UpdateTime(float time_last, float time_now) {
       m_node_input_connections[0];
   for (size_t i = 0, n = graph_output_inputs.size(); i < n; i++) {
     AnimNode* node = graph_output_inputs[i].m_source_node;
-    if (node != nullptr) {
+    if (node != nullptr && node->m_state != AnimNodeEvalState::TimeUpdated) {
-      node->UpdateTime(node->m_time_now, node->m_time_now + dt);
+      node->UpdateTime(time_last, time_now);
     }
   }
 
-  for (size_t i = m_eval_ordered_nodes.size() - 1; i > 0; --i) {
+  for (int i = m_eval_ordered_nodes.size() - 1; i >= 0; --i) {
     AnimNode* node = m_eval_ordered_nodes[i];
     if (node->m_state != AnimNodeEvalState::TimeUpdated) {
       continue;
     }
 
-    size_t node_index = GetAnimNodeIndex(node);
+    PropagateTimeToNodeInputs(node);
-    float node_time_now = node->m_time_now;
-    float node_time_last = node->m_time_last;
-
-    const std::vector<AnimGraphConnection>& node_input_connections =
-        m_node_input_connections[node_index];
-    for (size_t i = 0, n = node_input_connections.size(); i < n; i++) {
-      AnimNode* input_node = node_input_connections[i].m_source_node;
-
-      // Only propagate time updates via animation sockets.
-      if (input_node != nullptr
-          && node_input_connections[i].m_target_socket.m_type
-                 == SocketType::SocketTypeAnimation
-          && input_node->m_state == AnimNodeEvalState::Activated) {
-        input_node->UpdateTime(node_time_last, node_time_now);
-      }
-    }
   }
+
+  m_state = AnimNodeEvalState::TimeUpdated;
 }
 
 void AnimGraphBlendTree::Evaluate(AnimGraphContext& context) {
@@ -156,6 +149,27 @@ void AnimGraphBlendTree::Evaluate(AnimGraphContext& context) {
   }
 }
 
+void AnimGraphBlendTree::PropagateTimeToNodeInputs(const AnimNode* node) {
+  size_t node_index = GetAnimNodeIndex(node);
+
+  float node_time_now = node->m_time_now;
+  float node_time_last = node->m_time_last;
+
+  const std::vector<AnimGraphConnection>& node_input_connections =
+      m_node_input_connections[node_index];
+  for (size_t i = 0, n = node_input_connections.size(); i < n; i++) {
+    AnimNode* input_node = node_input_connections[i].m_source_node;
+
+    // Only propagate time updates via animation sockets.
+    if (input_node != nullptr
+        && node_input_connections[i].m_target_socket.m_type
+               == SocketType::SocketTypeAnimation
+        && input_node->m_state == AnimNodeEvalState::Activated) {
+      input_node->UpdateTime(node_time_last, node_time_now);
+    }
+  }
+}
+
 Socket* AnimGraphBlendTree::GetInputSocket(const std::string& name) {
   for (size_t i = 0, n = m_node_output_connections[1].size(); i < n; i++) {
     AnimGraphConnection& connection = m_node_output_connections[1][i];

src/AnimGraph/AnimGraphBlendTree.h

@@ -31,13 +31,19 @@ struct AnimGraphBlendTree : public AnimNode {
 
   ~AnimGraphBlendTree() override { dealloc(); }
 
+  void StartUpdateTick() { m_tick_number++; }
+
   // AnimNode overrides
   bool Init(AnimGraphContext& context) override;
-  void MarkActiveInputs() override;
+  void MarkActiveInputs(
-  void CalcSyncTrack() override;
+      const std::vector<AnimGraphConnection>& input_connections) override;
+  void CalcSyncTrack(
+      const std::vector<AnimGraphConnection>& input_connections) override;
   void UpdateTime(float time_last, float time_now) override;
   void Evaluate(AnimGraphContext& context) override;
 
+  void PropagateTimeToNodeInputs(const AnimNode* node);
+
   void dealloc() {
     for (size_t i = 0; i < m_animdata_blocks.size(); i++) {
       m_animdata_blocks[i]->m_local_matrices.vector::~vector();
@@ -62,8 +68,8 @@ struct AnimGraphBlendTree : public AnimNode {
 
   void UpdateOrderedNodes();
   void UpdateOrderedNodesRecursive(int node_index);
-  bool checkIsNodeActive(AnimNode* node) {
+  bool CheckIsNodeActive(AnimNode* node) {
-    return node->m_state != AnimNodeEvalState::Deactivated;
+    return node->m_tick_number == m_tick_number;
   }
 
   void ResetNodeStates() {
@@ -117,9 +123,10 @@ struct AnimGraphBlendTree : public AnimNode {
       if (graph_output_connection.m_target_socket.m_name == name) {
         if (graph_output_connection.m_source_node == m_nodes[1]
             && graph_output_connection.m_target_node == m_nodes[0]) {
-          std::cerr << "Error: cannot set output for direct graph input to graph "
+          std::cerr
-                       "output connections. Use GetOutptPtr for output instead!"
+              << "Error: cannot set output for direct graph input to graph "
-                    << std::endl;
+                 "output connections. Use GetOutptPtr for output instead!"
+              << std::endl;
 
           return;
         }
@@ -130,14 +137,18 @@ struct AnimGraphBlendTree : public AnimNode {
         // Make sure all other output connections of this pin use the same output pointer
         int source_node_index =
             GetAnimNodeIndex(graph_output_connection.m_source_node);
-        for (int j = 0; j < m_node_output_connections[source_node_index].size(); j++) {
+        for (int j = 0; j < m_node_output_connections[source_node_index].size();
-          const AnimGraphConnection& source_output_connection = m_node_output_connections[source_node_index][j];
+             j++) {
+          const AnimGraphConnection& source_output_connection =
+              m_node_output_connections[source_node_index][j];
           if (source_output_connection.m_target_node == m_nodes[0]) {
             continue;
           }
 
-          if (source_output_connection.m_source_socket.m_name == graph_output_connection.m_source_socket.m_name) {
+          if (source_output_connection.m_source_socket.m_name
-            *source_output_connection.m_target_socket.m_reference.ptr_ptr = value_ptr;
+              == graph_output_connection.m_source_socket.m_name) {
+            *source_output_connection.m_target_socket.m_reference.ptr_ptr =
+                value_ptr;
           }
         }
       }
@@ -159,7 +170,8 @@ struct AnimGraphBlendTree : public AnimNode {
       const AnimGraphConnection& graph_output_connection =
           m_node_input_connections[0][i];
       if (graph_output_connection.m_target_socket.m_name == name) {
-        return static_cast<float*>(*graph_output_connection.m_source_socket.m_reference.ptr_ptr);
+        return static_cast<float*>(
+            *graph_output_connection.m_source_socket.m_reference.ptr_ptr);
       }
     }
 
@@ -219,7 +231,7 @@ struct AnimGraphBlendTree : public AnimNode {
     return nullptr;
   }
 
-  size_t GetAnimNodeIndex(AnimNode* node) {
+  size_t GetAnimNodeIndex(const AnimNode* node) const {
     for (size_t i = 0; i < m_nodes.size(); i++) {
       if (m_nodes[i] == node) {
         return i;
@@ -230,5 +242,14 @@ struct AnimGraphBlendTree : public AnimNode {
   }
 };
 
+//
+// BlendTreeSocketNode
+//
+struct BlendTreeSocketNode : public AnimNode {};
+
+template <>
+struct NodeDescriptor<BlendTreeSocketNode> : public NodeDescriptorBase {
+  NodeDescriptor(BlendTreeSocketNode* node_) {}
+};
 
 #endif  //ANIMTESTBED_ANIMGRAPHBLENDTREE_H

src/AnimGraph/AnimGraphData.h

@@ -265,6 +265,7 @@ struct AnimGraphConnection {
   Socket m_source_socket;
   AnimNode* m_target_node = nullptr;
   Socket m_target_socket;
+  bool m_crosses_hierarchy = false;
 };
 
 

src/AnimGraph/AnimGraphEditor.cc

@@ -7,14 +7,14 @@
 #include <sstream>
 
 #include "3rdparty/imgui-node-editor/imgui_node_editor.h"
-#include "AnimGraphBlendTreeResource.h"
+#include "AnimGraphResource.h"
 #include "SkinnedMesh.h"
 #include "imgui.h"
 #include "imnodes.h"
 #include "misc/cpp/imgui_stdlib.h"
 
-static AnimGraphBlendTreeResource sGraphGresource =
+static AnimGraphResource sGraphGresource =
-    AnimGraphBlendTreeResource();
+    AnimGraphResource();
 static bool sGraphLoadedThisFrame = false;
 
 ImNodesPinShape sGetSocketShapeFromSocketType(const SocketType& socket_type) {
@@ -59,13 +59,13 @@ void NodeSocketEditor(Socket& socket) {
 }
 
 void RemoveConnectionsForSocket(
-    AnimGraphBlendTreeResource& graph_resource,
+    AnimGraphResource& graph_resource,
     AnimNodeResource& node_resource,
     Socket& socket) {
-  std::vector<AnimGraphConnectionResource>::iterator iter =
+  std::vector<BlendTreeConnectionResource>::iterator iter =
-      graph_resource.m_connections.begin();
+      graph_resource.m_blend_tree_resource.m_connections.begin();
 
-  while (iter != graph_resource.m_connections.end()) {
+  while (iter != graph_resource.m_blend_tree_resource.m_connections.end()) {
     // TODO adjust for refactor
     assert(false);
 

src/AnimGraph/AnimGraphNodes.cc

@@ -3,13 +3,13 @@
 //
 
 #include "AnimGraphNodes.h"
-#include "AnimGraphBlendTree.h"
 
-#include "ozz/base/log.h"
+#include "AnimGraphBlendTree.h"
-#include "ozz/animation/runtime/blending_job.h"
 #include "ozz/animation/runtime/animation.h"
+#include "ozz/animation/runtime/blending_job.h"
 #include "ozz/base/io/archive.h"
 #include "ozz/base/io/stream.h"
+#include "ozz/base/log.h"
 
 AnimNode* AnimNodeFactory(const std::string& name) {
   AnimNode* result;
@@ -24,7 +24,7 @@ AnimNode* AnimNodeFactory(const std::string& name) {
   } else if (name == "BlendTree") {
     result = new AnimGraphBlendTree;
   } else if (name == "BlendTreeSockets") {
-    result = new BlendTreeNode;
+    result = new BlendTreeSocketNode;
   } else if (name == "MathAddNode") {
     result = new MathAddNode;
   } else if (name == "MathFloatToVec3Node") {
@@ -42,12 +42,39 @@ AnimNode* AnimNodeFactory(const std::string& name) {
   return nullptr;
 }
 
+NodeDescriptorBase* AnimNodeDescriptorFactory(
+    const std::string& node_type_name,
+    AnimNode* node) {
+  if (node_type_name == "Blend2") {
+    return CreateNodeDescriptor<Blend2Node>(node);
+  } else if (node_type_name == "SpeedScale") {
+    return CreateNodeDescriptor<SpeedScaleNode>(node);
+  } else if (node_type_name == "AnimSampler") {
+    return CreateNodeDescriptor<AnimSamplerNode>(node);
+  } else if (node_type_name == "LockTranslationNode") {
+    return CreateNodeDescriptor<LockTranslationNode>(node);
+  } else if (node_type_name == "BlendTree") {
+    return CreateNodeDescriptor<BlendTreeSocketNode>(node);
+  } else if (node_type_name == "BlendTreeSockets") {
+    return CreateNodeDescriptor<BlendTreeSocketNode>(node);
+  } else if (node_type_name == "MathAddNode") {
+    return CreateNodeDescriptor<MathAddNode>(node);
+  } else if (node_type_name == "MathFloatToVec3Node") {
+    return CreateNodeDescriptor<MathFloatToVec3Node>(node);
+  } else if (node_type_name == "ConstScalarNode") {
+    return CreateNodeDescriptor<ConstScalarNode>(node);
+  } else {
+    std::cerr << "Invalid node type name " << node_type_name << "."
+              << std::endl;
+  }
+  return nullptr;
+}
 
 void Blend2Node::Evaluate(AnimGraphContext& context) {
-  assert (i_input0 != nullptr);
+  assert(i_input0 != nullptr);
-  assert (i_input1 != nullptr);
+  assert(i_input1 != nullptr);
-  assert (i_blend_weight != nullptr);
+  assert(i_blend_weight != nullptr);
-  assert (o_output != nullptr);
+  assert(o_output != nullptr);
 
   // perform blend
   ozz::animation::BlendingJob::Layer layers[2];
@@ -71,12 +98,10 @@ void Blend2Node::Evaluate(AnimGraphContext& context) {
 //
 // AnimSamplerNode
 //
-AnimSamplerNode::~AnimSamplerNode() noexcept {
+AnimSamplerNode::~AnimSamplerNode() noexcept { m_animation = nullptr; }
-  m_animation = nullptr;
-}
 
 bool AnimSamplerNode::Init(AnimGraphContext& context) {
-  assert (m_animation == nullptr);
+  assert(m_animation == nullptr);
   assert(!m_filename.empty());
 
   AnimGraphContext::AnimationFileMap::const_iterator animation_map_iter;
@@ -103,14 +128,14 @@ bool AnimSamplerNode::Init(AnimGraphContext& context) {
     context.m_animation_map[m_filename] = m_animation;
   }
 
-  assert (context.m_skeleton != nullptr);
+  assert(context.m_skeleton != nullptr);
   m_sampling_context.Resize(context.m_skeleton->num_joints());
 
   return true;
 }
 
 void AnimSamplerNode::Evaluate(AnimGraphContext& context) {
-  assert (o_output != nullptr);
+  assert(o_output != nullptr);
 
   ozz::animation::SamplingJob sampling_job;
   sampling_job.animation = m_animation;

src/AnimGraph/AnimGraphNodes.h

@@ -7,23 +7,13 @@
 
 #include <vector>
 
-#include "AnimNode.h"
 #include "AnimGraphData.h"
+#include "AnimNode.h"
 #include "SyncTrack.h"
 #include "ozz/animation/runtime/sampling_job.h"
 
 struct AnimNode;
 
-//
-// BlendTreeNode
-//
-struct BlendTreeNode : public AnimNode {};
-
-template <>
-struct NodeDescriptor<BlendTreeNode> : public NodeDescriptorBase {
-  NodeDescriptor(BlendTreeNode* node_) {}
-};
-
 //
 // Blend2Node
 //
@@ -34,8 +24,9 @@ struct Blend2Node : public AnimNode {
   float* i_blend_weight = nullptr;
   bool m_sync_blend = false;
 
-  virtual void MarkActiveInputs() override {
+  void MarkActiveInputs(
-    for (const auto & input : m_inputs) {
+      const std::vector<AnimGraphConnection>& input_connections) override {
+    for (const auto& input : input_connections) {
       AnimNode* input_node = input.m_source_node;
       if (input_node == nullptr) {
         continue;
@@ -53,7 +44,7 @@ struct Blend2Node : public AnimNode {
     }
   }
 
-  virtual void Evaluate(AnimGraphContext& context) override;
+  void Evaluate(AnimGraphContext& context) override;
 };
 
 template <>
@@ -80,7 +71,6 @@ struct NodeDescriptor<Blend2Node> : public NodeDescriptorBase {
   }
 };
 
-
 //
 // SpeedScaleNode
 //
@@ -96,8 +86,8 @@ struct SpeedScaleNode : public AnimNode {
   }
 
   void Evaluate(AnimGraphContext& context) override {
-    assert (i_input != nullptr);
+    assert(i_input != nullptr);
-    assert (o_output != nullptr);
+    assert(o_output != nullptr);
 
     o_output->m_local_matrices = i_input->m_local_matrices;
   };
@@ -116,7 +106,6 @@ struct NodeDescriptor<SpeedScaleNode> : public NodeDescriptorBase {
   }
 };
 
-
 //
 // AnimSamplerNode
 //
@@ -172,7 +161,6 @@ struct NodeDescriptor<LockTranslationNode> : public NodeDescriptorBase {
   }
 };
 
-
 //
 // ConstScalarNode
 //
@@ -180,9 +168,7 @@ struct ConstScalarNode : public AnimNode {
   float* o_value = nullptr;
   float value = 0.f;
 
-  virtual void Evaluate(AnimGraphContext& context){
+  virtual void Evaluate(AnimGraphContext& context) { *o_value = value; };
-    *o_value = value;
-  };
 };
 
 template <>
@@ -193,7 +179,6 @@ struct NodeDescriptor<ConstScalarNode> : public NodeDescriptorBase {
   }
 };
 
-
 //
 // MathAddNode
 //
@@ -203,8 +188,8 @@ struct MathAddNode : public AnimNode {
   float* o_output = nullptr;
 
   void Evaluate(AnimGraphContext& context) override {
-    assert (i_input0 != nullptr);
+    assert(i_input0 != nullptr);
-    assert (i_input1 != nullptr);
+    assert(i_input1 != nullptr);
 
     *o_output = *i_input0 + *i_input1;
   }
@@ -229,9 +214,9 @@ struct MathFloatToVec3Node : public AnimNode {
   Vec3* o_output = nullptr;
 
   void Evaluate(AnimGraphContext& context) override {
-    assert (i_input0 != nullptr);
+    assert(i_input0 != nullptr);
-    assert (i_input1 != nullptr);
+    assert(i_input1 != nullptr);
-    assert (i_input2 != nullptr);
+    assert(i_input2 != nullptr);
 
     o_output->v[0] = *i_input0;
     o_output->v[1] = *i_input1;
@@ -249,35 +234,10 @@ struct NodeDescriptor<MathFloatToVec3Node> : public NodeDescriptorBase {
   }
 };
 
-
 AnimNode* AnimNodeFactory(const std::string& name);
 
-static inline NodeDescriptorBase* AnimNodeDescriptorFactory(
+NodeDescriptorBase* AnimNodeDescriptorFactory(
     const std::string& node_type_name,
-    AnimNode* node) {
+    AnimNode* node);
-  if (node_type_name == "Blend2") {
-    return CreateNodeDescriptor<Blend2Node>(node);
-  } else if (node_type_name == "SpeedScale") {
-    return CreateNodeDescriptor<SpeedScaleNode>(node);
-  } else if (node_type_name == "AnimSampler") {
-    return CreateNodeDescriptor<AnimSamplerNode>(node);
-  } else if (node_type_name == "LockTranslationNode") {
-    return CreateNodeDescriptor<LockTranslationNode>(node);
-  } else if (node_type_name == "BlendTree") {
-    return CreateNodeDescriptor<BlendTreeNode>(node);
-  } else if (node_type_name == "BlendTreeSockets") {
-    return CreateNodeDescriptor<BlendTreeNode>(node);
-  } else if (node_type_name == "MathAddNode") {
-    return CreateNodeDescriptor<MathAddNode>(node);
-  } else if (node_type_name == "MathFloatToVec3Node") {
-    return CreateNodeDescriptor<MathFloatToVec3Node>(node);
-  } else if (node_type_name == "ConstScalarNode") {
-    return CreateNodeDescriptor<ConstScalarNode>(node);
-  } else {
-    std::cerr << "Invalid node type name " << node_type_name << "."
-              << std::endl;
-  }
-  return nullptr;
-}
 
 #endif  //ANIMTESTBED_ANIMGRAPHNODES_H

src/AnimGraph/AnimGraphResource.cc

@@ -8,15 +8,17 @@
 #include <fstream>
 
 #include "3rdparty/json/json.hpp"
-
 #include "AnimGraphBlendTree.h"
 #include "AnimGraphNodes.h"
 
 using json = nlohmann::json;
 
 // forward declarations
-static json sAnimGraphResourceBlendTreeToJson(const AnimGraphResource& anim_graph_resource);
+static json sAnimGraphResourceBlendTreeToJson(
-static bool sAnimGraphResourceBlendTreeFromJson(const json& json_data, AnimGraphResource* result_graph_resource);
+    const AnimGraphResource& anim_graph_resource);
+static bool sAnimGraphResourceBlendTreeFromJson(
+    const json& json_data,
+    AnimGraphResource* result_graph_resource);
 
 //
 // Socket <-> json
@@ -143,7 +145,6 @@ json sAnimGraphNodeToJson(
   }
 
   if (node->m_node_type_name == "BlendTree") {
-
   }
 
   for (const auto& socket : node->m_socket_accessor->m_inputs) {
@@ -175,7 +176,6 @@ json sAnimGraphNodeToJson(
 AnimNodeResource* sAnimGraphNodeFromJson(
     const json& json_node,
     size_t node_index) {
-
   std::string node_type = json_node["node_type"];
 
   if (node_type == "BlendTree") {
@@ -247,20 +247,23 @@ BlendTreeConnectionResource sAnimGraphConnectionFromJson(
   return connection;
 }
 
-static json sAnimGraphResourceBlendTreeToJson(const AnimGraphResource& anim_graph_resource) {
+static json sAnimGraphResourceBlendTreeToJson(
+    const AnimGraphResource& anim_graph_resource) {
   json result;
 
   result["name"] = anim_graph_resource.m_name;
   result["type"] = "AnimNodeResource";
   result["node_type"] = "BlendTree";
 
-  const BlendTreeResource& blend_tree_resource = anim_graph_resource.m_blend_tree_resource;
+  const BlendTreeResource& blend_tree_resource =
+      anim_graph_resource.m_blend_tree_resource;
 
   for (size_t i = 0; i < blend_tree_resource.m_nodes.size(); i++) {
     const AnimNodeResource* node = blend_tree_resource.m_nodes[i];
 
     if (node->m_node_type_name == "BlendTree") {
-      const AnimGraphResource* graph_resource = dynamic_cast<const AnimGraphResource*>(node);
+      const AnimGraphResource* graph_resource =
+          dynamic_cast<const AnimGraphResource*>(node);
       result["nodes"][i] = sAnimGraphResourceBlendTreeToJson(*graph_resource);
     } else {
       result["nodes"][i] =
@@ -276,8 +279,7 @@ static json sAnimGraphResourceBlendTreeToJson(const AnimGraphResource& anim_grap
 
   // Graph inputs and outputs
   {
-    const AnimNodeResource* graph_output_node =
+    const AnimNodeResource* graph_output_node = blend_tree_resource.m_nodes[0];
-        blend_tree_resource.m_nodes[0];
     const std::vector<Socket> graph_inputs =
         graph_output_node->m_socket_accessor->m_inputs;
     for (size_t i = 0; i < graph_inputs.size(); i++) {
@@ -294,8 +296,11 @@ static json sAnimGraphResourceBlendTreeToJson(const AnimGraphResource& anim_grap
   return result;
 }
 
-static bool sAnimGraphResourceBlendTreeFromJson(const json& json_data, AnimGraphResource* result_graph_resource) {
+static bool sAnimGraphResourceBlendTreeFromJson(
-  BlendTreeResource& blend_tree_resource = result_graph_resource->m_blend_tree_resource;
+    const json& json_data,
+    AnimGraphResource* result_graph_resource) {
+  BlendTreeResource& blend_tree_resource =
+      result_graph_resource->m_blend_tree_resource;
 
   result_graph_resource->m_graph_type_name = "BlendTree";
   result_graph_resource->m_node_type_name = "BlendTree";
@@ -351,14 +356,14 @@ static bool sAnimGraphResourceBlendTreeFromJson(const json& json_data, AnimGraph
   return true;
 }
 
-bool BlendTreeResource::ConnectSockets (
+bool BlendTreeResource::ConnectSockets(
     const AnimNodeResource* source_node,
     const std::string& source_socket_name,
     const AnimNodeResource* target_node,
     const std::string& target_socket_name) {
   size_t source_node_index = GetNodeIndex(source_node);
   size_t target_node_index = GetNodeIndex(target_node);
-  
+
   if (source_node_index >= m_nodes.size()
       || target_node_index >= m_nodes.size()) {
     std::cerr << "Cannot connect nodes: could not find nodes." << std::endl;
@@ -369,23 +374,29 @@ bool BlendTreeResource::ConnectSockets (
   Socket* target_socket;
 
   if (target_node->m_node_type_name == "BlendTree") {
-    const AnimGraphResource* target_graph_resource = dynamic_cast<const AnimGraphResource*>(target_node);
+    const AnimGraphResource* target_graph_resource =
-    AnimNodeResource* graph_output_node = target_graph_resource->m_blend_tree_resource.GetGraphInputNode();
+        dynamic_cast<const AnimGraphResource*>(target_node);
-    target_socket = graph_output_node->m_socket_accessor->GetOutputSocket(target_socket_name.c_str());
+    AnimNodeResource* graph_output_node =
+        target_graph_resource->m_blend_tree_resource.GetGraphInputNode();
+    target_socket = graph_output_node->m_socket_accessor->GetOutputSocket(
+        target_socket_name.c_str());
   } else {
-    target_socket =
+    target_socket = target_node->m_socket_accessor->GetInputSocket(
-        target_node->m_socket_accessor->GetInputSocket(target_socket_name.c_str());
+        target_socket_name.c_str());
   }
 
   if (source_node->m_node_type_name == "BlendTree") {
-    const AnimGraphResource* source_graph_resource = dynamic_cast<const AnimGraphResource*>(source_node);
+    const AnimGraphResource* source_graph_resource =
-    AnimNodeResource* graph_output_node = source_graph_resource->m_blend_tree_resource.GetGraphOutputNode();
+        dynamic_cast<const AnimGraphResource*>(source_node);
-    source_socket = graph_output_node->m_socket_accessor->GetInputSocket(source_socket_name.c_str());
+    AnimNodeResource* graph_output_node =
+        source_graph_resource->m_blend_tree_resource.GetGraphOutputNode();
+    source_socket = graph_output_node->m_socket_accessor->GetInputSocket(
+        source_socket_name.c_str());
   } else {
-    source_socket =
+    source_socket = source_node->m_socket_accessor->GetOutputSocket(
-        source_node->m_socket_accessor->GetOutputSocket(source_socket_name.c_str());
+        source_socket_name.c_str());
   }
-  
+
   if (source_socket == nullptr || target_socket == nullptr) {
     std::cerr << "Cannot connect nodes: could not find sockets." << std::endl;
     return false;
@@ -443,7 +454,8 @@ bool AnimGraphResource::SaveToFile(const char* filename) const {
     return SaveStateMachineResourceToFile(filename);
   }
 
-  std::cerr << "Invalid AnimGraphResource type: " << m_graph_type_name << "." << std::endl;
+  std::cerr << "Invalid AnimGraphResource type: " << m_graph_type_name << "."
+            << std::endl;
 
   return false;
 }
@@ -452,8 +464,7 @@ bool AnimGraphResource::SaveBlendTreeResourceToFile(
     const char* filename) const {
   json result;
 
-  result = sAnimGraphResourceBlendTreeToJson(
+  result = sAnimGraphResourceBlendTreeToJson(*this);
-      *this);
 
   std::ofstream output_file;
   output_file.open(filename);
@@ -466,14 +477,18 @@ bool AnimGraphResource::SaveBlendTreeResourceToFile(
 void AnimGraphResource::CreateBlendTreeInstance(
     AnimGraphBlendTree& result) const {
   if (m_node_type_name != "BlendTree") {
-    std::cerr << "Invalid AnimGraphResource. Expected type 'BlendTree' but got '"
+    std::cerr
-    << m_graph_type_name << "'." << std::endl;
+        << "Invalid AnimGraphResource. Expected type 'BlendTree' but got '"
+        << m_graph_type_name << "'." << std::endl;
     return;
   }
 
+  result.m_name = m_name;
+
   CreateBlendTreeRuntimeNodeInstances(result);
   PrepareBlendTreeIOData(result);
   SetRuntimeNodeProperties(result);
+  CreateBlendTreeConnectionInstances(result);
 
   result.UpdateOrderedNodes();
   result.ResetNodeStates();
@@ -485,14 +500,19 @@ void AnimGraphResource::CreateBlendTreeRuntimeNodeInstances(
     AnimNode* node = AnimNodeFactory(node_resource->m_node_type_name);
 
     if (node_resource->m_node_type_name == "BlendTree") {
-      AnimGraphResource* embedded_blend_tree_resource = dynamic_cast<AnimGraphResource*>(node_resource);
+      AnimGraphResource* embedded_blend_tree_resource =
+          dynamic_cast<AnimGraphResource*>(node_resource);
       assert(embedded_blend_tree_resource != nullptr);
-      AnimGraphBlendTree* embedded_blend_tree = dynamic_cast<AnimGraphBlendTree*>(node);
+      AnimGraphBlendTree* embedded_blend_tree =
+          dynamic_cast<AnimGraphBlendTree*>(node);
       assert(embedded_blend_tree != nullptr);
 
-      embedded_blend_tree_resource->CreateBlendTreeInstance(*embedded_blend_tree);
+      embedded_blend_tree_resource->CreateBlendTreeInstance(
-      embedded_blend_tree_resource->m_socket_accessor->m_inputs = embedded_blend_tree->m_node_descriptor->m_outputs;
+          *embedded_blend_tree);
-      embedded_blend_tree_resource->m_socket_accessor->m_outputs = embedded_blend_tree->m_node_descriptor->m_inputs;
+      embedded_blend_tree_resource->m_socket_accessor->m_inputs =
+          embedded_blend_tree->m_node_descriptor->m_outputs;
+      embedded_blend_tree_resource->m_socket_accessor->m_outputs =
+          embedded_blend_tree->m_node_descriptor->m_inputs;
     }
 
     node->m_name = node_resource->m_name;
@@ -574,16 +594,20 @@ void AnimGraphResource::PrepareBlendTreeIOData(
     instance.m_connection_data_storage = new char[connection_data_storage_size];
     memset(instance.m_connection_data_storage, 0, connection_data_storage_size);
   }
+}
 
+void AnimGraphResource::CreateBlendTreeConnectionInstances(
+    AnimGraphBlendTree& instance) const {
   std::vector<NodeDescriptorBase*> instance_node_descriptors(
       m_blend_tree_resource.m_nodes.size(),
       nullptr);
   for (int i = 0; i < m_blend_tree_resource.m_nodes.size(); i++) {
-      instance_node_descriptors[i] = AnimNodeDescriptorFactory(
+    instance_node_descriptors[i] = AnimNodeDescriptorFactory(
-          m_blend_tree_resource.m_nodes[i]->m_node_type_name,
+        m_blend_tree_resource.m_nodes[i]->m_node_type_name,
-          instance.m_nodes[i]);
+        instance.m_nodes[i]);
 
-    if (i > 1 && m_blend_tree_resource.m_nodes[i]->m_node_type_name == "BlendTree") {
+    if (i > 1
+        && m_blend_tree_resource.m_nodes[i]->m_node_type_name == "BlendTree") {
       instance_node_descriptors[i]->m_inputs =
           m_blend_tree_resource.m_nodes[i]->m_socket_accessor->m_inputs;
       instance_node_descriptors[i]->m_outputs =
@@ -611,6 +635,72 @@ void AnimGraphResource::PrepareBlendTreeIOData(
         connection.target_socket_name.c_str());
 
     AnimGraphConnection instance_connection;
+
+    if (source_node->m_node_type_name == "BlendTree") {
+      // For embedded subgraphs we have to ensure two things:
+      // 1. The parent graph target node must activate the source node within
+      //    the embedded subgraph.
+      // 2. The parent graph target node must activate the AnimNode of the
+      //    parent graph which contains the embedded subgraph. Otherwise, the
+      //    embedded graph does not get evaluated.
+      // For each case we have to add a connection here. First we insert the
+      // default connection within the graph (i.e. for case 2). Then we alter
+      // the source node such that it points to the node within the embedded
+      // subgraph.
+      AnimGraphConnection embedded_graph_activation_connection;
+      embedded_graph_activation_connection.m_source_node = source_node;
+      embedded_graph_activation_connection.m_source_socket = *source_socket;
+      embedded_graph_activation_connection.m_target_node = target_node;
+      embedded_graph_activation_connection.m_target_socket = *target_socket;
+      instance.m_node_input_connections[connection.target_node_index].push_back(
+          embedded_graph_activation_connection);
+      instance.m_node_output_connections[connection.source_node_index]
+          .push_back(embedded_graph_activation_connection);
+
+      AnimGraphResource* source_blend_tree_resource =
+          dynamic_cast<AnimGraphResource*>(
+              m_blend_tree_resource.m_nodes[connection.source_node_index]);
+      AnimGraphBlendTree* source_blend_tree =
+          dynamic_cast<AnimGraphBlendTree*>(source_node);
+
+      size_t source_blend_tree_output_node_index =
+          source_blend_tree_resource->m_blend_tree_resource
+              .GetNodeIndexForOutputSocket(connection.source_socket_name);
+      source_node =
+          source_blend_tree->m_nodes[source_blend_tree_output_node_index];
+      instance_connection.m_crosses_hierarchy = true;
+    } else if (target_node->m_node_type_name == "BlendTree") {
+      // When a connection points to an embedded blend tree we have to ensure
+      // that the embedded node knows about its connection partner in the parent
+      // tree. This allows the embedded node to properly activate the node in
+      // the parent graph.
+      AnimGraphResource* target_blend_tree_resource =
+          dynamic_cast<AnimGraphResource*>(
+              m_blend_tree_resource.m_nodes[connection.target_node_index]);
+      AnimGraphBlendTree* target_blend_tree =
+          dynamic_cast<AnimGraphBlendTree*>(target_node);
+
+      size_t target_blend_tree_output_node_index =
+          target_blend_tree_resource->m_blend_tree_resource
+              .GetNodeIndexForInputSocket(connection.target_socket_name);
+      target_node =
+          target_blend_tree->m_nodes[target_blend_tree_output_node_index];
+
+      // Make sure that the embedded node input activates the parent graph node.
+      std::vector<AnimGraphConnection>& embeded_target_node_inputs =
+          target_blend_tree
+              ->m_node_input_connections[target_blend_tree_output_node_index];
+      for (size_t j = 0; j < embeded_target_node_inputs.size(); j++) {
+        AnimGraphConnection& embedded_target_connection =
+            embeded_target_node_inputs[j];
+        if (embedded_target_connection.m_source_socket.m_name
+            == target_socket->m_name) {
+          embedded_target_connection.m_source_node = source_node;
+          embedded_target_connection.m_crosses_hierarchy = true;
+        }
+      }
+    }
+
     instance_connection.m_source_node = source_node;
     instance_connection.m_source_socket = *source_socket;
     instance_connection.m_target_node = target_node;
@@ -685,8 +775,9 @@ void AnimGraphResource::SetRuntimeNodeProperties(
   for (int i = 2; i < m_blend_tree_resource.m_nodes.size(); i++) {
     const AnimNodeResource* node_resource = m_blend_tree_resource.m_nodes[i];
 
-    NodeDescriptorBase* node_instance_accessor =
+    NodeDescriptorBase* node_instance_accessor = AnimNodeDescriptorFactory(
-        AnimNodeDescriptorFactory(node_resource->m_node_type_name, result.m_nodes[i]);
+        node_resource->m_node_type_name,
+        result.m_nodes[i]);
 
     std::vector<Socket>& resource_properties =
         node_resource->m_socket_accessor->m_properties;
@@ -741,7 +832,8 @@ bool AnimGraphResource::SaveStateMachineResourceToFile(
   return false;
 }
 
-bool AnimGraphResource::LoadStateMachineResourceFromJson(nlohmann::json const& json_data) {
+bool AnimGraphResource::LoadStateMachineResourceFromJson(
+    nlohmann::json const& json_data) {
   assert(false && "Not yet implemented");
 
   return false;

src/AnimGraph/AnimGraphResource.h

@@ -100,6 +100,32 @@ struct BlendTreeResource {
 
     return result;
   }
+
+  size_t GetNodeIndexForOutputSocket(const std::string& socket_name) const {
+    for (size_t i = 0; i < m_connections.size(); i++) {
+      const BlendTreeConnectionResource& connection = m_connections[i];
+      if (connection.target_node_index == 0 && connection.target_socket_name == socket_name) {
+        return connection.source_node_index;
+      }
+    }
+
+    std::cerr << "Error: could not find a node connected to output '" << socket_name << "'." << std::endl;
+
+    return -1;
+  }
+
+  size_t GetNodeIndexForInputSocket(const std::string& socket_name) const {
+    for (size_t i = 0; i < m_connections.size(); i++) {
+      const BlendTreeConnectionResource& connection = m_connections[i];
+      if (connection.source_node_index == 1 && connection.source_socket_name == socket_name) {
+        return connection.target_node_index;
+      }
+    }
+
+    std::cerr << "Error: could not find a node connected to input '" << socket_name << "'." << std::endl;
+
+    return -1;
+  }
 };
 
 struct StateMachineTransitionResources {
@@ -131,6 +157,7 @@ struct AnimGraphResource: AnimNodeResource {
   bool SaveBlendTreeResourceToFile(const char* filename) const;
   void CreateBlendTreeRuntimeNodeInstances(AnimGraphBlendTree& result) const;
   void PrepareBlendTreeIOData(AnimGraphBlendTree& instance) const;
+  void CreateBlendTreeConnectionInstances(AnimGraphBlendTree& instance) const;
   void SetRuntimeNodeProperties(AnimGraphBlendTree& result) const;
 
   bool SaveStateMachineResourceToFile(const char* filename) const;

src/AnimGraph/AnimGraphStateMachine.cc

@@ -8,11 +8,11 @@ bool AnimGraphStateMachine::Init(AnimGraphContext& context) {
   
 }
 
-void AnimGraphStateMachine::MarkActiveInputs() {
+void AnimGraphStateMachine::MarkActiveInputs(const std::vector<AnimGraphConnection>& input_connections) {
   
 }
 
-void AnimGraphStateMachine::CalcSyncTrack() {
+void AnimGraphStateMachine::CalcSyncTrack(const std::vector<AnimGraphConnection>& input_connections) {
   
 }
 

src/AnimGraph/AnimGraphStateMachine.h

@@ -25,8 +25,8 @@ struct AnimGraphStateMachine : public AnimNode {
   Transition* m_active_transition = nullptr;
 
   bool Init(AnimGraphContext& context);
-  void MarkActiveInputs() override;
+  void MarkActiveInputs(const std::vector<AnimGraphConnection>& input_connections) override;
-  void CalcSyncTrack() override;
+  void CalcSyncTrack(const std::vector<AnimGraphConnection>& input_connections) override;
   void UpdateTime(float time_last, float time_now) override;
   void Evaluate(AnimGraphContext& context) override;
 };

src/AnimGraph/AnimNode.h

@@ -8,8 +8,8 @@
 #include <string>
 #include <vector>
 
-#include "SyncTrack.h"
 #include "AnimGraphData.h"
+#include "SyncTrack.h"
 
 struct AnimNode;
 
@@ -25,29 +25,35 @@ enum class AnimNodeEvalState {
 struct AnimNode {
   std::string m_name;
   std::string m_node_type_name;
+  int m_tick_number = 0;
   AnimNodeEvalState m_state = AnimNodeEvalState::Undefined;
 
   float m_time_now = 0.f;
   float m_time_last = 0.f;
   SyncTrack m_sync_track;
 
-  std::vector<AnimGraphConnection> m_inputs;
-
   virtual ~AnimNode() = default;
 
-  virtual bool Init(AnimGraphContext& context) { return true; };
+  virtual bool Init(AnimGraphContext& context) {
+    m_time_now = 0.f;
+    m_time_last = 0.f;
+    return true;
+  };
 
-  virtual void MarkActiveInputs() {
+  virtual void MarkActiveInputs(
-    for (const auto & input : m_inputs) {
+      const std::vector<AnimGraphConnection>& input_connections) {
+    for (const auto& input : input_connections) {
       AnimNode* input_node = input.m_source_node;
       if (input_node != nullptr) {
+        input_node->m_tick_number = m_tick_number;
         input_node->m_state = AnimNodeEvalState::Activated;
       }
     }
   }
 
-  virtual void CalcSyncTrack() {
+  virtual void CalcSyncTrack(
-    for (const auto & input : m_inputs) {
+      const std::vector<AnimGraphConnection>& input_connections) {
+    for (const auto& input : input_connections) {
       AnimNode* input_node = input.m_source_node;
       if (input_node != nullptr
           && input.m_source_socket.m_type == SocketType::SocketTypeAnimation

tests/AnimGraphResourceTests.cc

@@ -140,7 +140,9 @@ class EmbeddedBlendTreeGraphResource {
   BlendTreeResource* embedded_blend_tree_resource = nullptr;
 
   size_t walk_node_index = -1;
-  AnimNodeResource* walk_node = nullptr;
+  AnimNodeResource* walk_node_resource = nullptr;
+  size_t embedded_blend_tree_node_index = -1;
+  size_t embedded_speed_scale_index = -1;
 
  public:
   EmbeddedBlendTreeGraphResource() {
@@ -163,10 +165,11 @@ class EmbeddedBlendTreeGraphResource {
     // Parent AnimSampler
     parent_blend_tree_resource->m_nodes.push_back(
         AnimNodeResourceFactory("AnimSampler"));
+    walk_node_index = parent_blend_tree_resource->m_nodes.size() - 1;
 
-    walk_node = parent_blend_tree_resource->m_nodes.back();
+    walk_node_resource = parent_blend_tree_resource->m_nodes[walk_node_index];
-    walk_node->m_name = "WalkAnim";
+    walk_node_resource->m_name = "WalkAnim";
-    walk_node->m_socket_accessor->SetPropertyValue(
+    walk_node_resource->m_socket_accessor->SetPropertyValue(
         "Filename",
         std::string("media/Walking-loop.ozz"));
 
@@ -175,7 +178,7 @@ class EmbeddedBlendTreeGraphResource {
     //
     parent_blend_tree_resource->m_nodes.push_back(
         AnimNodeResourceFactory("BlendTree"));
-    size_t embedded_blend_tree_node_index =
+    embedded_blend_tree_node_index =
         parent_blend_tree_resource->m_nodes.size() - 1;
     embedded_graph = dynamic_cast<AnimGraphResource*>(
         parent_blend_tree_resource->m_nodes.back());
@@ -201,9 +204,13 @@ class EmbeddedBlendTreeGraphResource {
     // Embedded: SpeedScale node
     embedded_blend_tree_resource->m_nodes.push_back(
         AnimNodeResourceFactory("SpeedScale"));
+    embedded_speed_scale_index =
+        embedded_blend_tree_resource->m_nodes.size() - 1;
     AnimNodeResource* embedded_speed_scale_resource =
-        embedded_blend_tree_resource->m_nodes.back();
+        embedded_blend_tree_resource->m_nodes[embedded_speed_scale_index];
-    embedded_speed_scale_resource->m_socket_accessor->SetInputValue("SpeedScale", 0.1f);
+    embedded_speed_scale_resource->m_socket_accessor->SetInputValue(
+        "SpeedScale",
+        0.1f);
 
     // Embedded: setup connections
     embedded_blend_tree_resource->ConnectSockets(
@@ -219,7 +226,7 @@ class EmbeddedBlendTreeGraphResource {
 
     // Parent: setup connections
     REQUIRE(parent_blend_tree_resource->ConnectSockets(
-        walk_node,
+        walk_node_resource,
         "Output",
         embedded_graph,
         "AnimInput"));
@@ -346,8 +353,8 @@ TEST_CASE_METHOD(
   AnimSamplerNode* anim_sampler_walk =
       dynamic_cast<AnimSamplerNode*>(anim_graph_blend_tree.m_nodes[2]);
 
-  BlendTreeNode* graph_output_node =
+  BlendTreeSocketNode* graph_output_node =
-      dynamic_cast<BlendTreeNode*>(anim_graph_blend_tree.m_nodes[0]);
+      dynamic_cast<BlendTreeSocketNode*>(anim_graph_blend_tree.m_nodes[0]);
 
   // check node input dependencies
   size_t anim_sampler_index =
@@ -937,7 +944,8 @@ TEST_CASE_METHOD(
       parent_blend_tree_resource->m_nodes.size()
       == parent_blend_tree_resource_loaded.m_nodes.size());
   for (size_t i = 0; i < parent_blend_tree_resource->m_nodes.size(); i++) {
-    const AnimNodeResource* parent_node = parent_blend_tree_resource->m_nodes[i];
+    const AnimNodeResource* parent_node =
+        parent_blend_tree_resource->m_nodes[i];
     const AnimNodeResource* parent_node_loaded =
         parent_blend_tree_resource_loaded.m_nodes[i];
 
@@ -949,7 +957,8 @@ TEST_CASE_METHOD(
   CHECK(
       parent_blend_tree_resource->m_connections.size()
       == parent_blend_tree_resource_loaded.m_connections.size());
-  for (size_t i = 0; i < parent_blend_tree_resource->m_connections.size(); i++) {
+  for (size_t i = 0; i < parent_blend_tree_resource->m_connections.size();
+       i++) {
     const BlendTreeConnectionResource& parent_connection =
         parent_blend_tree_resource->m_connections[i];
     const BlendTreeConnectionResource& parent_connection_loaded =
@@ -1039,22 +1048,61 @@ TEST_CASE_METHOD(
   graph_context.m_skeleton = &skeleton;
 
   blend_tree.Init(graph_context);
-  // Marking of active inputs is not properly working as we do not properly
+
-  // populate AnimNode::m_inputs.
+  const AnimSamplerNode* walk_node =
-  //
+      dynamic_cast<AnimSamplerNode*>(blend_tree.m_nodes[walk_node_index]);
-  // Here comes an iffy problem: How to mark nodes in a parent blend tree
+  const AnimGraphBlendTree* embedded_blend_tree_node =
-  //   as active?
+      dynamic_cast<AnimGraphBlendTree*>(
-  //
+          blend_tree.m_nodes[embedded_blend_tree_node_index]);
-  // - Simplest would be if the AnimNodes don't distinguish between nodes within
+  const SpeedScaleNode* speed_scale_node = dynamic_cast<SpeedScaleNode*>(
-  //   the tree they are contained or in a possible parent (or nested) tree.
+      embedded_blend_tree_node->m_nodes[walk_node_index]);
-  // - But then how to propagate active connections across multiple layers?
+
-  // - Therefore probably better to have a blend tree store which sockets are
+  blend_tree.StartUpdateTick();
-  //   active and use that within the graph.
+  blend_tree.MarkActiveInputs(std::vector<AnimGraphConnection>());
-  // - But then: AnimGraphConnection already stores raw AnimNode pointers of the
+  REQUIRE(embedded_blend_tree_node->m_state == AnimNodeEvalState::Activated);
-  //   connected nodes. Still... populating them accross layers could be messy.
+  REQUIRE(speed_scale_node->m_state == AnimNodeEvalState::Activated);
-  blend_tree.MarkActiveInputs();
+  REQUIRE(walk_node->m_state == AnimNodeEvalState::Activated);
-  blend_tree.UpdateTime(0.f, 0.1f);
+
+  float time_last = 0.f;
+  float dt = 0.1f;
+  blend_tree.UpdateTime(time_last, time_last + dt);
+  CHECK(embedded_blend_tree_node->m_state == AnimNodeEvalState::TimeUpdated);
+  CHECK(speed_scale_node->m_state == AnimNodeEvalState::TimeUpdated);
+  CHECK(walk_node->m_state == AnimNodeEvalState::TimeUpdated);
+
+  CHECK_THAT(
+      walk_node->m_time_last,
+      Catch::Matchers::WithinAbs(time_last, 0.001));
+  CHECK_THAT(
+      walk_node->m_time_now,
+      Catch::Matchers::WithinAbs(
+          time_last + dt * (*speed_scale_node->i_speed_scale),
+          0.001));
+
   blend_tree.Evaluate(graph_context);
 
+  WHEN("Updating the time a second time") {
+    // Perform another update
+    time_last = time_last + dt;
+    dt = 0.3f;
+    blend_tree.StartUpdateTick();
+    blend_tree.MarkActiveInputs(std::vector<AnimGraphConnection>());
+    blend_tree.UpdateTime(time_last, time_last + dt);
+    CHECK(embedded_blend_tree_node->m_state == AnimNodeEvalState::TimeUpdated);
+    CHECK(speed_scale_node->m_state == AnimNodeEvalState::TimeUpdated);
+    CHECK(walk_node->m_state == AnimNodeEvalState::TimeUpdated);
+
+    CHECK_THAT(
+        walk_node->m_time_last,
+        Catch::Matchers::WithinAbs(
+            time_last * (*speed_scale_node->i_speed_scale),
+            0.001));
+    CHECK_THAT(
+        walk_node->m_time_now,
+        Catch::Matchers::WithinAbs(
+            (time_last + dt) * (*speed_scale_node->i_speed_scale),
+            0.001));
+  }
+
   graph_context.freeAnimations();
 }