started node graph design

nodes/nodegraph.h

@@ -8,7 +8,46 @@ class NodeGraph
 public:
   NodeGraph();
 
-private:
+  /**
+   * @brief Add a node to this graph
+   *
+   * The graph takes ownership of the node.
+   *
+   * @param node
+   */
+  void AddNode(EffectPtr node);
+
+  /**
+   * @brief Process the graph
+   *
+   * Using the output node set by SetOutputNode(), this function will work backwards and perform every action in the
+   * node hierarchy necessary to eventually process the output node. After this function returns, the output node should
+   * contain valid values ready for accessing.
+   *
+   * Each node will cache its output for optimized playback and rendering. This will happen transparently and under most
+   * circumstances, this function will be able to return immediately.
+   */
+  void Process();
+
+  /**
+   * @brief Set the output node for this node graph
+   *
+   * This node will be presented as the final node that all other nodes converge on. This node can be used to retrieve
+   * the result of the graph.
+   *
+   * @param node
+   *
+   * The node to set as the output node. The graph takes ownership of the node and the user cannot delete it.
+   */
+  void SetOutputNode(EffectPtr node);
+
+  /**
+   * @brief Returns the currently set output node
+   */
+  Effect* OutputNode();
+
+private:  
+  EffectPtr output_node_;
 };
 
 #endif // NODEGRAPH_H