Started on the engine proper

core/engine_node.h

@@ -0,0 +1,23 @@
+#pragma once
+
+#include "common.h"
+
+//forward declare
+typedef struct _engineNode EngineNode;
+typedef struct _engine Engine;
+
+//the interface function
+typedef void (*EngineNodeFn)(EngineNode* self, Engine* engine);
+
+//the node object, which forms a tree
+typedef struct _engineNode {
+	//use Toy's memory model
+	void* children;
+	int capacity;
+	int count;
+
+	EngineNodeFn onInit;
+	EngineNodeFn onStep;
+	EngineNodeFn onFree;
+} EngineNode;
+