#5622: Implement fingerprinting of entity nodes (layer or grouping in…

…formation are disregarded)

radiantcore/entity/EntityNode.cpp

@@ -5,6 +5,8 @@
 #include "icounter.h"
 #include "imodel.h"
 #include "itransformable.h"
+#include "math/Hash.h"
+#include "string/case_conv.h"
 
 #include "EntitySettings.h"
 
@@ -202,6 +204,20 @@ const Vector3& EntityNode::getDirection() const
 	return _direction;
 }
 
+std::size_t EntityNode::getFingerprint()
+{
+    std::size_t hash = 0;
+
+    // Entities are just a collection of key/value pairs, use them lower case, ignore inherited keys
+    _spawnArgs.forEachKeyValue([&](const std::string& key, const std::string& value)
+    {
+        math::combineHash(hash, std::hash<std::string>()(string::to_lower_copy(key)));
+        math::combineHash(hash, std::hash<std::string>()(string::to_lower_copy(value)));
+    }, false);
+
+    return hash;
+}
+
 void EntityNode::testSelect(Selector& selector, SelectionTest& test)
 {
 	test.BeginMesh(localToWorld());

radiantcore/entity/EntityNode.h

@@ -3,6 +3,7 @@
 #include <sigc++/connection.h>
 #include "ientity.h"
 #include "inamespace.h"
+#include "icomparablenode.h"
 #include "Bounded.h"
 
 #include "scene/SelectableNode.h"
@@ -32,7 +33,8 @@ class EntityNode :
 	public SelectionTestable,
 	public Namespaced,
 	public TargetableNode,
-	public Transformable
+	public Transformable,
+    public scene::IComparableNode
 {
 protected:
 	// The entity class
@@ -113,6 +115,9 @@ class EntityNode :
     Matrix4 localToParent() const override { return _localToParent; }
     Matrix4& localToParent() override { return _localToParent; }
 
+    // IComparableNode implementation
+    std::size_t getFingerprint() override;
+
 	// SelectionTestable implementation
 	virtual void testSelect(Selector& selector, SelectionTest& test) override;