Move MatrixTransform up to IEntityNode interface

Avoid a new dynamic_cast in EntityNode's attachment handling by migrating the
MatrixTransform interface up to IEntityNode, so that localToParent() is
accessible as soon as the IEntityNodePtr has been created by the entity module.

include/ientity.h

@@ -6,6 +6,7 @@
 #include "irender.h"
 #include "inameobserver.h"
 #include "iscenegraph.h"
+#include "itransformnode.h"
 #include <functional>
 
 #include "string/predicate.h"
@@ -263,11 +264,17 @@ class Entity
     virtual void forEachAttachment(AttachmentFunc func) const = 0;
 };
 
-/// Interface for a INode subclass that contains an Entity
-class IEntityNode :
-    public IRenderEntity,
-    public virtual scene::INode,
-    public scene::Cloneable
+/**
+ * \brief Interface for a node which represents an entity.
+ *
+ * As well as providing access to the entity data with getEntity(), every
+ * IEntityNode can clone itself and apply a transformation matrix to its
+ * children (which might be brushes, patches or other entities).
+ */
+class IEntityNode : public IRenderEntity,
+                    public virtual scene::INode,
+                    public scene::Cloneable,
+                    public IMatrixTransform
 {
 public:
     virtual ~IEntityNode() {}

include/itransformnode.h

@@ -4,18 +4,27 @@
 
 class Matrix4;
 
-/// \brief A transform node.
+/// A node which can transform the coordinate space of its children
 class ITransformNode
 {
 public:
     virtual ~ITransformNode() {}
 
 	/// \brief Returns the transform which maps the node's local-space into the local-space of its parent node.
-	virtual const Matrix4& localToParent() const  = 0;
+	virtual const Matrix4& localToParent() const = 0;
 };
 typedef std::shared_ptr<ITransformNode> ITransformNodePtr;
 
 inline ITransformNodePtr Node_getTransformNode(const scene::INodePtr& node)
 {
 	return std::dynamic_pointer_cast<ITransformNode>(node);
 }
+
+/// An ITransformNode which can provide non-const access to its transform matrix
+class IMatrixTransform: public ITransformNode
+{
+public:
+
+    /// Return a modifiable reference to a contained transformation matrix
+	virtual Matrix4& localToParent() = 0;
+};

libs/transformlib.h

@@ -17,28 +17,6 @@ class IdentityTransform :
 	}
 };
 
-/// \brief A transform node which stores a generic transformation matrix.
-class MatrixTransform :
-	public ITransformNode
-{
-	Matrix4 _localToParent;
-public:
-	MatrixTransform() :
-		_localToParent(Matrix4::getIdentity())
-	{}
-
-	Matrix4& localToParent()
-	{
-		return _localToParent;
-	}
-
-	/// \brief Returns the stored local->parent transform.
-	const Matrix4& localToParent() const
-	{
-		return _localToParent;
-	}
-};
-
 namespace scene
 {
 

radiantcore/entity/EntityNode.cpp

@@ -32,9 +32,9 @@ EntityNode::EntityNode(const EntityNode& other) :
 	Namespaced(other),
 	TargetableNode(_spawnArgs, *this),
 	Transformable(other),
-	MatrixTransform(other),
 	_eclass(other._eclass),
 	_spawnArgs(other._spawnArgs),
+    _localToParent(other._localToParent),
 	_namespaceManager(_spawnArgs),
 	_nameKey(_spawnArgs),
 	_renderableName(_nameKey),
@@ -143,8 +143,7 @@ void EntityNode::createAttachedEntities()
 
             // Set the attached entity's transform matrix according to the
             // required offset
-            MatrixTransform& mt = dynamic_cast<MatrixTransform&>(*attachedEnt);
-            mt.localToParent() = Matrix4::getTranslation(a.offset);
+            attachedEnt->localToParent() = Matrix4::getTranslation(a.offset);
         }
     );
 }

radiantcore/entity/EntityNode.h

@@ -32,8 +32,7 @@ class EntityNode :
 	public SelectionTestable,
 	public Namespaced,
 	public TargetableNode,
-	public Transformable,
-	public MatrixTransform	// influences local2world of child nodes
+	public Transformable
 {
 protected:
 	// The entity class
@@ -42,6 +41,9 @@ class EntityNode :
 	// The actual entity (which contains the key/value pairs)
 	SpawnArgs _spawnArgs;
 
+    // Transformation applied to this node and its children
+    Matrix4 _localToParent = Matrix4::getIdentity();
+
 	// The class taking care of all the namespace-relevant stuff
 	NamespaceManager _namespaceManager;
 
@@ -106,6 +108,10 @@ class EntityNode :
 	virtual float getShaderParm(int parmNum) const override;
 	virtual const Vector3& getDirection() const override;
 
+    // IMatrixTransform implementation
+    const Matrix4& localToParent() const override { return _localToParent; }
+    Matrix4& localToParent() override { return _localToParent; }
+
 	// SelectionTestable implementation
 	virtual void testSelect(Selector& selector, SelectionTest& test) override;