Nodes: Log warnings instead of throwing on redefinitions of Node types (#27357)

This is the same behaviour as three.js itself has when it's imported multiple times.

examples/jsm/nodes/core/Node.js

@@ -458,7 +458,12 @@ export default Node;
 export function addNodeClass( type, nodeClass ) {
 
 	if ( typeof nodeClass !== 'function' || ! type ) throw new Error( `Node class ${ type } is not a class` );
-	if ( NodeClasses.has( type ) ) throw new Error( `Redefinition of node class ${ type }` );
+	if ( NodeClasses.has( type ) ) {
+
+		console.warn( `Redefinition of node class ${ type }` );
+		return;
+
+	}
 
 	NodeClasses.set( type, nodeClass );
 	nodeClass.type = type;

examples/jsm/nodes/lighting/LightsNode.js

@@ -173,7 +173,13 @@ export const lightNodes = nodeProxy( LightsNode );
 
 export function addLightNode( lightClass, lightNodeClass ) {
 
-	if ( LightNodes.has( lightClass ) ) throw new Error( `Redefinition of light node ${ lightNodeClass.type }` );
+	if ( LightNodes.has( lightClass ) ) {
+
+		console.warn( `Redefinition of light node ${ lightNodeClass.type }` );
+		return;
+
+	}
+
 	if ( typeof lightClass !== 'function' ) throw new Error( `Light ${ lightClass.name } is not a class` );
 	if ( typeof lightNodeClass !== 'function' || ! lightNodeClass.type ) throw new Error( `Light node ${ lightNodeClass.type } is not a class` );
 

examples/jsm/nodes/materials/NodeMaterial.js

@@ -541,7 +541,12 @@ export default NodeMaterial;
 export function addNodeMaterial( type, nodeMaterial ) {
 
 	if ( typeof nodeMaterial !== 'function' || ! type ) throw new Error( `Node material ${ type } is not a class` );
-	if ( NodeMaterials.has( type ) ) throw new Error( `Redefinition of node material ${ type }` );
+	if ( NodeMaterials.has( type ) ) {
+
+		console.warn( `Redefinition of node material ${ type }` );
+		return;
+
+	}
 
 	NodeMaterials.set( type, nodeMaterial );
 	nodeMaterial.type = type;

examples/jsm/nodes/shadernode/ShaderNode.js

@@ -15,7 +15,13 @@ const NodeElements = new Map(); // @TODO: Currently only a few nodes are added,
 
 export function addNodeElement( name, nodeElement ) {
 
-	if ( NodeElements.has( name ) ) throw new Error( `Redefinition of node element ${ name }` );
+	if ( NodeElements.has( name ) ) {
+
+		console.warn( `Redefinition of node element ${ name }` );
+		return;
+
+	}
+
 	if ( typeof nodeElement !== 'function' ) throw new Error( `Node element ${ name } is not a function` );
 
 	NodeElements.set( name, nodeElement );