Check for removal of children in the traverse method

Description of the problem

Removing children while using the traverse function will result in an error. I propose a second check to make sure that l = children inside the loop, in case a node is removed. Original:

traverse: function ( callback ) {

			callback( this );

			var children = this.children;

			for ( var i = 0, l = children.length; i < l; i ++ ) {

				children[ i ].traverse( callback );

			}

		}

My proposal:

traverse: function ( callback ) {

			callback( this );

			var children = this.children;

			for ( var i = 0, l = children.length; i < l; i ++ ) {
                                if(l != children.length){
                                l=children.length;
                                i--;
                                }
				children[ i ].traverse( callback );

			}

		}

There might be a better way to do it, but that change got my code working.

• jsfiddle

Three.js version

• Dev
• r94
• …

Browser

• All of them
• Chrome
• Firefox
• Internet Explorer

OS

• All of them
• Windows
• macOS
• Linux
• Android
• iOS

Hardware Requirements (graphics card, VR Device, …)

[WestLangley]

In general, Object3D.traverse() assumes that the structure of the scene graph does not change.

This should be documented.

@looeee IMHO, that is not necessary. It is reasonable to expect users to understand the ramifications of modifying a graph while traversing it. Same with an array. Save yourself some work. 😃

@jkulanko If you need further help, please use the forum.

Closing, as this is a user error.

[jkulanko]

@aardgoose I’m going to have to look into that because that seems like it might be a very good solution to my problem, thanks!

@looeee That wouldn’t quite work for me, because of my unique situation. I am receiving an individual part asynchronously from a backserver which contains a mesh and a line. Each of the parts is a leaf node to a larger tree structure, and therefore needs to take into account the matrices of its parent (or many parents). So I want to keep each mesh and line segments together in a single object as that represents one leaf.