Are there any good game editor open source for level designer? [closed]

Question

I'm finding a good game editor open source (c/c++/objective-c) specially for level designer. At now, I know Tiled Map Editor but it only focus on tile map.
In brief, I need a tool that I can design many game levels on it (design by dragging game objects (actor, wall, ball, tree, etc) to screen editor, define properties (density, restitution, friction, etc) for each objects, etc) then exporting all them to xml file and my game code will read from this xml file to generate the interface.

Please comment if you don't understand my question clearly.

Many thank in advance for any advices on this.
Tien

Answer 1

I have been looking for something like this myself for some time now, and I think I just found our answer in another question:

Check out Nitro Level Editor - it's XML based and fit for virtually any 2D game or application. http://nle.nickmania.com/

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