anchor.diff:  
   Write a Java class that extends link:https://github.com/jMonkeyEngine/jmonkeyengine/blob/master/jme3-core/src/main/java/com/jme3/app/SimpleApplication.java[com.jme3.app.SimpleApplication].
   
  -*Learn more:* <<jme3/beginner/hello_simpleapplication#,Hello SimpleApplication>>, link:https://github.com/jMonkeyEngine/jmonkeyengine/blob/master/jme3-examples/src/main/java/jme3test/app/TestAppStateLifeCycle.java[TestAppStateLifeCycle].
  +*Learn more:*
  +
  +* <<jme3/beginner/hello_simpleapplication#,Hello SimpleApplication>>
  +* link:https://github.com/jMonkeyEngine/jmonkeyengine/blob/master/jme3-examples/src/main/java/jme3test/app/TestAppStateLifeCycle.java[TestAppStateLifeCycle].
   
   
   === How do I change the background color?
  
positive.code: material.getAdditionalRenderState().setWireframe(true);
  ----
  
  *Learn more:* <<jme3/advanced/debugging#,Debugging>>.
  
  
  == I want to control the camera
  
  The default camera `cam` is an instance of the `Camera` class.
  
  *Learn more:* link:https://github.com/jMonkeyEngine/jmonkeyengine/blob/master/jme3-core/src/main/java/com/jme3/renderer/Camera.java[com.jme3.renderer.Camera]
  
  
  === How do I keep the camera from moving?
  
negative.code: Geometry submesh = (Geometry) model.getChild("door 12");
  ----
  
  *Learn more:*
  
  * <<jme3/advanced/spatial#,Spatial>>
  
  
  === How do I make procedural or custom shapes?
  
  You can programmatically create com.jme3.scene.Mesh'es.
  
  *Learn more:*
  
  * <<jme3/advanced/custom_meshes#,Custom Meshes>>
  
  
  == I want to change the surface of objects in the scene
  