anchor.diff:  
   When you deal with complex game engine features like animations or physics it is handy to get feedback from the engine how it interpreted the current state. Is the physical object's collision shape really where you think it is? Is the skeleton of the animated character moving like you think it should? This document shows you how to activate visual debug aides.
   
  -What if you just want to quickly write code that loads models and brings them in their start position? You may not want to hunt for a sample model, convert it, add lights, and load materials. Instead you use “hasslefree simple shapes, and a “hasslefree unshaded material or wireframe: No model, no light source, no materials are needed to see them in your test scene.
  +What if you just want to quickly write code that loads models and brings them in their start position? You may not want to hunt for a sample model, convert it, add lights, and load materials. Instead you use "`hasslefree`" simple shapes, and a "`hasslefree`" unshaded material or wireframe: No model, no light source, no materials are needed to see them in your test scene.
   
   If you ever have problems with objects appearing in the wrong spot, with the wrong scale, or wrong orientation, simply attach debug shapes to your scene to have a point of reference in 3D space – just like a giant ruler. If your code positions the debug shapes correctly, but models remain invisible when you apply the same code to them, you know that the problem must be either the model (where is its origin coordinate?), or the light (too dark? too bright? missing?), or the model's material (missing?) – and not the positioning code.
   
  
positive.code:         wireMaterial.getAdditionalRenderState().setWireframe(true);
      }
  
      public void initialize(RenderManager rm, ViewPort vp) {
          renderManager = rm;
      }
  
      public void reshape(ViewPort vp, int w, int h) {
          throw new UnsupportedOperationException("Not supported yet.");
      }
  
      public boolean isInitialized() {
          return renderManager != null;
      }
  
      public void preFrame(float tpf) {
      }
  
      public void postQueue(RenderQueue rq) {
          renderManager.setForcedMaterial(wireMaterial);
      }
  
      public void postFrame(FrameBuffer out) {
          renderManager.setForcedMaterial(null);
      }
  
      public void cleanup() {
          renderManager.setForcedMaterial(null);
      }
  
  }
  ----
  
  
negative.code: 
  Then you can add a switch to toggle the model's wireframe on and off, like this:
  
  .  Create a key input trigger that switches between the two materials: E.g. we toggle when the T key is pressed.
  +
  [source,java]
  ----
      inputManager.addMapping("toggle wireframe", new KeyTrigger(KeyInput.KEY_T));
      inputManager.addListener(actionListener, "toggle wireframe");
  ----
  
  .  Now add the toggle action to the action listener.
  +
  [source,java]
  ----
  
  private ActionListener actionListener = new ActionListener() {
      @Override
      public void onAction(String name, boolean pressed, float tpf) {
          // toggle wireframe
          if (name.equals("toggle wireframe") && !pressed) {
              wireframe = !wireframe; // toggle boolean
              mat.getAdditionalRenderState().setWireframe(wireframe);
          }
          // else ... other input tests.
      }
  };
  ----
  
  .  Alternatively, you could traverse over the whole scene and toggle for all Geometry objects in there if you don't want to create a new SceneProcessor.
  +
  [source,java]
  ----
  
  private ActionListener actionListener = new ActionListener() {
      boolean wireframe = false;
  
      @Override
      public void onAction(String name, boolean pressed, float tpf) {
          // toggle wireframe
          if (name.equals("toggle wireframe") && !pressed) {
              wireframe = !wireframe; // toggle boolean
              rootNode.depthFirstTraversal(new SceneGraphVisitor() {
                  @Override
                  public void visit(Spatial spatial) {
                      if (spatial instanceof Geometry) {
                          ((Geometry) spatial).getMaterial().getAdditionalRenderState().setWireframe(wireframe);
                      }
                  }
              });
          }
          // else ... other input tests.
      }
  };
  ----
  
  
  TIP: To set the line width of wireframe display, use mesh.setLineWidth(lineWidth). Default line width is 1.
  
  
  == Example: Toggle Wireframe on the scene
  
  To display the wireframe of the entire scene instead on one material at a time, first create the following Scene Processor.
  
  [source,java]
  ----
  