GLRenderer: don't set depth function twice

jme3-core/src/main/java/com/jme3/renderer/RenderContext.java

@@ -241,12 +241,12 @@ public class RenderContext {
     public IDList attribIndexList = new IDList();
     
     /**
-     * depth tets function
+     * depth test function
      */
-    public RenderState.TestFunction depthFunc = RenderState.TestFunction.LessOrEqual;
+    public RenderState.TestFunction depthFunc = RenderState.TestFunction.Less;
     
      /**
-     * alpha tets function
+     * alpha test function
      */
     public RenderState.TestFunction alphaFunc = RenderState.TestFunction.Greater;
 

jme3-core/src/main/java/com/jme3/renderer/opengl/GLRenderer.java

@@ -614,13 +614,12 @@ public class GLRenderer implements Renderer {
 
         if (state.isDepthTest() && !context.depthTestEnabled) {
             gl.glEnable(GL.GL_DEPTH_TEST);
-            gl.glDepthFunc(convertTestFunction(context.depthFunc));
             context.depthTestEnabled = true;
         } else if (!state.isDepthTest() && context.depthTestEnabled) {
             gl.glDisable(GL.GL_DEPTH_TEST);
             context.depthTestEnabled = false;
         }
-        if (state.getDepthFunc() != context.depthFunc) {
+        if (state.isDepthTest() && state.getDepthFunc() != context.depthFunc) {
             gl.glDepthFunc(convertTestFunction(state.getDepthFunc()));
             context.depthFunc = state.getDepthFunc();
         }