public void setDepthFunc(TestFunction depthFunc) {       
        applyDepthFunc = true;
        this.depthFunc = depthFunc;
        cachedHashCode = -1;
    }
Set the depth comparison function to the given TestFunction
default is LessOrEqual (GL_LEQUAL)

@see TestFunction
@see RenderState#setDepthTest(boolean) 
@param depthFunc the depth comparison function
jme3-core/src/main/java/com/jme3/material/RenderState.java