This test uses 'PBRTerrain.j3md' to create a terrain Material for PBR.
 Upon running the app, the user should see a mountainous, terrain-based
 landscape with some grassy areas, some snowy areas, and some tiled roads and
 gravel paths weaving between the valleys. Snow should be slightly
 shiny/reflective, and marble texture should be even shinier. If you would
 like to know what each texture is supposed to look like, you can find the
 textures used for this test case located in jme3-testdata. (Screenshots
 showing how this test-case should look will also be available soon so you can
 compare your results, and I will replace this comment with a link to their
 location as soon as they are posted.)
 Press 'p' to toggle tri-planar mode. Enabling tri-planar mode should prevent
 stretching of textures in steep areas of the terrain.
 Press 'n' to toggle between night and day. Pressing 'n' will cause the light
 to gradually fade darker/brighter until the min/max lighting levels are
 reached. At night the scene should be noticeably darker.
 Uses assets from CC0Textures.com, licensed under CC0 1.0 Universal. For more
 information on the textures this test case uses, view the license.txt file
 located in the jme3-testdata directory where these textures are located:
 jme3-testdata/src/main/resources/Textures/Terrain/PBR
 
 Notes: (as of 12 April 2021)
 
 - 
 This shader is subject to the GLSL max limit of 16 textures, and users should
 consider using "AdvancedPBRTerrain.j3md" instead if they need additional
 texture slots.