I built from source and for me the Terrain sample crashes with: An exception has occured: OGRE EXCEPTION(5:ItemIdentityException): Compute Job with name Terra/ShadowGenerator not found in HlmsCompute::findComputeJob at /home/tarceri/merc/Ogre/OgreMain/src/OgreHlmsCompute.cpp (line 570) Tested with Mesa/LLVM master.