2015-09-20 Some slides by Naty Hoffman GAME_GFX "Physically-Based Rendering for Games—Reflectance and Beyond" I3D 2005 http://renderwonk.com/publications/i3d2005-tutorial/ "Real-time Photorealistic Terrain Lighting" GDC 2001 http://renderwonk.com/publications/gdc-2001/