Portal 2: Desolation is giving the classic puzzle game a huge graphics overhaul

Portal 2: Desolation is a fan project that’s currently in development, a whole new singleplayer campaign in the Portal setting. It’s basically a community-made Portal 3, or at least Portal 2.5, being made “in tribute to Valve’s Iconic series”, as Emberspark Games puts it. The developers have spent the last year getting Desolation’s graphics to look slick, which has meant totally replacing the Source Engine’s rendering and lighting pipeline.

While Portal 2 already looked nice, its lighting was baked-in via a separate editor once levels were laid out, and the results could only be seen after maps were compiled. Any changes to light sources meant recompiling again, which is a time-consuming process—especially as maps get bigger and compile times expand. 

source: gamezpot.com