[Portal 2]: postprocess_controller has a flawed implementation #464
Description
In all games post-Left 4 Dead 1, the entity postprocess_controller was added. Portal 2 is the only one of these games that does not implement such entity properly on it's engine branch, leading to only one effect functioning, that being vignette. Other iconic effects, such as film grain, local contrast, and depth and full screen blur (added to the entity in Alien Swarm) do not have any effect on the game.