According to The Inq, the water texture that was found in both S.T.A.L.K.E.R. and Half-Life 2 actually comes from a texture pack sold by Marlin Studios. Marlin lists both Valve as well as S.T.A.L.K.E.R. publisher THQ as "noteworthy users" of its textures along with companies like Electronic Arts, Konami, and Epic Games. The situation regarding light textures is a little less clear, but The Inq claims that some of its sources have discovered that S.T.A.L.K.E.R.'s lights_impflash texture that was allegedly stolen from Doom 3 is actually a generic impact flash texture—not a texture specific to the Doom 3's Imp monster. The site doesn't mention that texture's provenance, however.