Editing Source (game engine) (section)

==== Source 2006 ====
[[File:Half-Life 2 Episode One Citadel Base.jpg|thumb|upright=1.2|A screenshot of ''[[Half-Life 2: Episode One]]''. The [[high-dynamic-range rendering]] and [[Phong shading]] effects are evident.]]

The Source 2006 branch was the term used for Valve's games using technology that culminated with the release of ''Half-Life 2: Episode One''. [[High-dynamic-range rendering|HDR rendering]] and [[color correction]] were first implemented in 2005 using ''[[Day of Defeat: Source]]'', which required the engine's shaders to be rewritten.<ref name="hdr_shaders">{{cite video game |title=[[Half-Life 2: Lost Coast]] |developer=[[Valve Corporation|Valve]] |year=2005 |platform=PC |quote='''Chris Green''': The Source engine supports a wide variety of shaders. The refraction shader on the window here requires us to copy the scene to a texture, refract it, and then apply it the window surface. To fully support HDR, every shader in the engine needed to be updated, so this refraction shader was improved to the support the full range of contrast.}}</ref> The former, along with developer commentary tracks, were showcased in ''[[Half-Life 2: Lost Coast]]''.  ''Episode One'' introduced [[Phong shading]] and other smaller features. [[Image-based modeling and rendering|Image-based rendering]] technology had been in development for ''[[Half-Life 2]]'',<ref name="driverheaven-2003">{{cite web |url=http://www.driverheaven.net/dhinterviews/gabenewell/ |title=Interview with Gabe Newell |work=DriverHeaven.net |access-date=November 21, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20090628171827/http://www.driverheaven.net/dhinterviews/gabenewell/ |archive-date=June 28, 2009 }}</ref> but was cut from the engine before its release. It was mentioned again by [[Gabe Newell]] in 2006 as a piece of technology he would like to add to Source to implement support for much larger scenes that are impossible with strictly [[Polygon (computer graphics)|polygonal]] objects.<ref name="1up-valveweek">{{cite web |url=http://valve.1up.com/ |work=[[1UP.com]] |title=Valve Week |access-date=July 14, 2006 |url-status=dead |archive-url=https://web.archive.org/web/20060713230939/http://valve.1up.com/ |archive-date=July 13, 2006}}</ref>