Source 2006
The 
Source 2006 engine branch, also known as the Episode One engine branch, and the last Old Engine branch, was first used in 2005 with 
Half-Life 2: Lost Coast and 
Day of Defeat: Source, but was not properly released until 2006 with 
Half-Life 2: Episode One, with previous multiplayer games (
, 
, and 
) also being upgraded to the Source 2006 branch then. It was distributed in "base source engine 2.gcf." It was obsoleted by Source 2007 (also known as Orange Box) branch. It requires Half-Life 2 content to operate.
The SDK and SDK Base game for this branch are free to all Steam users.
Todo: HDR actually predates Source 2006? see PowerPoint. Lost coast coast did not use "base source engine 2.gcf", and dods only used it after an update.
Features
New since 
Source 2004:
- High Dynamic Range rendering
- A simulation of brightness values outside computer monitors' actual range, and of aperture adjustment.
- Phong materials
- Diffuse reflections for skin and other roughened surfaces on models.
- Facial animation upgrades
- More detail and intenser shapes for close-up performances.
- Dynamic interactions
- Dynamic interactions between NPCs using special animations.
- Lightwarp textures
- 1D textures that tint a material per-texel depending on their brightness.
- DirectX 9 Shader Model 3 (
dxlevel 95) - Unlocks greatly improved shader performance.
- Detail prop shapes
- Improved detail sprites that sway in the breeze and bend away from nearby players.
Availability
Gamecode for the 2006 branch is included in the now-deprecated Source SDK app. Most Valve games introduced with Source 2006 and previous titles that are upgraded from Source 2004 to Source 2006 are now currently using Source 2013 Singleplayer or Source 2013 Multiplayer.
Usage
The following games still run on Source 2006:
Valve
2006 Source SDK Base 2006
Third-Party
2006
The Ship: Murder Party and The Ship: Single Player2006
Dark Messiah of Might and Magic2007
Eternal Silence2007
Fortress Forever2007
INSURGENCY: Modern Infantry Combat2007Iron Grip: The Oppression[confirm]2009
NEOTOKYO°
