View source for Source 2006

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The {{src06|4}} engine branch, also known as the '''Episode One''' engine branch, and the last '''Old Engine''' branch, was first released in 2005 with {{hl2lc|3.1}} and {{dods|3.1}}{{cn|Source 2006 introduced HDR, which was a major selling point of Lost Coast and DoD:S}} as a tech demo for [[HDR]] (High Dynamic Range rendering) and other graphical improvements, then later it was fully released in 2006 with {{hl2ep1|4}} and {{hldms|4}}, with previous games ({{css}}, {{hl2}}, and {{hls}}) also upgraded to the {{src06|3.1}} engine. It was obsoleted by the {{src07|3.1}} (also known as Orange Box) branch. It requires {{hl2|3.1}} content to operate.


The [[Source SDK|SDK]] and [[SDK Base]] game for this branch are free to all Steam users.

== Features ==

New since {{src04|4}}:

; [[High Dynamic Range|High Dynamic Range rendering]]
: A simulation of brightness values outside computer monitors' actual range, and of [[wikipedia:Aperture|aperture]] adjustment.
; [[Phong|Phong shading]]
: Diffuse reflections for skin and other roughened surfaces.
; [[Choreography creation|Facial animation upgrades]]
: More detail and intenser shapes for close-up performances.
; [[Dynamic interactions]]
: Dynamic interactions between NPCs using special animations.
; [[$lightwarptexture|Lightwarp textures]]
: 1D textures that tint a material per-texel depending on their brightness.
; [[mat_dxlevel|DirectX 9 Shader Model 3]] ({{code|style=2|dxlevel 95}})
: Unlocks greatly improved shader performance.
; [[Detail Props#Shapes|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 {{src06|3.1}} and previous titles that are upgraded from {{src04|3.1}} to {{src06|3.1}} are now currently using {{src13sp|3.1}} or {{src13mp|3.1}}.

* {{Code|style=2|2006}} {{Srcsdk06|4}}
* {{Code|style=2|2006}} {{ship|4}}
* {{Code|style=2|2006}} {{dmmm|4}}
* {{Code|style=2|2007}} {{esilence|4}}
* {{Code|style=2|2007}} {{ff|4}}
* {{Code|style=2|2007}} {{InsurgencyMIC}}
* {{Code|style=2|2007}} [[Iron Grip: The Oppression]]{{confirm}}
* {{Code|style=2|2009}} {{NT|4.1}}