Orange Box (engine branch)

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The Source 2007 engine branch, also known as The Orange Box engine branch, was released in Oct 10, 2007 with the release of The Orange Box (, , and ), succeeding the Source 2006 engine branch. It was maintained side-by-side with the Left 4 Dead engine branch until 2010, when it was obsoleted by the release of the Alien Swarm engine branch. Despite this, the Source 2013 and Source 2013 Multiplayer branches were released in 2013 as more direct upgrades for these games.

In May - June 2010, all Source 2006 and Source 2007 games for PC are respectively upgraded to Source 2009, which adds support for macOS.

The Orange Box builds on the original Half-Life 2 branch, requiring its content installed to work.

Versions

There are three Orange Box branches, referred to in the SDK Launcher as Source 2007, Source 2009, and Source Multiplayer. The 2009 and MP branches do not have a different feature set, but they are incompatible with 2007 due to various under-the-bonnet changes (which include a different SteamID scheme and Mac OS X compatibility).

Features

New since the Source 2006 engine branch are:

2007

Threading: Logic, rendering and audio have been threaded for performance gains in multi-core environments.
Soft particles: An all-new, artist-driven particle system, replacing the old hard-coded particle system.
Shadow mapping: Special dynamic lights such as the player's flashlight can now cast high-quality dynamic shadows.
Improved High Dynamic Range rendering: Remade HDR tonemapping that better fits outdoor scenes.[1]
Motion blur: Cheap and simple camera motion blur.[1]
Hardware Morph (HWM) flexes and Wrinkle maps: A new, powerful facial animation system, with support for textures that add fine wrinkling detail to the face during flex animation.
Conditional statements: New conditional statements for use in materials to optimize them for lower-end machines.
Phongwarp textures and other Phong improvements: Source's phong shading, introduced in Source 2006, has been upgraded with additional features such as reflection tinting, albedo tinting, phongwarp textures, and more.
Self-shadowing bump maps: A special, cheaper kind of bump map for brush shaders with baked in shadows to give the illusion of a self-shadowing surface.
Automatic displacement texturing: Mitigates texture stretching across displacement surfaces.
Alpha to coverage: Vector-like edges to raster images, fast.
Flowing emissive textures for models: Advanced flowing emission for VertexLitGeneric, notably used on the Vortigaunts in Half-Life 2: Episode Two.
Fresnel for specular reflections and self-illumination on models: On VertexLitGeneric, $envmap and $selfillum have new parameters to enable shading with the Fresnel effect.
Cinematic Physics: Baked physics animations that are rendered offline and brought into the engine for playback with minimal performance cost.
Visclusters: A new entity to be placed in large open areas with unbroken visiblity, reducing compile times.
Maplist Thumbnails: A console-oriented server browser UI.
Xbox 360 support: Of little use to modders, needless to say!

2009/MP

Mac OS X support: The engine can now run on Mac. However, Mac support outside of official games may be spotty. Furthermore, newer version of macOS since 10.15 (Catalina) no longer support 32-bit apps and games in general (including every single Source engine games that are complied for 32-bit only).
Particle system adjustments: Particles can now render blobs and models. Not ported back to Source 2013.
Disable phys_bone_followers: phys_bone_followers can now be disabled on dynamic props for performance gains and lower entity counts.

2013

Source 2013 (both SP and MP) has its own page.

Availability

Most games using this branch (except Console version of those games) were upgraded to the Source 2013 or Source 2013 Multiplayer branches when those released. Nevertheless, gamecode for the 2007 branch is included in the now-deprecated Source SDK app.