Source engine

The Source Engine is a 3D game engine developed by Valve Corporation. Its unique features include a large degree of modularity and flexibility, an artist-driven, shader-based renderer, accurate lip sync and facial expression technology, and a powerful, efficient and completely network-enabled physics system. 

The Source engine was first shown to the world by being the power-horse behind the hugely anticipated Half-Life 2 which was released in late 2004. Since then the Source Engine has been upgraded with the release of such titles as Half-Life 2: Lost Coast, Team Fortress 2 and the Left 4 Dead series to name a few.

Whilst it has been years since the release of the Source Engine they haven't yet unveiled a 'next-generation engine' as the Source engine is always updating and is just as relevant in the gaming world today if not more than when it debuted in 2004. It has been aided by the release of the free Source Development Kit (SDK) which include such features as HDR for developers to use in their projects. Hence the reasons stated we have yet to see 'Source Engine 2'.

On July 10th 2012, Valve released the 'Source Filmmaker' - a freeware client to allowed anyone to make movies inside the Source Engine. More information on the Source Filmmaker can be found here.

Below you can find a list of amazing features that the Source Engine boasts:

Renderer

• Version 2.0 (and below) shaders, bump mapping, LOD on models and world
• Author shaders with HLSL
• Cube and environment mapping
• Dynamic lights, vertex lighting and light maps, many light types including flickering, pulsing etc.
• High-Dynamic Range lighting
• Water with refraction and fresnel effects
• Advanced particle system that can emit sprites or models
• Projected shadows allow for a large number of characters per scene
• Occluder entities for visibility blocking
• Indoor/Outdoor environments
• Deformable terrain
• 3D skyboxes extend the horizon and add parallax on distant objects
• Dynamically rendered organics (grass, trees etc)
• Subdivision surfaces, diffuse & specular bump maps
• Real-time radiosity lighting
• Effects include but are not limited to: particles, beams, volumetric smoke, sparks, blood, environmental effects like fog and rain
• Scalability
• Dx6-Dx9 hardware supported

Materials System

• Instead of traditional textures, Source defines sets of materials that specify what the object is made from and the texture used for that object. A material specifies how an object will fracture when broken, what it will sound like when broken or dragged across another surface, and what that object’s mass and buoyancy are. This system is much more flexible than other texture only based systems.
• Materials can interact with objects or NPCs such as mud or ice for vehicles to slide/lose traction on.

Multiplayer Network Code

• Time and gamer tested by millions of gamers around the world
• Support for both LAN based multiplayer and Internet based multiplayer games
• Prediction analysis for interpolating collision/hit detection
• Optimizations for high-latency, high-packet loss 56k connections

Advanced Characters

• Detailed and believable characters
• Realistic eyes
• Focus on player/object, not simply parallel views
• Proper eye “bulge” for realistic eye reflections
• Simulated musculature provides outstanding emotions, speech and body language
• Language independent speech, characters can naturally speak in many languages
• Skeletal/bone system for animation
• Layered animation system can synthesize complex animations out of several pieces