My Favorite Game Engine... The Source Engine!

For as long as I can recall in my gaming history, I never really took an interest into how game engines worked.  As a child, if I could throw a game into my computer and have it run at 20 Fps, I was a happy camper.  Since I grew with a sub-par PC at home, I found it difficult to run a variety of the higher end games that always looked so great on my friends gaming PC's.  I had lost all hope for running one of these graphically intense games, until in 2005 I picked up Half-Life 2 from a designer called Valve.  When I popped the game into my CD drive, I was stunned at the look of the game and how well it was running on my PC!  At this point, I wanted to know what was so special about this game that it could run so smoothly on my not so great system.  This hunt led me to an article on the at the time year old Source engine.  I instantly fell in love and began picking up any game I could find that was using this great technology.

As you may be able to guess, I still love the Source engine today, so I found it fitting that I should do a blog post on an Engine that I still use to this day.  During the upcoming blog post, I am going to be outlining a bit of the history behind the source engine, some features relating to its design and use, as well as what Valve has planned for this incredible technology in the future.

I still can not believe I could run this on my machine!

A HISTORY OF THE SOURCE ENGINE

So before I get into the technical aspects of the Source Engine and the incredible features contained within it, I thought that it would be fitting to give some background on the engine and its creation.  The first deployment of the source engine was in 2004 when it was released in tandem with Counter Strike Source.  Players were amazed at the optimization of the engine and how well the game performed, even on low to high end systems.  Released shortly after CSS was Half-Life 2, which featured even more realistic character models, animation, facial movements and ragdoll physics.   Valve was being praised for this new source engine, however it would not have been possible without the GoldSrc engine, which in itself is a very heavily modified version on the Quake Engine from years past.  This use of the GoldSrc engine can even been seen in code snippets from both Half-Life 2 and CSS.  Although Valve did give credit to the GoldSrc engine, initially referring to their engine as the GoldSrc and Source engine, it was in 2003 at an E3 conference where the engine name "Source" became the one officially used by the public and Valve employees.  Over the years, the designers and programmers at Valve have taken on the task of replacing the original GoldSrc engine code, with their own better optimized code for current consoles and PC hardware.  

Since the source engine is an ever changing staple of Valves company, they needed a way to constantly be updating these features for the players, to always improve on their gaming experiences.  To accomplish this task, Valve decided to use their already successful steam online digital distributer to constantly feed the players with new updates as well as fixes that may be required for certain games.  This has allowed the Source engine to constantly evolve, and even be used in current upcoming next generation game titles such as Titanfall set to be released in 2014.  Now that you know a nice chunk of the history behind the engine, lets get into more of the technical aspects and what this engine is capable of.

Not a bad looking Logo either!

THE MEAT AND POTATOES OF THE ENGINE!

Since the creation of the Source Engine back in 2004 many different technologies have been developed for implementation in the engine, as well as removed when they have become outdated.  What I am going to be discussing was what is currently present in the Source Engine, thanks to an information licensing sheet released about the engine.  To start, I thought I would touch on some of the assets included in the Source renderer.  These features include Direct 3D rendering on PC's, Xbox systems, thanks to the multiple CPU cores included in all of these systems.  HDR or High Dynamic Range rendering is also included, as well as 3D bump mapping on all models in the game.  For rendering the lighting in their games, the Source engine uses pre-computed radiosity lighting as well as dynamic shadow maps on character and object models.  My favorite part of the engine, the physics engine, was derived from the classic physics engine that has been in use for years.  This physics engine is network-enabled and very bandwidth efficient to not disrupt players.  Among these major technologies included, the source engine contains water flow effects, dynamic 3D wounds, cloth simulation, an advanced particle system as well as a whole host of other features that are exciting to discover.  

One of the key areas of the engine that I really wanted to focus in on was the animation of characters faces and actions, as well as the material system included.  To start though, I am going to outline some of the key ways that Valve created these life like characters that we all fell in love with.  Using the source engine, the designers were able create characters with believable character traits, as well as interactive and intelligent responses to character movements and actions.  The Source engine a realistic eye system included, which allows the NPCs to focus on either the character or different objects, not just parallel views, while also adding realistic eye bulge that is present in humans.  The simulated muscularity of the characters provides emotions in speech in body language, while the Faceposer included can also be used to craft more dramatic emotions and lip syncing.  Another animation asset included is the skeletal and bone system, as well as the layered animation system.  When used together, these two features can synthesize complex animations out of several pieces of data.  Now we come to the material system used in the source engine.  Valve really took everything into account when creating this system, since instead of traditional textures each object is given sets of materials to define what the object is made of and what texture to use.  These materials are important, as they define what the object will do when fractured, dragged along a surface, as well as its mass and buoyancy.  It is a very interactive system to use and can even have effects on NPCs or objects, such as mud slowing a character, or ice causing them to slide.  I was really intrigued by how this system works, and it shows through in the games how well it works.

Since we have discussed some of the background elements of the engine that the players know is there, but don't pay a second though too, lets discuss some of the features we interact with all the time.  These features of course are the multiplayer, AI, the sound, and the UI that is implemented in the games using the Source engine.  Since we are touching on the multiplayer first, I thought it would be fitting to discuss how robust the networking code of the Source engine is, as it allows support for up 32 players in both LAN and internet based play.  Not only this, but a complete toolset is included to for use by level designers, character animators, and the creation of demos for players to experiment with.  Since collision can sometimes run into some faults via multiplayer play, the source engine includes a prediction analysis system, that is used for interpolation collisions and hit detections of players and objects.  This makes for a much smoother online play experience for all players.  Having tested it myself many times, I can say that the multiplayer in the Source engine has worked flawlessly for me over many different games and consoles.  

The AI in the source engine is what truly helps to bring many of Valves cult classics to life.  This is evident in games such as the Half Life series, where the player is able to form strong meaningful bonds with characters such as Dr. Kleiner and Alyx Vance.  This is thanks to the advanced AI included in the Source engine that allows for these meaningful interactions.  This AI includes features like graphical entity placement for level designers to quickly control the game environment, sophisticated navigation to allow characters to run, jump, climb, and take cover.  The AI also use senses to see, hear, and smell, as well as determine whether an entity is friend foe or just an object.  The one feature of the AI that truly stuck out to me however, was the squad AI.  Upon finding survivors, they will join your party and behave like a real military unit.  The characters operate together, knowing when to advance, take cover, suppress the enemy and retreat to different cover.  It was a really immersive feature included in the source engine and helped to further the realism of the game. 

The Source engine is fully supportive of 5.1 surround for up to 4 speakers.  A high quality 3D spatialization effect is also included to give the character a sense of distance and direction of the enemies.   The engine also has a pre-authorized doppler effect included, as well as support for users to stream audio on any wave.  The audio really helps to bring to life the fights, especially when alien weaponry is involved in games such as Half-Life 2!

Finally we come to the user interface of the source engine.  The source engine uses a very simplistic approach when it comes to their UI, however it successfully gets the job done.  The main area where the UI's simplistic nature works well is in the multiplayer server browsing area.  The server browser displays all of the currently active servers for the player to choose from, as well information pertaining to each.  From this screen the player is able to filter out different settings, pick favourites, and see past servers to help with their choice.  The messenger in the source engine can also be used here for chatting with friends, as well as joining servers that friends are currently playing in.  Its a great interface and although I struggled with it at first, I now know why the Source engine includes this UI in all of their games.

WHERE IS THE SOURCE ENGINE HEADED

Now as I have previously mentioned, the source engine is constantly being updated with new content to help further the gamers experience, however there are a few different technologies Valve is working on to improve Source.  The first of these is the development of new content authoring toolsets.  Since Valve has received a heavy amount of criticism over their Source SDK toolset, in regards to being outdated and too difficult to use, Valve has invested many of their assets into creating these new sets.  The new toolsets will allow content to be created faster and more efficiently as even Gave Newell himself has called the curent tools "sluggish and very painful to use"

There have also been confirmation as to Valve creating a brand new engine which they have named the "Source 2 Engine".  The engine has been in development for some time now and currently Valve is waiting for an appropriate title to launch the engine with, similar to how they launched Source with the Counter Strike Source title.  

The final piece of technology that Valve has been attempting to integrate into their Source engine is the Image-Based Rendering system.  The system was due to release back in 2004 with the Half-Life 2 game, however it was struck of the list before the release was set.  Currently Valve is attempting to integrate this feature into their Source engine, as it would allow support for very large scenes that currently are not possible with polygonal objects.

As I stated before, Valves Source Engine is still my favorite engine after so many years of gaming.  The ease of access, the modding capabilities and the optimization are all what give players like myself such a joy from using it.  I can not wait to see what Valve has in store for this engine and what exciting technologies and games they will be able to release in the coming years.  

Half-Life 3 perhaps?