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Dissecting the Engine and a Brief History 1

Dissecting the Video and a Brief History

Julie Wilmore

Michigan State University

Dissecting the Video Game Engine and a Brief History 2

Abstract

This paper explores the makings of the modern video game engine and the evolution of this technology. Using many online resources, the components of an engine have been explored and explained. This paper also discovers which engines contemporary game developers are using and the supposed advantages or innovative techniques of these major players. This includes a section on the use of as developers are turning more and more often to this resource. A history of game engines is explored to show the evolution of this pivotal piece of software. The engines are described in a chronological order to show the progression though the most recent, what are called -gen games. Dissecting the Video Game Engine and a Brief History 3

Dissecting the Video Game Engine and a Brief History

In the history of video games the all-important engine is crucial to the development of games as we know them. The video game engine is now used by all developers to put together; physics, artificial intelligence, visual assets, rendering, sounds, and levels to make a game. Some developers also use middleware as a fast easy solution to the development process. Basically, the engine is where the whole thing comes together. The game engine can be considered “ all the non-game specific technology” (Simpson, 2002, Part I) that basically pulls all of the actual game materials together to create a game. The game engine is the framework with which a game is built in and around. It is what allows the developer to combine assets and code together to create a cohesive game. This paper will explore what a game engine is made of and which engines developers are choosing to use today. Most game engines have multiple parts that make up the technology. These include a wide variety of functions, which allow the developer and level designer to place and view in real time, what assets look and behave like within the game. Many engines involve around a dozen separate pieces of software, but they all have these parts in common.

The artificial intelligence of a game generally provides guidelines for behaviors including path finding, decision-making, world awareness, and survival techniques

(Simpson, 2002, Part X). Path finding is the general world navigation whether it is to find an enemy, keeping formation (known as flocking), or avoiding obstacles. Decision- making often involves choosing fight or flight, does the NPC (non-playable character) take cover or shoot or run away. World awareness is well explained in an example by Dissecting the Video Game Engine and a Brief History 4

Simpson (2002, Part X) “the situation where two guards are standing next to one another, and you pick one off using a sniping weapon, and the other stands there completely oblivious to what happened.” In this situation there is no world awareness, but if the second guard were to react and shoot back this adds another level of reality to the game.

The scripting editor is another important element of a game engine. The scripting editor allows for even more storytelling devices. Cut scenes are created with scripting and pre-rendering these scenarios in the game renderer. It is also used for coding “what if” scenarios, “Given that we don't know the state of the world when the script commences, we are forced to create a script for almost every eventuality (Simpson, 2002, Part V).”

Visually exciting characteristics add realism and interest to the game. The renderer handles these elements. It relays information from code and makes it into visual data for the player to interpret. Not only does the renderer deal with depth of field and what a viewer can see but it also handles the lighting of a scene, which can stand out if it is off by just a slight amount (Simpson, 2002, Part I). Lighting is also an important element; the renderer calculates how many vertices or planes the light will reach and at what strength. Texture maps add a great amount of realism to the environment, they map color files to objects and Bump maps add texture to surfaces without adding geometry.

With more and more players investing in surround-sound speakers the sound and music in games is becoming increasingly important. This part of the engine even allows developers to associate certain sound effects based on what material an object hits, this is called a sound environment (Simpson, 2002, Part V). Another issue Simpson addresses is mixing the sounds to create a realistic soundscape, “Once you've decided what sounds Dissecting the Video Game Engine and a Brief History 5 you can actually hear based on where you are located, where the sounds are in space, and what the volume is for each sound, then you have to mix the sounds.”(2002, Part V)

Another piece of the engine is the physics. Physics in a game world are rarely identical to real life physics although they are based around the general real life mechanics of physics (Simpson, 2002, Part V). Being able to jump really high and run even faster are more exciting to a player than restricting the characters actions to real world physics. will include collision detection, which keeps characters from walking through walls and falling through floors. Gravity and velocity are also accounted for. One company, NVIDIA Technologies, has created their own chip called

PhysX which is devoted to processing all the physics based calculations and allows the game to simulate more realistic behaviors (Slagle, 2006). “The idea behind PhysX is to take the strain of physics calculations away from the central microprocessor, freeing up all sorts of possibilities in video games” (Slagle, 2006).

The history of game engines began in the 1990’s with the creation of first-person shooters such as . Though the term was coined in the 1990’s there are some examples such as Lucas Arts’ SCUMM system, which came into use in the 1980’s.

Before the invention of the game engine developers had to start from scratch every time they produced a new game. With Doom and the invention of the reusable engine time spent coding the basics was cut significantly. (Lilly, 2009)

Before Doom there was Space Rogue, which eventually became Ultima

Underworld released in 1990. This engine had texturing capabilities, which allowed Dissecting the Video Game Engine and a Brief History 6

Origin Systems to map the environment surfaces (Lilly, 2009). This engine used all 2D sprites but rendered them in 3D.

Similarly, the (1993) by had no 3D capabilities although it cleverly rendered a 3D feeling environment. Many titles were built off of this engine making it the first reusable engine. (Lilly, 2009)

The next major engine was the engine in late 1993. Again this engine used

2D planes and sprites to give the illusion of 3D and allowed the player to look up and down to further this illusion. This engine was made famous by Duke Nukem 3D. Each of these engines so far show the cunning of the people who made them; in Duke Nukem the programmers set up tags in the code so when a player passed a certain spot they would trigger code for “creating holes in the ground that a player would appear to fall through, but really would be teleporting to a different sector on the 2D map.”(Lilly, 2009)

One of the first actual 3D engines was the XnGine released in 1995(Lilly, 2009) It used actual 3D objects, not just sprites, but ran into issues when “clipping issues caused gamers to get stuck on 3D polygonal objects.” (Lilly, 2009)

The release of the engine in 1995 by Lucas Arts was used in only a few games but it was very successful at creating a realistic 3D environment. (Lilly, 2009) It also made popular the crouch and jump commands.

The engine, released in 1996 by Id Software, is important for its slender processing requirements. The rendering processor cut out all the polygons that did not require rendering and by doing so reduced the demand on the CPU.

The Renderware engine is used on quite a few games and is also multi platform including PC, PlayStation 2, “GameCube, , and , PlayStation 3, and Dissecting the Video Game Engine and a Brief History 7

PSP”(Lilly, 2009). A very popular new feature of the engine was the ability for developers to alter art and “game processes” in real-time without having to alter the code.(Lilly, 2009)

When the was released in 1998 began as a mostly first-person shooter(FPS) engine but has gone on to be used in many role-playing games (RPG’s). It has a variety of capabilities including “software and hardware rendering … as well as collision detection, colored lighting, and a rudimentary version of texture filtering” (Lilly,

2009).

Quake III’s release in 1999 brings with it better techniques as well as better graphics in terms of shadows, , and networking capabilities. (Lilly, 2009)

This engine is now known as 3.

The recent GeoMod engine steps up in-game physics making them more realistic and believable. In terms of destructible environments this engine is on top. This engine is best know for the games Red Faction and Red Faction: Guerrilla. (Lilly, 2009)

A popular “hobbyist” engine is the 3D engine released in 2001. According to Lilly (2009),, “One of the highlights of the Torque engine was that it featured an in- game terrain engine capable of manipulating levels of details on the fly so that fewer polygons would need to be rendered.”

A very flexible engine is . It was designed to work across multiple platforms and according to Lilly (2009), “Since the Gamebryo engine was first launched six years ago (2003), Geoff Selzer, president and CEO of Emergent Game Technologies

(developer of Gamebryo), estimates it has been used in the development of around 200 games.” Two notable titles include Oblivion and 3. Dissecting the Video Game Engine and a Brief History 8

Developed by NaturalMotion the engine is capable of creating realistic much more accurate than a typical ragdoll. Euphoria uses no only the skeleton, “but also muscles and the nervous system. Adaptive intelligence modules control how a character moves and adds to the realism more so than what is possible through predefined animations.”( Lilly, 2009) Although commonly seen as middleware

NaturalMotion says that it is not.(Lilly, 2009)

Crytek’s CryEngine has quickly made a name for itself since its release in 2004.

According to Stead (2009), “Unlike many of its competitors, this engine does not need additional support from niche third-party middleware and can handle its own physics, sound and animations, as well as produce the outstanding visuals for which Crytek's games are famed.” Lilly also says that the visual allowed by this engine add “to the level of immersion”. (2009)

The Rockstar Advanced Game Engine (RAGE) is a competitive player in the next-gen engine market. It is easily adapted with middleware like “Euphoria from

NaturalMotion, a dynamic animation engine, bonded with RAGE like they'd been split at birth.”(Stead, 2009)

Unreal 2 and now Unreal 3 (2007) have evolved into even stronger engines than the original. According to Stead, “more than any other middleware solution, it is the

Unreal Engine which has shaped the next-generation visual landscape.” Its titles include

Gears of War, Mass Effect, BioShock, and many others. (Stead, 2009)

The Anvil engine is best known for the interaction between animation and environment as seen in Assassins Creed and Prince of Persia. The smart AI (Artificial Dissecting the Video Game Engine and a Brief History 9

Intelligence) is also a compelling detail it allows for dynamic game mechanics. (Stead,

2009)

In today’s gaming world many developers are resorting to using middleware for their games. Commonly many of these middleware pieces are physics engines although there are others for different uses. Physics engines have become very important aspect of game engines in the past few years with players desiring more and more realistic game play. Nowadays most physics are done with middleware meaning separate engines specifically created to calculate the physics while working with the overall game engine.

This makes calculations easier to perform within the game and facilitate the development process. These engines specialize in the simulation of real world physics in the digital world. Most physics engines have a few special components. They handle basic physics systems including collision detection, object deformation and dynamics. Although they all have these similarities each one handles them in different ways.

A survey conducted by a member of Gamasutra.com found that 55% of the participants are “using a middleware game engine on their current project.” (DeLaura,

2009)This shows that middleware like physics engines are definitely prominent in the game industry. There are many pieces of middleware many of which are physics engines.

The most common pieces of physics middleware are , PhysX, and the Euphoria physics based engines. (DeLaura, 2009) Of these it appears that Havok is the most popular among developers and Euphoria being used in conjunction with Havok seems relatively popular also. Some advantages to using middleware as opposed to starting from scratch are that the programmers are able to spend more time focused on mechanics that Dissecting the Video Game Engine and a Brief History 10 will set the game apart from others instead of worrying about getting it to run the basics.

This allows for faster completion and hopefully and easier or more efficient line of production. Another advantage is that as these pieces of software become more and more standard the likeliness that a new employee is already familiar with the technology becomes greater and greater reducing the time it takes to acclimate to the new companies environment instead of training the employee on a in-house engine. (DeLaura, 2009)

The available from Havok is one of the leaders in real-time physics simulations for games and also some animation and behavior answers. (DeLaura,

2009) It was used in many popular games, many which would be considered ‘hardcore’ and also in other more casual games including Assassins Creed, BioShock, ,

Spore, MySims and many others. One of its major strengths is the cross-platform support available to game creators providing assistance with any issues that may come up.

According to Zogrim, “Havok is currently best choice for AAA titles – extensive toolset , orientation on consoles, best-in-class developer support.”(2009) It uses dynamic simulation to allow for . A ragdoll is when a character or player dies the way it falls and settles to the ground. The support and quick start-up time because it is not proprietary makes Havok a great example as to why many developers are resorting to middleware in their game development process.

A widely used physics engine in the PC market is the PhysX engine. Although

Havok is generally given credit as most used engine it dominates the console realm while

PhysX seems to have taken its hold on the PC market. (Zogrim., 2009) Its use is also expanding according to Zogrim, “Adoption of PhysX SDK is showing substantial growth on whole lifecycle, regardless of engine updates absence.” (2009) Dissecting the Video Game Engine and a Brief History 11

Considering that current developers who use and make game engines are looking to make money from their software many of the specifics are not available to the public.

The lack of accurate and detailed information both on the technical aspects and the few studies on popularity results in a fragmented understanding of how the engine affects the development of video games.

All in all, game engines are complex and simple at the same time. The coding required to create one seems intense but when it is accomplished engines make the whole development process that much easier. In the history of engines from pseudo-3D PC engines to full 3D engines designed for consoles many alterations have been made, but the goal remains the same: make the development process simpler. In the highly competitive video game industry it makes complete sense to create reusable engines that not only can be used again to create even more games (including sequels) but it can also be licensed to other developers for a fee. The evolution of game engines is moving towards more realistic games in physics, sounds, and rendering. This more realistic experience is a major factor in gaining new and keeping old consumers hooked. Dissecting the Video Game Engine and a Brief History 12

References

DeLaura, Mark. March 16, 2009. The Engine Survey: Technology Results. Retrieved

from http://www.gamasutra.com/blogs/MarkDeLoura/20090316/903/

The_Engine_Survey_Technology_Results.php.

Lilly, Pauly. July 17, 2009. Doom to Dunia: A Visual History of Game Engines.

Maximum PC. Retrieved from http://www.maximumpc.com/article/features/3d

_game_engines?page=0%2C0.

Simpson, Jake. July 11, 2002. Game Engine Anatomy 101. Retrieved from http://www.

extremetech.com/article2/0,2845,594,00.asp.

Slagle, Matt. June 20, 2006. Physics may take video games to next level. USA Today. Retrieved from

http://www.usatoday.com/tech/gaming/2006-06-20-physics-gaming_x.htm.

Stead, Chris. July 15, 2009. The 10 Best Game Engines of This Generation: Without

guts, there can be no glory: from Anvil to Unreal. Retrieved from http://pc.ign.

com/articles/100/1003725p1.html.

Zogrim. December 7, 2009. Popular Physics Engines comparison: PhysX, Havok and ODE.

Retrieved from http://physxinfo.com/articles/?page_id=154.