Source (game engine) facts for kids

Quick facts for kids
Source

Developer(s)	Valve
Initial release	October 2004; 20 years ago (2004-10)
Written in	C++
Middleware	Havok
Predecessor	GoldSrc
Successor	Source 2
License	Proprietary

Source is a special computer program called a game engine. It was made by a company called Valve. This engine helps create 3D video games. Source first came out in October 2004. It was used for games like Half-Life: Source, Counter-Strike: Source, and Half-Life 2.

Valve used the Source engine for many of their popular games over the years. These include Team Fortress 2, Counter-Strike: Global Offensive, Dota 2, and the Portal and Left 4 Dead game series. Other game makers also used Source for their games. Some well-known ones are the Titanfall games, Vampire: The Masquerade – Bloodlines, Dear Esther, The Stanley Parable, and Garry’s Mod. Valve kept updating Source until a newer engine, Source 2, took its place in 2015.

How Source Began

The Source engine actually grew from an older engine called GoldSrc. GoldSrc was a changed version of the Quake engine, which was made by John Carmack. Carmack even said in 2004 that parts of the original Quake code were still in Half-Life 2.

A Valve employee named Erik Johnson explained how Source got its name. He said that before Half-Life was released, Valve needed to work on new projects. They created two separate versions of their game code. One was called "Goldsrc" for the game that was already out. The other was called "Source" for new, more experimental technology. When they showed Half-Life 2 for the first time, they called its engine "Source" to tell it apart from the "Goldsource" engine. The name just stuck!

Source was built piece by piece from this starting point. It slowly replaced GoldSrc in Valve's projects. This is why Source is made of many different parts that can be updated separately. Valve used a mix of licensed tools and their own code to build Source. Older versions of Source used Bink Video for videos. Newer versions use WebM videos for things like menu backgrounds and splash screens.

How Source Changed Over Time

Source was designed to get better with small updates. It didn't need big, sudden changes that would break older games. Different parts of Source are like separate building blocks. These blocks can be updated on their own. With Steam, Valve could send these updates to players automatically.

Sometimes, though, updates did cause small problems for older games. When Half-Life 2: Episode One and The Orange Box came out, they brought new versions of the engine. Older games or mods needed updates to work with these new versions. But it was still much easier to update Source games than games made with other engines.

Source 2006 Updates

A scene from Half-Life 2: Episode One. You can see the improved lighting and shading effects.

The Source 2006 updates were for games like Half-Life 2: Episode One. In 2005, new lighting effects like HDR rendering and color correction were added. These first appeared in Day of Defeat: Source. They made the game's graphics look much better. Half-Life 2: Lost Coast also showed off these new lighting effects. Episode One added even more detailed shading called Phong shading.

Source 2007 Updates

The Source 2007 updates were a big improvement for the Source engine. They came with The Orange Box games. A new system for particles (like smoke or explosions) was added. This system was more flexible and could be controlled by artists. Tools were also made to help create these effects. The system for character facial animations also got much better. It could now create movie-quality faces.

The Orange Box was released on many different game systems. This helped Valve make the engine work better with multiple CPU cores. This means the engine could use more of a computer's power. This feature was later added to Team Fortress 2 and Day of Defeat: Source. Valve also made the Xbox 360 version of The Orange Box themselves. This made sure the engine worked well on that console.

Left 4 Dead Engine Changes

The Left 4 Dead games brought many more changes to the Source engine. Support for multiple processors was improved even more. This allowed for features like split screen multiplayer. It also added new visual effects and a special AI Director. The AI Director could change the game's difficulty based on how players were doing. The game's menu also got a new look, designed to be easier to use on consoles.

These changes were later used in Alien Swarm and Portal 2. Alien Swarm even came with its source code, showing many of the updates. Portal 2 was the first game where Valve handled the PlayStation 3 version themselves. They made it work very well with Steamworks.

Source on Other Systems

In April 2010, Valve released their main Source games on OS X (Apple computers). They said all future games would come out for both Windows and Mac at the same time. Team Fortress 2 was the first Valve game to support Linux in October 2012. Both the OS X and Linux versions of the engine use OpenGL for graphics.

While porting games, Valve organized their game code into "singleplayer" and "multiplayer" versions. These versions were made public for mod developers in 2013. They are still the main versions of Source used for mods today. Support for Valve's Steam Pipe system and the Oculus Rift (a virtual reality headset) were also added. In May 2014, Nvidia released Portal and Half-Life 2 for their Tegra 4-based Android device, the Nvidia Shield.

Source 2 Engine

Source 2 is the engine that came after Source. Valve announced it in March 2015. They said it would be free for game developers to use. It also supports a new graphics system called Vulkan. Source 2 uses a new physics engine called Rubikon.

In June 2015, Valve announced that Dota 2, which was made with the first Source engine, would be updated to Source 2. This update was called Dota 2 Reborn. Reborn was first available as a test version. It officially replaced the old game in September 2015. This made Dota 2 the first game to use the Source 2 engine. Source 2 had fully replaced the original Source engine by the late 2010s.

Tools for Making Games with Source

Source SDK

The Source SDK is a set of tools for the Source engine. SDK stands for "Software Development Kit." It has many programs that Valve used to create their games. It includes tools that run from the command line for special tasks. It also has programs with a graphical interface for more complex jobs.

The Source SDK was first a free toolset on Steam. You needed to own a Source game to use it. After Left 4 Dead came out, Valve started releasing "Authoring Tools" for each game. These were the same programs, but made for that specific game's engine. When Team Fortress 2 became free to play, the Source SDK became available to all Steam users. Later, when some Source games were updated, the older SDKs were replaced. Now, the main tools are included when you install each game.

The Source SDK includes three main applications: Hammer Editor, Model Viewer, and Face Poser. The Model Viewer lets you look at 3D models. Game developers use it to see models, their animations, and how they are put together. Face Poser is used for character facial animations and movements. It helps you create and arrange facial expressions, gestures, and even lip-sync speech for characters. You can see how the scene will look in the game.

Hammer Editor

The Hammer Editor is the official tool for making levels (or maps) in the Source engine. It uses special tools to create maps using a method called binary space partitioning (BSP). You build the level using 3D shapes called brushes. Each side of a brush can have a texture. This texture also tells the game things like what sound footsteps should make on that surface. You can also turn parts of brushes into "displacements" to make natural shapes like hills.

You can also add scenery objects or complex shapes as separate 3D models. These models can be used as objects that react to physics or interactive items. The editor also has a detailed system for creating complex interactive parts. You can set up signals between objects like buttons, NPCs (non-player characters), and props. These signals can trigger different actions or change how an object behaves.

Source Dedicated Server

The Source Dedicated Server (SRCDS) is a program that runs multiplayer game sessions for the Source engine. It doesn't need the game client to be running. It can be used on Windows or Linux. It also allows for custom levels and game content. Many third-party servers use other tools like Metamod:Source and SourceMod. These tools add more ways to change how the game plays.

Source Filmmaker

Source Filmmaker (SFM) is a 3D animation program built right into the Source engine. Valve made this tool. They used it to create videos for games like Day of Defeat: Source and Team Fortress 2. It was also used to make some trailers for Source Engine games. SFM was released to the public in 2012.

Destinations Workshop Tools

In June 2016, Valve released the Destinations Workshop Tools. These are free tools for creating virtual reality (VR) content. They run using the Source 2 SDK.

Valve Developer Community

In June 2005, Valve started the Valve Developer Community wiki. This website replaced Valve's old documentation for the Source SDK. It's a community site powered by MediaWiki. It's a great place for developers to find information and help each other.

Games Made with Source

The games Titanfall, Titanfall 2, and Apex Legends are not listed here. Even though their engines started with Source, they were changed so much that they are now considered different engines.

See also

In Spanish: Source para niños

• First-person shooter engine
• List of Source engine mods