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

The Source engine is a special computer program. It helps game developers create amazing 3D games. Valve, a famous game company, made this engine. It first appeared in 2004. This was with games like Half-Life: Source, Counter-Strike: Source, and Half-Life 2.

Source is well-known because Valve uses it for many of their games. But other game makers also use it. Even small teams and individuals use it to make their own game versions. One famous game not made by Valve using Source is Vampire: The Masquerade – Bloodlines. Valve kept adding new features to the Source engine over the years. Later, Valve created a new engine called Source 2. It took over from Source, starting with Half-Life: Alyx. The Source engine is famous for its cool physics, smart computer players (AI), and awesome graphics.

How the Source Engine Started

The Source engine actually grew from an older engine called GoldSrc. GoldSrc was a changed version of the Quake engine. This means some of the original Quake game code was still in Half-Life 2.

A Valve employee named Erik Johnson explained how the engine got its name. When the first Half-Life game was almost ready, Valve needed to start new projects. But they couldn't risk changing the game that was about to be released. So, they made two copies of the code. One was called `/$Goldsrc` and the other `/$Src`.

For a few years, they called these "Goldsource" and "Source" inside the company. Goldsource was the code for the games already out. Source was for the newer, more experimental technology. When they showed Half-Life 2 for the first time, they used the names "Source engine" and "Goldsource engine". The name "Source" just stuck!

From then on, Source was built piece by piece. It slowly replaced GoldSrc in Valve's projects. This is why Source is made of many separate parts. Valve built Source using a mix of their own code and tools from other companies. Older versions of Source used Bink Video for playing videos. Newer versions use WebM videos for things like menu backgrounds.

How Source Changed Over Time

The Source engine was designed to get better bit by bit. It didn't have big, sudden "version jumps" like other engines. Instead, different parts of Source are separate. This means they can be updated on their own. With Steam, Valve could send these updates to players automatically.

However, sometimes these updates caused small problems. For example, when Half-Life 2: Episode One and The Orange Box came out, they used new engine versions. Older games or fan-made mods sometimes needed updates to work. But it was usually much easier to update them than with other game engines.

Source 2006 Updates

A screenshot of Half-Life 2: Episode One. Notice the bright and dark areas (HDR) and smooth lighting (Phong shading).

The Source 2006 updates were used in games like Half-Life 2: Episode One. In 2005, new lighting effects were added. These included HDR rendering (making bright and dark areas look more real) and color correction. These changes first appeared in Day of Defeat: Source. They made the engine's graphics code need to be rewritten.

HDR lighting was shown off in Half-Life 2: Lost Coast. Episode One also added Phong shading. This made objects look smoother and more realistic.

Source 2007 Updates

The Source 2007 updates were a big improvement for The Orange Box games. A new system for particles was added. This made effects like smoke or explosions look much better. It also helped create the first versions of Source Filmmaker.

The system for character facial animations also got better. It could now use your computer's graphics card. This made faces look almost as good as in movies! The Orange Box came out on different game consoles. This helped Valve make the Source engine use multiple parts of your computer's brain (CPU cores). This made games run smoother.

At first, using multiple CPU cores on PC was a bit tricky. But it got much better with Left 4 Dead. Later, this improvement was added to Team Fortress 2 and Day of Defeat: Source. Valve also made the Xbox 360 version of The Orange Box themselves. This meant the engine worked great on that console.

Left 4 Dead Engine Changes

The Left 4 Dead games brought many big changes to the Source engine. It got even better at using multiple CPU cores. This allowed for cool features like split-screen multiplayer. It also added more visual effects and a smart AI Director. The AI Director could change the game based on how players were doing.

The game's menu also got a new look. It was made to be easier to use with game controllers. This updated engine was also used for Alien Swarm and Portal 2. Portal 2 was a big success for Valve. They managed to make a great version for the PlayStation 3 console.

Source on Other Devices

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. The first Valve game to work on Linux was Team Fortress 2 in 2012. Both the OS X and Linux versions use OpenGL and Simple DirectMedia Layer.

While porting games, Valve organized their game code. They made separate "singleplayer" and "multiplayer" versions. These versions were made public for mod developers in 2013. They are still used for many mods today. The engine also got support for Oculus Rift virtual reality headsets. In 2014, Nvidia released Portal and Half-Life 2 for their Tegra 4-powered Android handheld game console Nvidia Shield.

Source 2: The Next Generation

Source 2 is the engine that came after Source. Valve announced it in 2015. They said it would be free for game developers to use. It also supports the Vulkan graphical API. This is a new way for games to talk to graphics cards. Source 2 also uses a new physics engine called Rubikon.

In 2015, Valve announced that Dota 2 would move to Source 2. It was originally made with the first Source engine. The update was called Dota 2 Reborn. It was the first game to use the new Source 2 engine. By the late 2010s, Source 2 had mostly taken over from the original Source engine.

Tools for Making Games with Source

Source SDK: The Developer's Toolkit

The Source SDK is a special set of tools. It's like a toolkit for making games with the Source engine. Valve used these tools to create their own game content. The SDK includes programs that run from the command line. It also has programs with a graphical interface (GUI) for more complex tasks.

The Source SDK used to be a free tool. 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, the Source SDK became available to all Steam users. Later, older Source SDKs were replaced. Now, the main tools are included when you install each game.

The Source SDK has three main programs:

• Model Viewer: This program lets you look at 3D models. Game developers use it to check models, their animations, and how different parts connect.
• Face Poser: This tool helps create character facial animations. You can use it to change expressions, gestures, and movements. It also helps make characters' mouths move with speech (lip sync). You can see how the scene will look in the game.

Hammer Editor: Building Game Worlds

The Hammer Editor is the official tool for designing game levels. It uses special tools to create maps. These maps are built using a method called binary space partitioning (BSP). You create the level using 3D shapes called "brushes." Each side of a brush can have a texture. This texture also tells the game how the surface behaves. For example, what sound footsteps make on it. You can also turn faces into "displacements." This helps create natural shapes like hills.

You can also add scenery objects or complex shapes. These are imported as separate 3D models. These models can also be physics objects or interactive props. The editor also has a detailed logic system. This lets you create complex interactive parts. You can send signals between objects like buttons, NPCs, or props. This can trigger different actions or change how something works.

Source Dedicated Server: Hosting Games

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

Source Filmmaker: Making Movies

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

Destinations Workshop Tools: VR Creation

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: Learning Hub

In June 2005, Valve started the Valve Developer Community wiki. It's a website where developers can find information and share knowledge. It replaced Valve's old documentation. It uses MediaWiki, which is the same software Wikipedia uses.

Academic Papers: Sharing Knowledge

Valve staff have sometimes written papers for events like SIGGRAPH. These papers explain different parts of how the Source engine was made.

Famous Games Using Source

Games like Titanfall, Titanfall 2, and Apex Legends are not on this list. Their engines started from the Source SDK. But they were changed so much that they became completely different engines.

See also

In Spanish: Source para niños

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