What is DirectX? Why does every PC game need it?

If you’ve been PC gaming at all over the last 30 years, you’ve probably come across a mention or two about DirectX. Maybe in the form of an error code from a buggy game, or during the rapid-fire succession of windows that open and close during the installation of something from Steam.

With games being made by different studios all over the world, and everyone’s PC holding a different combination of hardware, the sheer ubiquity of DirectX is interesting, and hints at its purpose. So, what is DirectX? And why is it so important? Let’s take a look.

DirectX is a collection of APIs that act as an interface between games and a PC's hardware. This enables game developers to program games without needing to know the specific CPU, GPU, RAM, motherboard, or other components in any given PC.

DirectX is a middleman between the hardware drivers and the game. The game and the hardware drivers do not need to be programmed to work together directly. As long as both are compatible with DirectX, it will translate between the two seamlessly.

If not for DirectX, developers would have to write code for specific hardware combinations, which is exactly what they used to do, at least for a few of the more popular brands. Given the sheer variety of available hardware now and the number of developers, this would be an insurmountable task today.

In short, DirectX ensures that no matter what hardware combination you have in your PC, any game will work, as long as the hardware and the game are compliant with the same version of DirectX.

If you’ve ever felt nostalgic and dug out the disc for a game from 2003, only for your PC to outright reject the installation, this is why. That game was developed to be compliant with the version of DirectX at that time.