Half-Life 2’s new commentary mode reveals the origins of the Source engine’s iconic neon fuchsia texture.

It's strange to say, but the error textures on Valve Source engine feel like old friends to me. Its black and fuchsia checked pattern is a familiar one that appears everywhere, from Counter-Strike surf maps to bootleg Mario Kart in Team Fortress 2 maps. It's a clever reminder of a beloved FPS. It reminds us of the "FIREBLU", a similar ugly-cute lava texture in Doom. Valve has now explained the reasoning behind the now-iconic error image in the 20th Anniversary Developer Commentary for Half-Life 2.

The relevant part of the commentary is at the beginning of Half-Life 2 in the tenement before the Combine raid starts. Valve's senior software engineer Jay Stelly talks about the texture and shows a short example of it.

Shelly explained that "early on, when developing our low-level graphic code, we realized that it would be hard to spot polygons which were not rendering due to missing textures," she said. "When this happens, you would typically see black where the texture should be. This could easily go undetected in some darker scenes. To detect this bug more reliably we created a error texture that was visually unmistakable. It is generated automatically when a texture fails to load.

This texture has become iconic and is used in many other games, including Half-Life 2.

The "beyond Half Life 2" line is right on target--I can't remember seeing the texture in the campaign at all (so it must have done its job). Most people associate it instead with mods and other non-Valve Source titles, especially the crazy and flexible Garry's Mod. You'll notice neon checkerboards in place of walls or floors, and even entire skyboxes, if you have a version of Garry’s Mod. It could be a bug in a custom map, but it's more likely that the game is trying to load textures that you don't have access to. For example, if you own Half-Life 2 or Team Fortress 2, but but not Counter-Strike Source, you would see checkerboards and errors as far as your eye can see.

The image of a glitched-out level made up of this eye-searing pattern is a meme favorite. Its nostalgic liminal quality, coupled with its patent absurdity, makes it a perfect match with Kramer explaining to Jerry what lies behind a glowing frame, or Ryan Gosling in Blade Runner 2049. This is another example, along with--I'm so sorry--Skibidi Toilet, of the enduring influence of Half-Life and Source engine all these years after the games themselves. I prefer Valve's disco neon dream over the Unreal Engine's version, which is a weird mold texture from 1995.