At the two minute mark Josh says, “What’s up with the lighting on this thing?” He’s looking at a closed door that mysteriously has bright light flowing through it. The image doesn’t make sense until the zombie breaks the door. I know Chris already explained it a bit, but let me go over it in more detail:
This is a side-effect of the old 1990’s style baked-in lightmaps. Computers weren’t fast enough to recalculate lights on the fly, so the shadows are calculated by the artist before the game ships. This means the shadows can’t move. The shadows that do move – the shadows cast by the NPCs and objects in the scene – use a completely different technology. As Alyx walks around, the game picks the nearest light source and creates a silhouette of her from the viewpoint of that light. It then projects that silhouette onto the groundIt might do this for the nearest two or three light sources, depending on the game and your graphics settings.. The drawback is that these shadows don’t really match the baked-in shadows. They’re crisper, and so the shadows cast by the level geometry (walls and floors and such) look blurry by comparison.
Also, the two different lighting systems don’t react to each other properly. If I’m standing under the midday sun, then I’ll have a shadow at my feet. If I step under an umbrella, then my shadow will vanish behind the shadow on the umbrella. But Alyx’s shadow doesn’t work that way. It’s always there, regardless of where she’s standing in relation to the light.
This was why Carmack was so excited about the idea of “unified lighting” in Doom 3. There was no longer one system of lighting for the level and another for all the characters and props. There was one lighting system shared by everything, and it all worked together.
Half-Life 2 has aged really well, but I guess there’s limits on everything. It was 2006 when this game came out, and its lighting model was already pretty far out of date. Valve wouldn’t really solve this issue for good until Portal 2, five years later.
Also, while Valve does seem to love their seesaw puzzles a little too much, I just can’t bring myself to get mad about them in a world where Ubisoft makes me climb a hundred and fifty identical towers in every stupid game.
The next episode is the end of Episode One.
 It might do this for the nearest two or three light sources, depending on the game and your graphics settings.
Grand Theft Railroad
Grand Theft Auto is a lousy, cheating jerk of a game.
Why Google sucks, and what made me switch to crowdfunding for this site.
Top 64 Videogames
Lists of 'best games ever' are dumb and annoying. But like a self-loathing hipster I made one anyway.
Bethesda NEVER Understood Fallout
Let's count up the ways in which Bethesda has misunderstood and misused the Fallout property.
Please Help I Can’t Stop Playing Cities: Skylines
What makes this borderline indie title so much better than the AAA juggernauts that came before?