Lighting and Interactivity
The next thing that Tim pointed out is that EVERY single light in the game is dynamic, not just casting areas brighter indiscriminately, but having a real effect on all objects in the game, casting real shadows. Every light in the game can be shot out as well, although doing so would make it a lot more difficult to spot enemies. Speaking of which, we got treated to an old friend from Doom 2 - the Revenant. The Doom 3 version has twin shoulder mounted rockets, which it fired liberally as it chased Tim around the level. We did notice a little bit of hitching on the machine as rockets were fired and smoke trails criss-crossed the map.
Next, Willits talked about the physics engine in the game, once again demonstrating on a fat zombie, killing it on a short staircase. The zombie displayed "rag-doll" physics similar to that demonstrated by Epic in their Unreal engine technology demos. That is, the body did not lie perpendicular to the floor, hanging over the edge of the stairs and "defying" gravity as you may have seen in many current games. Rather, the body slid down along the staircase as it was shot, lying diagonally across the irregular surface just as you'd expect. The physics engine considers even dead bodies as a skeletal system with relative weights, so there is no strange overhanging or clipping. Likewise, other objects in the game are subject to the physics engine, like boxes shot off of shelves, and light fixtures shot up from their hanging joints. And with the Doom 3 engine's superior handling of direct light sources, a lamp shot from its fixture so that it swings back and forth will indeed cast shadows that lengthen and contract from characters and objects in the room, relative to position.
Willits also demonstrated that a texture overlay can be placed on lights to create an even moodier atmosphere. For instance, there was a metal grating overlay on the light source that casts everything with a striping, windowblind shadow pattern. Those who have seen the movie Aliens would be familiar with the effect such a texture might create. It's also similar to the album cover of the Cure single, "Let's Go To Bed.". The best part about the light source texture overlays is that the cast dynamically and correctly across objects and character models that run across the room!
One of the final things that Willits demonstrated was that id is testing out new ways of presenting information to the player. As new objectives are given, you are shown an actual screenshot of the objective. For example, if the next goal is to shut off a computer system, a screenshot of that computer system appears in the top right of your screen so you know exactly what you're looking for. Perhaps more interestingly, the computer consoles that you interact with in the game operate like a GUI. Clicking on a console doesn't take you out of the game and bring up the computer screen, enlarged on your monitor. Instead, you remain in the game engine. Mousing over the console causes you to drop your gun, and the cross hair becomes a mouse you can use to click options on the GUI presented to you. This type of an interface keeps the player immersed in the game.