Valve's High Dynamic Range Explored@ 2005/10/01
That's right, Valve has updated their source engine to enable something called High Dynamic Range, and the first two applications to implement this are Day of Defeat (a popular Half life 2 mod) and the upcoming new level for Half life 2: the Lost Coast. High dynamic range is basically a more realistic way to implement lighting in a three-dimensional world. With HDR, light sources will appear brighter, and other effects like blooming are possible. HDR, along with other things like auto-exposure, take lighting to a new level, further enhancing the realism of a virtual world. To give you a better idea of the concept behind HDR, here is a quote from Paul Debevec:
"The 'dynamic range' of a scene is the contrast ratio between its brightest and darkest parts. A plate of evenly-lit mashed potatoes outside on a cloudy day is low-dynamic range. The interior of an ornate cathedral with light streaming in through its stained-glass windows is high dynamic range. In fact, any scene in which the light sources can be seen directly is high dynamic range."
Obviously, one of the first things that we were concerned about regarding this upgrade was how this would affect performance. We weren't sure quite what to expect, but we did some testing on multiple ATI and NVIDIA graphics cards, and we'll take a look at the results later on. First, let's go a bit more in-depth into the technology.