Game Development Reference
In-Depth Information
8.3 SPECTRUMS, COLOR, AND LIGHT
Sunlight travels to us in a spectrum of wavelengths that are revealed in numerous ways. We see color on
objects because the surface relects that wavelength back at us and absorbs all other wavelengths (i.e., a red
ball only sends red wavelengths back to our eyes). When we put a piece of blue glass or gel in front of a stage
light, the light beam is blue because the colored ilter absorbs all the other wavelengths of light, letting only
the blue light pass through it. Color sensitivity is wired deep in our brains because our survival depends on
it. Think of stoplights and other color-coded symbols so prevalent in our lives and realize that these colors
also have deep emotional connections. The color of passion or love is red, hatred is black, and envy is green.
When you weave these cultural and emotional connections into your lighting design, it becomes all that
more powerful. Ask yourself: Would it be possible to have a depressive orange color or a happy blue color if
I needed it? Making these kinds of sophisticated lighting design choices plays against the obvious assump-
tions and deepens the experience for the visitor to your virtual environment.
In a virtual world, the images of the environments we light are made from a combination of the red,
green, and blue diodes on the screen's surface. These computer screen diodes, interestingly enough, mimic
the color-sensing cones inside our eye structure that are sensitive to red, green, and blue frequencies, respec-
tively. When various amounts of these three colors are mixed, the entire spectrum of colored light and its
colored environment can be displayed for us on the screen's surface. Figure 7.1, the components of color,
shows the additive color model (lower right). There you can see how red mixed with green will create amber
yellow, how red and blue will make magenta, and how green and blue will make cyan. All three together
will make a white color that our eye cannot distinguish from the white color we see under full-spectrum
sunlight [2].
The color of light in the real world changes throughout the day and is measured by a standard called
“color temperature.” This phenomenon is imitated in the Second Life WindLight system. As you can see
from Figure 8.1, the color temperature and color of the light change dramatically during the arc of a virtual
day. During the midday period, the light has a high color temperature number of 5,500-10,000 K (Kelvin
temperature scale) and creates a “cool color” in the bluish range to our eyes (12 p.m., top picture). Conversely,
sunrise and sunset lighting produces a “warm-color” or yellow-orange light to our eyes but has a low color
temperature number of 2000-3000 K.
The color temperature changes that we see during the course of our day are something worth consider-
ing when we design lighting for a virtual world such as Second Life and OpenSim. The WindLight system
found in Second Life and Open Sim are useful design tools. They are always running in the default cycle
unless you have set your virtual land to a ixed sky or you have designed a speciic WindLight setting for your
virtual environment and ask that your visitors utilize it in their viewers. Because this system affects the work
of designers, artists, and photographers, learning how to manage the color temperature of the WindLight
settings is of paramount importance. Note, LightShare is the OpenSim term for WindLight.
8.4 SPACE TO COLOR TO LIGHT: FORMING A LIGHTING METHODOLOGY
Developing a strong, eficient methodology for lighting your virtual environment comes from the practice of
observing space and relating it to your decisions about illuminating the meaning, supporting the mood, and
augmenting the visual style.
Ask this question: What kind of lighting progression is needed in this space, and how will it support
the meaning and mood? Of course, in virtual environments, this can vary wildly. A irst-person shooter
game needs a progression of illumination that supports the game play by allowing the player to ind the
