The next line added retrieves a pointer to the server variable struct, and places it in tROSVars that we declared previously. Now for the actual fog code. The first line delares an array of type GLfloat . By using the GL float type, we ensure our code to be platform and implementation independent. The number in front of each one is the number of bits each is using.
Alpha is a component used for transparency and blending and the like.
The maximum value of each color is 1, which indicates maximum intensity for the color. In our case we are using a grey color, the general color of fog. You will see later that our fog entities support many other colors as well. Where this mode is a simple ratio, the other 2 fog modes use exponential equations which slow fog calculations and make for much denser fog, which to me didn't look good. The last step in the initialization code clears the background color to our fog color.