Ive been playing with OpenGL for a while now and I have a few things I
have seen in games that I would like some info so I can experiment with
1) volumetric lighting - is this what the dusty yellow lighting in the
first level of Unreal is ? Ive heard or various methods to achieve this
effect, including tracing from the point of view to a fog volume object
and measuring the length of intersection to generate a fog map of sorts.
Seems kind of expensive. How does Unreal do it ? is there a way to make
use of the hardwares linear fogging abilities? Maybe rendering a
transparent sphere with fog turned on after rendering the scene with fog
off ? etc.
2) Unreal's shadows - again the first area, there are shadows projected
from the spinning fans in the ceiling. I am going to assume this is also
some sort of animated light/shadow map since it only seems to render on
planar surfaces. ?
3) underwater shimmering - again, lightmaps ?
I need some more info on the BSP and PVS system used for drawing scenes
in games. I understand the basics but I still need to tie everything
Does this system work the same for outdoor terrain oriented scenes such
as those in tribes?
Also I would like some info on collision bounding within a game map, ie:
cant walk through pillars, you walk upward when going up a slope, have
to crouch to go under things, etc. In tile based 2D games youd have an
array the same as the tile array with properties for each tile. What is
the standard way to make a 3D world physically solid ? esp important are
outdoor terrains of rolling hills where the player can move up and down
as it walks across the ground, something like Zelda 64.
All the special FX seem to involve lightmaps. I would like some info on
how to create static lightmaps at map compilation, and managing dynamic
light maps from say, shadows, rockets, etc, and how these are applied to
And lastly, what order is best for a rendering pipeline ? I would think
drawing the level first, applying all lightmaps, textures, etc, then
drawing all objects and players, casting shadows, and last any fancy
I dont expect any one indivudual to answer all these questions, so if
anyone can address any of these topics that would be great. Thanks