RE: [Algorithms] Lightmap Terrain

[Bernd K. <bk...@lo...>]

Charles Bloom writes:
 > The more I look at real outdoor environments (eg. life) the
 > more I feel that it may be hopeless to simulate them realistically
 > on a computer screen.  The problem is the sun. 

Isn't the Sun just a special case of a general problem:
the way we handle dynamic range between graphics card and CRT's? 

Quake3 has a concept of "overbright" (subdividing the dynamic
range to reserve some for intense light sources). Extending the 
color channel range in processing paths in 3D accelerators, 
or using e.g. 16bit float per color channel in framebuffers
might be a way to do this for real. Ultimately, if you want to 
model a flash grenade, you might find this even more 
difficult - and you might not want to model its effects to 
accurately anyway.


 > IMHO this is orders of magnitude more important to visual 
 > realism than radiosity on landscapes.  

Radiosity was used for Q2, and dropped for Q3, seemingly
because it made the job of the map designer harder. One
example that creating environments is still seen to be 
more about control than consistency.

I am not sure how far you want to push visual realism
(and I am confident that it is a red herring at best,
and a hazard at worst, when it comes to creating immersive
environments), but IMO games have already done good jobs 
with these effects. Personally I find the Halo/Sun effects
in Heretic2 well done. You can use particles to do specular
glitter on water or snow. What's missing is the intensity,
a bigger dynamic range at the top, isn't it?

I also think that physiology simulation might be just as 
essential for the reaslism you strive for: if the player 
moves from bright outdoors to dimly lit indoors, do you 
gamma correct to account for the adaptation period? Do 
you change gamma to create pale outdoors when the Sun comes 
out behind a cloud, or blend to change colors? Simulating 
the eye might be more effective than simulating the world.

Anyway, I would expect effects like refraction and 
dispersion to be more challenging. Not to mention 
relativistic FOV distortion and Doppler shift ;-).
Realism is such a wide scope, you gotta fence it 
with relevance...



                                         b.