6 replies to this topic

[starstutter]

I've got a few questions that maybe a few people with more official business experience can answer. They have to do with techniques that are currently being used in commercial games:

- are we already using things like Oren-Nayar and Cook Torrence as a replacement for Lambert and phong shading? Or are they too slow for complex scenes in current-gen

- are there any games at all that use ray-tracing? What comes to mind is the light beams in Crysis.

- are Shperical Harmonics being used in practice (as in already released games), or is this more a promise for future visuals?

EDIT: One specific thing I'm wondering is if Oren Nayar shading was used on cloth materials in Medal of Honor Airborne. I know it uses Unreal.

[Zuka]

I'm not sure, but I'm quite sure a few games do use raytracing. I think for sure that Half-Life 2 uses raycasting, though.

[starstutter]

Zuka said:

I'm not sure, but I'm quite sure a few games do use raytracing. I think for sure that Half-Life 2 uses raycasting, though.

Maybe brush up the termonology lol? Maybe you meant something different. Raycasting was used in the first Wolf-3D

[.oisyn]

The difference between raycasting and raytracing is more along the lines of that casting a ray is basically a one-shot operation - you fire a ray, and see where it ends up or where/whether it intersects something. Whereas for raytracing, you actually continue to trace the ray after it hits something (like for reflection, refraction and lighting).

Btw, spherical harmonics (or rather: precomputed radiance transfer - spherical harmonics is just a mathematical way to describe a function of something on a sphere, it's not a lighting technique in itself and can be used for dozens of calculations involving, well, spherical harmonics ) is basically pretty "prev-gen" . We used it a lot in our later Xbox and PS2 titles. I'm not saying it is now obsolete btw, it still yields good results, especially combined with modern next-genish techniques.

[TheNut]

Is it even necessary to use lighting models like Oren and Cook when you're dealing with high quality normal maps and textures? You can only squeeze so much out of a pixel ;)

[starstutter]

TheNut said:

Is it even necessary to use lighting models like Oren and Cook when you're dealing with high quality normal maps and textures? You can only squeeze so much out of a pixel ;)

idk man, I've done rendering of things like cloth, stone and dried clay with both models. Oren-Nayar / Cook-Torrance looks WAY better on those surfaces. Especially when you put them into motion. And if you're trying to render something like velvet, the standard lighting won't even make it remotley recognizable. I think the whole point of graphics is so the player doesn't have to use his imagination ;)

[Zuka]

You have to forgive me, I'm only 12.