Anybody that have played game like gt3 will see that there''s sun reflection on the road surface that is very realistic. With close examination i found out that only certain pixel on the road surface reflect the light giving you the impression that the road surface is coarse. Do anybody knows how they do that? Do they use bumpmap or other method? I really like to do it in my project.

Can you post a picture of the effect?

It's difficult to see the sun refection on a static picture so i put a picture of light reflection on a wet road but i think the way they used to make the effect is same (picture from ps2.ign.com)




[edited by - ctoa on July 19, 2003 8:36:34 PM]

It seems to be only a detail texture over the base texture...
That would be my guess, but I might be wrong...

it''s specular light component

I am pretty sure it''s bump map..

I am pretty sure it's bump map.. You can create a bump map easily with noise effect in Photoshop. However, I think applying bump map with OpenGL can be a bit tricky.. Has anyone find a way how?

[edited by - Xenogear on July 20, 2003 7:09:19 PM]

That is no bumpmap.

there is however a way using the stencil buffer(well in theory anyway).

step 1. Render the wet spot's on the ground to the stencil buffer(not to the color o depth buffer).

step 2. while using the stencil buffer, render downwards( to the botom center of the screen )streaking flares from all the lightpoints(no deapth buffer thingey here).


That might even be the way they made it(the ps2 uses a GF2 and has no pixelshaders).
If you look closely on the image then you will see that the light reflections are only comming from the lights with flares(ie. all lightposts) and not the buildings though some of them are well lit up.
This is consistant with the way i mentioned, allthough it might need some tweaking. =)

[edited by - lc_overlord on July 21, 2003 6:33:25 PM]

Are those real time rendered reflections, or just environment maps?

Neither, it''s just an VFX.