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erikals
05-25-2010, 07:42 AM
curious, anybody understand how it was done?
http://jeremyawon.info/sotcss/making_of_sotc/making_of_sotc.html

http://web.archive.org/web/20060610111558/www.dyingduck.com/sotc/3dwa84.jpg

Jockomo
05-25-2010, 09:28 AM
from what I can tell, they use the lighting in the scene to determine the direction of fall off on the gradient image. So if the scene lighting has a light to the left of the smoke, it creates a gradient image with the light side on the left graduating to black on the right.

Then that image is combined with the smoke image in the sprite, like you would in photoshop with an add or multiply or something.

Finally that adjusted image is used in place of the original smoke sprite, thus giving the impression that the sprite received lighting and cast shadows on itself.

Very interesting technique.

erikals
05-25-2010, 10:32 AM
ah, ok, so sort of like a Z-depth trick, interesting,...
guess it could be improved even further, rendertimes would be super-low.