How is this technique coded using multiple texture passes ? Any links / descriptions ? Thanks, Chris

You can learn the maths theory and some pictures explaining both Dot3 and Emboss bump mapping there :


http://homestead.dejanews.com/user.simonf/files/bumpcomp.htm

notice that Simon Fenney is a engineer working for Imagination technologies which are responsible of the PowerVR.
PowerVR can be found in the Dreamcast, the KYRO, the n@omi and n@omi2 arcade boards.



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Great stuff - thanks !