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Coding > Sonic's Spotlights

#13819 - jasonbb - Tue Dec 23, 2003 12:08 pm

I have a question regarding the GBA game "Sonic The Hedgehog".
The 3rd level shows two scanning spotlights illuminating the game graphics. The game intro animation also has this effect.
Does anyone know how to create this spotlight effect?
Cheers.

#13821 - torne - Tue Dec 23, 2003 12:42 pm

They probably use the windowing effect (done in hardware) but changing the window registers on HSYNC to get non-rectangular windows.

#13824 - jasonbb - Tue Dec 23, 2003 2:24 pm

Thanks torne,
I know how to use HSYNC but I can't find anything on Windowing.
Could you direct me to some code or a tutorial.

#13834 - tepples - Tue Dec 23, 2003 5:05 pm

I don't know of any such tutorials, but you might be able to get something out of the section on windowing in the CowBite spec.
_________________
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#13924 - headspin - Thu Dec 25, 2003 12:36 am

This questions comes up quite alot and generally I direct people over to Darkcloud's examples on his website.. http://sinewave3.tripod.com/.

#13968 - johnny_north - Fri Dec 26, 2003 5:54 pm

I like this particular ref: http://www.work.de/nocash/gbatek.htm#lcdiowindowfeature

I just worked through the spotlight/window thing myself - let me know if you need more help