Hi all,
is it we can't move sprites smoothly from screen top?
sprites should be shown with y position starting from zero and
whole sprite will be hidden with y position between 240 and 255?
Any tricks to achieve this?
Best Regards,
Blanc
It depends on your TV. I think almost all NTSC TVs will cut off the first 8 lines, and some of them cut off even more. I'm not sure about PAL screens.
You could enable background and sprite drawing only from scanline 8 on... Leave both disabled and have a mapper generate an IRQ at scanline 8, and in the IRQ routine you enable both. You could also use some timed code...
This way you can make sure your sprite will not "magically" appear, but you'll get an 8 pixel border at the top of the screen, muck like the one you get when you enable clipping of the 8 leftmost pixels of the screen.
If you clip the top and the left you could have your sprites enter the screen smoothly. Although, like Memblers said, it really isn't visible on an actual TV, you might just want to be safe.
Niиtendo did not disqualify games if sprites popped into view at the top of the screen. Play Super Mario Bros. 3 with an emulator set to show all 240 lines showing and then have Luigi approach the top of the screen (especially in world 3-9, where I first noticed it years ago).
Yeah, many licenced PAL games has horrible BG giches, especially in the Megagman series and Double Dragon 1/2, but they're still licenced. I don't own Mario 3, but if there is gliches in NTSC mode, it would be worse in PAL mode scince the first and the last 8 rows aren't hidden.