faulks78 / genplus-gx

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Samurai Shodown (PAL) pixel garbage? #193

Closed GoogleCodeExporter closed 9 years ago

GoogleCodeExporter commented 9 years ago
Hi there,

i just got a copy of Samurai Shodown for my megadrive where i get some pixel 
garbage lines on the screen (in character select + ingame). it doesn't happen 
in any emulator (like genplus gx ;)) so i'm asking if my cartdige is damaged or 
does this happen for others as well on real machine? tried it on both my 
Megadrive 1 and 2. Happens with RGB as well as with a RF unit. i attached a 
video showing the pixel garbage.

http://www.megaupload.com/?d=2N1L6ZJ0

Original issue reported on code.google.com by gora.pat...@gmail.com on 29 Oct 2011 at 3:30

GoogleCodeExporter commented 9 years ago
I see nothing wrong. Garbage pixels are generally artefacts of Color RAM writes 
during active display. In this case, written color value interferes with the 
value read by the VDP when rendering current pixel.

This is generally not emulated because exact behavior is still not fully 
understood. I think only Retrocopy has some attempts to emulate it but it's not 
100% accurate and much more noticeable that with real hardware. Anyway, most 
games don't do this and change color palettes during hblank or vblank.

Original comment by ekeeke31@gmail.com on 29 Oct 2011 at 5:57

GoogleCodeExporter commented 9 years ago
Ah ok. thank for the explanation. i was just wondering, because it's so visible 
in the center of the screen. and not somewhere off the picture.

Original comment by gora.pat...@gmail.com on 30 Oct 2011 at 1:05