[SDL] garbage in 'unused bits'

Pete Shinners pete at shinners.org
Thu Jul 11 00:36:00 PDT 2002


i'm finding some blits in SDL will 'fiddle' the unused bits in a 32bit 
surface. i suppose this is not too strange, but i'm finding it's making 
things a little trickier to get colorkeys correct. (since the colorkey 
compares these unused bits)

i guess i'm not too surprised that these unused bits are "undefined" but i 
was sort of hoping they would remain masked out during blits?

the case where i'm seeing this is blitting an image with surface alpha onto 
a 32bit RGB (no A) surface. it may happen with other cases too, but this is 
where it's come up for me.

i'm wondering what the status of this is. is this something that 
could/should be fixed in a later SDL release? or should i accept that these 
bits are undefined.




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