SDL_SetAlpha bug

I’ve got some simple code trying to do a ‘fade from white’ by
blitting an all white image with progressively lower alpha values.

the code as attached works fine, but if you change the starting
alpha level to 255 (instead of the current 254) you’ll find that
changing the alphas doesn’t have any effect.

in fact, it seems once any image has had it’s alpha set to 255
there is no way to set the alpha to any other value. the alpha
values inside the SDL_Surface are being updated correctly, but
the blit is still treating it as 255.

is this a bug on my end? a feature? or some brilliant display
of short-sightedness on my end :]

thanks guys

begin 666 alpha.c
M(VEN8VQU9&4B4T1,+F at B#0H-"@T*:6YT(&UA:6XH0T>PT*“6EN=”!A;’!H
M83L-"@E31$Q?4W5R9F%C92 J<V-R965N+" J9F%D97([#0H)4T1,7U)E8W0@
M:&%L9B ](‘LP+" P+" T,# L(#(P,‘T[#0H-"@E31$Q?26YI=“A31$Q?24Y)
M5%]6241%3WQ31$Q?24Y)5%]424U%4BD[#0H-@ES8W)E96X@/2!31$Q?4V5T
M5FED96]-;V1E*#0P,“P at -# P+” P+" P3L-"@EF861E<B ](%-$3%]#<F5A
M=&521T)3=7)F86-E
# L(#0P,“P at -# P+” S,BP@,‘AF9C P,# L(#!X9F8P
M,“P@,'AF9BP@,“D[#0H)4T1,7T9I;&Q296-T*&9A9&5R+”!.54Q,+” P>&9F
M9F9F9BD[#0H)4T1,7T9L:7 H<V-R965N3L-"@T#0H)9F]R*&%L<&AA(#T@
M,C4T.R!A;’!H82 ^/3 (&%L<&AA("T4T1,7T9I;&Q2
M96-T*’-C<F5E;BP at 3E5,3"P@,"D[#0H)"5-$3%]&:6QL4F5C="AS8W)E96XL
M(“9H86QF+” P>&9F3L-"@T"0E31$Q?4V5T06QP:&$H9F%D97(L(%-$3%]3
M4D-!3%!(02P at 86QP:&$I.PT*"0E31$Q?0FQI=%-U<F9A8V4H9F%D97(L($Y5
M3$PL(’-C<F5E;BP at 3E5,3"D[#0H-"@D)4T1,7T9L:7 H<V-R965N3L-"@D)
M4T1,7T1E;&%Y
#4P3L-"@E]#0H-"@E31$Q?1&5L87DH.# P3L-"@T*“5-$
M3%]&<F5E4W5R9F%C92AF861E<BD[#0H)4T1,7U%U:70H*3L-”@ER971U<FX@
%,3L-"GT
end