05-14-2003, 06:26 AM
kofman, I don't know if you missed my post 
With those "AND 63" you are limiting to 6 bits, and that's _exactly_ what your VGA does. It will only read the 6 less significant bits, so doing AND 63 and not doing it is just the same.
Instead, you should divide by four, as I pointed out.
Also, as I explained, PALETTE is slower than the OUTs, 'cause it waits for a vsync (in most VGAs), so it means that you'll only be able to change a DAC register each 1/60 of a second.
To achieve transparency, you just make your blitter skip a certain colour. Most libs skip 0 'cause it is the fastest way (just an assembly jump). If you are gonna use GET/PUT, you'll need some masking. Masking is a technique which needs a mask for each sprite. I posted an extensive explanation on the technique before the forum hack - if you need it, I'll do it again, but it is not a good technique 'cause it is slow and needs as twice as memory as the transparency skipping technique.
The bad thing about the transparency skipping technique is that it is damn slow in pure QB, and you'll better use a LIB with a good transparent sprite blitter, or code it in assembly or C.
"Backdrops" are just the background graphics. Blame Capcom if I use that semi-inaccurate word
With those "AND 63" you are limiting to 6 bits, and that's _exactly_ what your VGA does. It will only read the 6 less significant bits, so doing AND 63 and not doing it is just the same.
Instead, you should divide by four, as I pointed out.
Also, as I explained, PALETTE is slower than the OUTs, 'cause it waits for a vsync (in most VGAs), so it means that you'll only be able to change a DAC register each 1/60 of a second.
To achieve transparency, you just make your blitter skip a certain colour. Most libs skip 0 'cause it is the fastest way (just an assembly jump). If you are gonna use GET/PUT, you'll need some masking. Masking is a technique which needs a mask for each sprite. I posted an extensive explanation on the technique before the forum hack - if you need it, I'll do it again, but it is not a good technique 'cause it is slow and needs as twice as memory as the transparency skipping technique.
The bad thing about the transparency skipping technique is that it is damn slow in pure QB, and you'll better use a LIB with a good transparent sprite blitter, or code it in assembly or C.
"Backdrops" are just the background graphics. Blame Capcom if I use that semi-inaccurate word
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