Re: A83: Re: Most-wanted answers...


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Re: A83: Re: Most-wanted answers...




On 09-Aug-98, Hannes Edfeldt wrote:

>> I really don't think Pat can answer that... sprites (which is a bad name,
>> because it implies that it's some kind of hardware magic... hi Movax...) 

>No, not at all. You got all that mixed up, are you an amiga user or
something?

Yep, ofcourse.

>Anyway, the word "sprite" has nothing to do with hardware nowadays (if it
ever
>had). I've found a quite good definition for it; "Sprites are special pieces
>of 
>graphics which can be manipulated independently from the rest of the screen".


Yes it "ever had". The c64 was the first computer with hardware sprites,
right? Looking in the c64 programmer's ref, it says "MOB" (movable object?),
but for some reason people started calling it sprites instead. When the Amiga
came, the same phenomenon was documented as "sprites". In both cases, it was
(is) a way of defining 16-pixel-wide any-height pieces of graphics that could
be placed anywhere on the screen, without ever disturbing the underlying
bitmap. The Amiga still uses a sprite for the mouse pointer, and according to
me that's really the only acceptable way of implementing a pointer.

>So, a sprite is just a block of graphics that can be moved around without 
>interfering with the background.

Right.

> It doesn't have to be done with "some kind
>of hardware magic".

Wrong. See the difference? Your routines modify the bitmap, sprites don't
because they're handled automatically by the video chip when it's sending data
to the physical screen. In Amiga terms, your "sprites" would be called bobs
(blitter objects, allright there's no blitter involved here, but bobs are
objects that are drawn to the background bitmap and later removed) but NOT
sprites.

> And I'm aware of the fact that those routines I've
>released
>won't restore the background. I'd still call them sprite routines though =)

>-- 
>Hannes Edfeldt * movax@algonet.se

Yeah, it's your routines, you can call them whatever you like. But you're
still wrong. =)

Linus


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