Re: A85: Sliding Pixels
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Re: A85: Sliding Pixels
i am getting confused a bit.
to scroll a sprite up one bit, in my understnading:
1) Original configuration. backgound under the sprite is saved, using
PSPG_CLP
.............
...10011011.. notice some of my sprite is using masking
...111...1...
...1000.0.1..
...0111..00..
...11000100..
.............
2) restore background using PSPR_NR
.............
.............
.............
.............
.............
.............
.............
3) redraw sprite 1 pixel upwards using PSPG_CLP again to save the background
...10011011..
...111...1...
...1000.0.1..
...0111..00..
...11000100..
.............
.............
This is the way i understand it anyway. these functions are usgard
functions. i think source is on ticalc if you wanna use zshell or
something. the PSPG_CLP does clipping, saves background, and does masking.
but masking and saving the backgournd do not need to be both present. it
just so happens that that function has them both.
I may have misunderstood you, Humberto, and if so, i am sorry. this is how
i understand it.
Jonathan Kaus
kaus@cybrzn.com
At 08:07 PM 10/6/98 -0700, you wrote:
>
>On Tue, 6 Oct 1998 PXGray@aol.com wrote:
>> In a message dated 10/6/98 1:22:24 PM US Eastern Standard Time,
>> humberto@engr.csufresno.edu writes:
>>
>> > It depends on the size of your sprites (when you slide from left to right
>> > or vice versa) If your sprites are 8 pixels wide then you draw over the
>> > sprite (only up 1 pixel) then if you have a background, draw the
>> > background where the bottom of the sprite used to be. This way you
don't
>> > use the graph mem and you have smooth scrolling.
>> > Here's a picture if I made no sense..
>> >
>> > $FC00 ................ -> ..10001001....
>> > $FC10 ..10001001...... -> ..10000001....
>> > $FC20 ..10000001...... -> ..,,,,,,,,.... <-Uncovered BG
>> > $FC30 ................ -> ..............
>> >
>> > If you're using a sprite routine that supports masking it makes using
>> > backgrounds a lot easier. In that case you would just draw you sprite
>> > shifted up 1 then redraw the background that was uncovered.
>> >
>> > -Humberto Yeverino Jr.
>>
>> This makes absolutely no sense. Can anyone explain it in a simpler form of
>> the english language?
>>
>Sure, but I need a question that isn't as vague as "sliding sprites". Is
>there a background? Is it a tile based game? Vague answers for vague
>questions...
>
>-Humberto Yeverino Jr.
>
>"I kick ass for the Lord."
>-Dead Alive (1992)
>
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