A89: Re: Calculator-specific Issues

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A89: Re: Calculator-specific Issues


I didn't insult anyone, I'm trying to limit the spamming and off-topicness
of this list. The only thing I insulted was multi-cap names, like AmErIcA
ONlInE.. this makes it look unprofessional  IHMO, and hurts my eyes. I'm
afraid I can't help you with any TI-89 calculator specific problems, but
with the TI-86 I can. I know quite a bit about grayscale for the TI-86, and
the Dux Gregis is familiar with TI-89 grayscale (he is working on the
tutorial as we speak for TI-89 central).

I can tell you this: How an 8x8 sprite (masked) is stored like this (or
slighty different depending on the putsprite routine)
(note: .db is Z80 talk, define byte. I'm not sure what it is for 68k. Also,
% is binary)

If the mask is 0 it means transparency, if its 1 it means draw the sprite
over the background.

If a bit is set in Layer1 and Layer 2, it is BLACK
If a bit is set in Layer1 but clear in Layer 2, it is DARK GREY
If a bit is set in Layer2 but clear in Layer 1, it is LIGHT GREY
If a bit is clear in Layer1 and Layer 2, it is WHITE

Mask:
db % 0 0 0 0 0 0 0 0
db % 0 0 0 0 0 0 0 0
db % 0 0 0 0 0 0 0 0
db % 0 0 0 0 0 0 0 0
db % 0 0 0 0 0 0 0 0
db % 0 0 0 0 0 0 0 0
db % 0 0 0 0 0 0 0 0
db % 0 0 0 0 0 0 0 0

Layer1:
db % 0 0 0 0 0 0 0 0
db % 0 0 0 0 0 0 0 0
db % 0 0 0 0 0 0 0 0
db % 0 0 0 0 0 0 0 0
db % 0 0 0 0 0 0 0 0
db % 0 0 0 0 0 0 0 0
db % 0 0 0 0 0 0 0 0
db % 0 0 0 0 0 0 0 0

Layer2:
db % 0 0 0 0 0 0 0 0
db % 0 0 0 0 0 0 0 0
db % 0 0 0 0 0 0 0 0
db % 0 0 0 0 0 0 0 0
db % 0 0 0 0 0 0 0 0
db % 0 0 0 0 0 0 0 0
db % 0 0 0 0 0 0 0 0
db % 0 0 0 0 0 0 0 0

And the equation for applying the mask to the sprite and background is
(!mask & vid) | spr
That is, NOT Mask, then AND mask to the Video Byte (background), then you OR
the Sprite to the video memory.
Transparency is that easy :)

We have a working grayscale TI-89 engine, I'll get together with him and
publish it at http://www.acz.org when I get the chance. In fact, I'm working
on a grayscale windows sprite editor as we speak (for masked 8x8 sprites..)
But please, please dont spam this list because it makes it hard to recieve
messages from the acz mailing list and... it's quite annoying! :) Also, a
lot of these questions can be resolved much easier if you take advantage of
the tools of the trade, i.e. the TI-89 emulator, and the various online
resources. The emulator is especially useful for graphics related problems,
since it's visual :)

Later,
 Matt

>(Perhaps Matt Johnson can not insult a well-meaning newbie for once and
tell
>us how to do greyscale or display registers on the screen?) Anyway, this is
>getting long, I'm getting tired, and I think my point has been made. Oh,
did I
>mention that some information on greyscale would be nice? :)