Re: A89: GrayScale and Program Ideas
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Re: A89: GrayScale and Program Ideas
thanks.. is there a working grayscale sprite routine somewhere? Dux's
doesn't quite work...
Ahmed El-Helw <ahmed@ticalc.org>
Program Ideas and Upcoming Programs
the ticalc.org project - http://www.ticalc.org/
_______________________________________
http://hail.icestorm.com/asm/
ICQ: 3350394
----- Original Message -----
From: Matt Johnson <matt2000@dogtech.com>
To: <assembly-89@lists.ticalc.org>
Sent: Thursday, December 31, 1998 6:53 PM
Subject: Re: A89: GrayScale and Program Ideas
>
>That is the theory, but not the practice. In reality, you have two seperate
>sprites, each which are blitted to two different sections of video memory.
>The interrupt routine will change the pointer to the screen displayed
>
>.. At least this was how it was done on the TI-86. I'm sure it is done the
>same way for the TI-89, for the simple fact that decoding a 2-bit/pixel
>sprite would be a lot slower then having two seperate sprites which, when
>two sepearate video memories are rapidly cycled at the speed from which the
>ISR is called, it will look like a 4 color screen.
>
>Ugh! I know that is a bad explanation, I have a much more detailed
>explanation for grayscale in 86 central (http://www.acz.org). The same
>concepts, I'm pretty sure, are for the TI-89 also.
>
>>>Grayscales sprites simply have more bits defining the shade of each
>>pixel. In the 1-bit system commonly employed, a 0 is completely white
>>and a 1 is completely black. In a system using multiple-bits per pixel,
>>00... is still white and a 11... is still black, but other values offer
>>differing shades of gray. If you wish to use two bits per pixel, 00
>>would be white, 01 would be light gray, 10 would be dark gray, and 11
>>would be black. This concept continues through an infinite rang of
>>possible bits-per-pixel.
>>
>>On Thu, 31 Dec 1998 12:20:10 -0500 "Ahmed El-Helw" <ahmed@ticalc.org>
>>writes:
>>>
>>>Hello,
>>> I had a question - how exactly do grayscale sprites work [how are
>>>they
>>>made data wise].. like a normal sprite is simply .db %00010101 on the
>>>z80..
>>>how do you do a normal and grayscale sprite on 68k?
>>>
>>> As for the program ideas -- i know I should put this on
>>>ticalc.org, but
>>>I have to finish alphabetisizing them first :P Yet someone should
>>>port
>>>Plane Jump and Diamonds to the 89 :) And we need high score added to
>>>BoulderDash :) As for SameGame, I still like Jimmy's better :) Maybe
>>>because it's full screen and bigger blocks? Any thoughts? With all
>>>due
>>>respect to the author - you make awesome games.. just my 2 cents worth
>>>about
>>>SameGame.
>>>
>>>Ahmed El-Helw <ahmed@ticalc.org>
>>> Program Ideas and Upcoming Programs
>>> the ticalc.org project - http://www.ticalc.org/
>>>_______________________________________
>>>http://hail.icestorm.com/asm/
>>>ICQ: 3350394
>>>
>>>
>>
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>
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