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Re: HGR inside DHGR



Bryan Parkoff wrote:
"mdj" <mdj.mdj@gmail.com> wrote in message 1152165129.037877.28290@v61g2000cwv.googlegroups.com">news:1152165129.037877.28290@v61g2000cwv.googlegroups.com...

BLuRry wrote:

B,

  Sorry.  My response was too harsh.   I do want to understand what
you are trying to say, but am often just not able to.   I will keep
trying.

If it makes either of you feel better, I speak 6502 better than I can
speak English.  Much easier language, in my opinion.

I agree it would be handy, when facing a difficult situation to simply
perform an absolute indirect indexed jump rather than deal with all
that 'diplomacy' gibberish ;-)

Btw Bryan, it seems logical that LORES maps 100% perfectly to DHR, as
the colours are identical, the artifacting would also be the same, but
it's nice to confirm that it does indeed come out that way. Do remember
that there is a double lores mode as well - if you write a program that
uses double lores page 2, you'll have done something not many have :-)

What exactly is your goal? Are you trying to determine an 'ideal'
mapping of Apple II graphics onto a higher resolution display?

Matt


Matt,

Yes, it is what I meant. NTSC pixels run at 14MHz still use artifact colors. It is not a problem as long. You can still write LORES in both 40/80 columns into DHGR. HGR can be done in DHGR, too. I have written a program to convert each HGR byte to two bytes. It is the way how each HGR byte is like 80 column in 40 column as 14MHz so it is converted to 7MHz in 80 column. Then 7 MHz is splited into two bytes. Two bytes are 14MHz from splited 7 MHz. Each left byte go in bank 1 and each right byte go in bank 0. Both Bank 0/1 display both bytes to show emulated HGR in DHGR. One problem is with color mapping, but pixel structure is 100% perfect. For example, in DHGR, HCOLOR=1 is orange, HCOLOR=2 is blue, HCOLOR=5 is green, and HCOLOR=6 is violet. You may be surprised to claim that HCOLOR is wrong. Well, it is opposite color because color mapping in both 40/80 column are not the same. 40 Column color mapping has to be rotated in the right to match 80 column color mapping. I have unanswered question why 40/80 column color mapping are different. You can still be able to draw mixed LORES 40/80 and HIRES 40 into DHGR. It looks great. Think about Money Munchers how Bob Bishop designed to use $C050/$C051 switches, but it is not needed because DHGR is activated. No annoying with flicker back and forth.

But the *appearance* of a screen is only one attribute.  Another that
is *very* important if the screen is being animated is the number of
bytes that must be changed to create the next frame.

This is why lo-res and text animation is attractive, even with its
limitations.  It would be many times slower to animate a lo-res pattern
displayed in DHR.

-michael

Parallel computing for 8-bit Apple II's!
Home page:  http://members.aol.com/MJMahon/

"The wastebasket is our most important design
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