Line lengths.

[Lando]

SoLo2 wrote:

  Hello!

  I am new to the Amiga World!
  Testing a little assembler I
  got to this code, that sets the
  screen I will be using.
  So, it seems like it _must_ be
  reinitialized at each screen refresh,
  true?
  That means that it can be initialized
  in the copper list, or otherwise in a
  separate routine,
  that writes directly to the registers.

Welcome to amiga.org!

Of course the hw registers don't _have_ to be reinitialised at each refresh - you can set them just once and they will stay that way until you change them.

It's just handy to have them in the copperlist.

  The problem arises when changing
  the "diwstrt" and "diwstop" registers.
  If I try using horizontal (x) start and
  end coordinates that are more to the
  left, for example $xx51 and $xx91,
  (this would start,stop at 079,145+256)
  then the effective visible line shrinks
  from 320 down to 272. The virtual line
  seems to remain the correct 320, but
  you   see   I set the modulo registers
  ($0108, $010a) to zero, to not have a
  bigger, virtual line...

  Why? who knows?

 
CopperList
  dc.w    $0100,$1200 ;bplcon0 set 1 plane, color
  dc.w    $0108,$0000 ;bpl1mod offset to next line
  dc.w    $010a,$0000 ;bpl2mod offset to next line
  dc.w    $008e,$3081 ;diwstrt start coords 048,129
  dc.w    $0090,$30c1 ;diwstop stop coords  304,449
  ; 320 (normal) visible line width
  dc.w    $0092,$0038 ;ddfstrt L margin normal (horz)
  dc.w    $0094,$00d0 ;ddfstop R margin normal (horz)
  ; to point to bitplane 1
  dc.w    $00e0       ;bitplane0 hi
hi0
  dc.w    $0000
  dc.w    $00e2       ;bitplane1 lo
lo0
  dc.w    $0000
  dc.w    $0182,$0ff0 ;color01



  I am using excellent UAE-0.8.21
  emulator under Linux. Great!

  SoLo2

I really have no clue.  Why are you messing with diwstrt and diwstop anyway?  I never understood them and didn't really try to - just found values that worked and used those same values for ever - dc.w $8e,$2c81,$90,$2cc1 - centred for every (Pal) TV or monitor I tried.

Just thinking about this makes me remember how much fun Amiga coding used to be.  I suddenly want to buy another A1200 and write a parallax starfield with a sine-scroller and glenz-vectors.

I never had anywhere near so much fun coding on XBox, GC, PS2, or DC. (PS1 was cool to code on also.)

[Lando]

Hyperspeed wrote:
I doubt there was much on the Net Yaroze that the CD32/SX32 couldn't manage.

We neglect our hidden heritage!

The PlayStation 1 was way more powerful even than a CD32/SX32 Combo.  The CD32 lacked 3D hardware (Akiko doesn't really count).  Something like Ridge Racer Type 4 or Resident Evil 3 still couldn't be done to the PS1 standard on a 060 equipped A4000 without at least a 3D card. The minimum spec for the conversion of Wipeout 2097 (the only PS1 conversion I know of for the Amiga) was a PowerPC accellerator and 3D graphics card   and even then the framerate wasn't as high as the PS1.

I never actually used a Yaroze when I first started PS1 programming - I started on a standard chipped grey PS1 connected to a PC via an Action replay cartridge and a parallel cable.

lou_dias wrote:

Lando wrote:

I never had anywhere near so much fun coding on XBox, GC, PS2, or DC. (PS1 was cool to code on also.)

You used to code for consoles?  Professionally or homebrew?

First homebrew, then professionally over 5 years.  I worked on about 6 published games for the major consoles.  Homebrew is more fun - there is so much pressure when you're working to deadlines and a 7-days a week, 16 hours a day schedule when you're nearing the end of a project or coming up to a big show like E3 where you have to show a demo.  But still nothing beats walking into a game store and seeing the end result on the shelf.