>I checked your overscan-proggie and it indeed looks very, very nice.
Thanks -_-v Please come back for more.
>> NB: The display adjustment trick DOES NOT WORK since display start is only
>> checked ONCE per frame by the vertical blanking circuitry. You can only
>> alter horizontal adjustment on the fly (the register is checked every
>> raster line).
>
>Fortunately, 'cause otherwise my nice 4-direction smooth scroll (which still
>isn't perfect!) wouldn't have worked.
So what does prevent it from being perfect?
>> I've noticed rare sprite behavior when using graphics 7 (SCREEN 8) mode 2
>> sprites.
>>
>> 1) It's impossible to obtain opaque black (color code 0000 + active pixel
>> on the pattern).
>
>True. You'll have to (re)set bit 5 in VDP r#8 (something like "Transparant
>mode enable").
It works! Thanks 8:D
>> 2) "Bright" black (color code 1000) yields *ORANGE* (!!!).
>
>Color code 1000??? What do you mean with 1000??? Is it an RGB-code (which
>should then be 3-digit, not 4-digit), or is is a binary number (then state %
>or &b in front of it)???
>If it's binary then it's color code 8, and if I do COLOR 15,8 in Basic I get
>a red background.
It's a 4-bit digital RGBI sprite color. To be precise, it's an IGRB color
code (Intensity Green Red Blue) that works in gfx7. In other modes it's
just a 4-bit index for the 16 color palette.
1000 should be an "intensity enabled" black, but yields pure orange on a MSX2.
>> Attached is a tiny test. It shows 2 horizontal orange blocks when in
>theory
>> it should be a solid opaque black square with two "bright" black strips.
>> I've tested it only on 9938 VDPs.
>>
>> I'd appreciate if someone could test the program on later VDPs so I could
>> make the assumption it works this way on all MSX models.
>
>On my v9938 VDP I saw a bright 2x2 green dot.
>On my v9958 too.
Oh yes. And if you wiggle your joystick in port 1 you should be able to
paint the screen with a smooth overscan scroll!!!
But what *around* that green dot? black or orange stripes? or nothing???
>By the way, this file only worked in Dos1-environment... Why??? Are you
>changing the memory or so??? Also (and that also goes for the
>overscan-demo), your programs reset afterwards... is it so difficult to
>execute a BIOS-call to select screen 0 again and the terminate the
>Dos-program (JP 0 or LD C,0:CALL 5)???
I just can test my programs in MSX2 computers running DOS1. They work 100%
in those environments. I abuse the memory since it's just a quick and dirty
test. I don't check for system memory boundaries yet -neither drive spin
down-, sorry.
The program indeed reselects screen 0 by using a BIOS call, but DOS2 memory
is likely to be seriously trashed at this point.
Hope to fix it in forthcoming tests. Watch out.
>Errm... Something completely different... I checked the Yamaha-site, and at
>the videoprocessor-part I read the following:
>
>Product: V9938
>Display Type: CRT
>Display Format: Up to 512x424
>Grayscale & Colors: Up to 512
>Output: Linear RGB & Composite Video
>
>Up to 512 colors???
>How did they think to do that??? I hope not using screensplits...
It means a 512 color palette (9-bit RGB).
>And about the greyscale-bit... if I set the bit in one of the VDP's
>control-registers (0, 1, 8, 9) my screen does everything but turn grey.
Dunno. Will test/investigate as well.
Kiss you lot.
--
Madonna Mark Two
"Martin Galway means to me what Elvis meant to Sigue Sigue Sputnik"
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