Scrolling attribute thing

FrankT

Just messing with scrolling attributes. Its absolutely no use, but impressed with the variable speeds of scrolling.

https://dl.dropboxusercontent.com/u/9498358/attrscroll.tap

I'll try and display text instead of a testcard pattern. A big 'Game Over' message or something...

Zetr0

Thats pretty impressive Frank!

BloodBaz

I love attribute scrolling. It can be fast and when interrupt aligned, very smooth.

g0blinish

what was that?OooO

mcleod_ideafix

This makes me question... is there any (decent) game that uses attribute only based graphics?

Hikaru

mcleod_ideafix wrote: »

This makes me question... is there any (decent) game that uses attribute only based graphics?

E.g. splATTR

Ivanzx

Hikaru wrote: »

E.g. splATTR

Amazing game BTW, one of the best from the non-commercial era of the Spectrum

Also, but I may be mistaken, LumASCII could be similar:

http://www.worldofspectrum.org/infoseekid.cgi?id=0027965

Metalbrain

There's also Alien 99, but it's a much simpler game.

daveysludge

How about jetmobile from cassette 50?

slenkar

what about extreme, the chewits game, karnov they look like attribute only games

EDIT - oh no dots just squares...

FrankT

I made that last night after a few beers and whisky's.

This one is interesting. If you tilt your head sideways, it looks like the blue, red, magenta are stationary and only the white, yellow, cyan and green are moving.

Trying to control it. Just about got it moving up and down at the same speed. Its not in sync with the interrupt at all. Just pushing 2 fullscreen attribute patterns to the screen. The height of the colour blocks is how long it takes before it starts drawing the second attribute screen.

https://dl.dropboxusercontent.com/u/9498358/attrscroll2.tap

BiNMaN

how would it look side to side? I appreciate there would be more maths involved

Paradigm Shifter

Try tilting your head 90 degrees...

BiNMaN

Paradigm Shifter wrote: »

Try tilting your head 90 degrees...

nah it'd be easier to rotate my laptop

SKR

Just a quickie pretty please.......

Can anyone tell me a quick way to do HL=HL+8*A

I used to know this, but the brain is fogged with old age :(

Thanks in advance.

(Didn't think it was worth making a new thread, sorry for interrupting, and it is (kinda) related)

Paradigm Shifter

Shift A left 3 times (needs to be < 32 though). Then you need to copy it into E I think (with D = 0) and do add hl, de? If A is >= 32 you need to propagate the carry from each shift into D (and shift that left every time you shift A left as well).

SKR

Paradigm Shifter wrote: »

Shift A left 3 times (needs to be < 32 though). Then you need to copy it into E I think (with D = 0) and do add hl, de? If A is >= 32 you need to propagate the carry from each shift into D (and shift that left every time you shift A left as well).

Thanks, yeah A will invariably be >=32 so the 2nd solution is boss

Thank you very much :)

Paradigm Shifter

Or you could ld bc, hl; clear hl, ld de with a, add hl, de (3 times, so hl = a * 8 - stoopid smileys) and then ld de, bc and add hl, de. Dunno which would be faster... but there's no messing with the carry flag or shifting d involved with that method.

Hikaru

For a more straightforward approach,

ld e,a
	ld d,0
	ex de,hl
	add hl,hl
	add hl,hl
	add hl,hl
	add hl,de

SKR

Paradigm Shifter wrote: »

Or you could ld bc, hl; clear hl, ld de with a, add hl, de (3 times, so hl = a * 8) and then ld de, bc and add hl, de. Dunno which would be faster...

Cheers :)

Speed isn't much of an issue as it's only for an attribute text scroller which isn't very critical.

Years ago I would have written it in 10 mins, but after so long away from coding, I just couldn't get my head around it.

Anyway, it's working now, thanks a million for that :)

Paradigm Shifter

My 2nd method was wrong anyway (need to add hl, hl 3 times not add hl, de). The guy who posted after me had an even better way.

EDIT: The shift left 3 times method is only really best if A < 32.

SKR

Hikaru wrote: »

For a more straightforward approach,

ld e,a
	ld d,0
	ex de,hl
	add hl,hl
	add hl,hl
	add hl,hl
	add hl,de

Just tried this, excellent :) Thank you very much