Spectrum Computing

Can you tell what is what? I suppose no. Now imagine that you have such tiles and have to build a level with them in some level map editor. It's a nightmare.

Joefish wrote: ↑Thu Dec 07, 2017 11:18 pm Well, the trick is to set yourself some strict rules for level design to reduce the number of potential combinations. The easiest is to always leave one whole empty tile between different objects, then each object is only ever paired up with empty space.

But yes, it means a simple platform block becomes three separate tiles; empty space->platform, platform->repeated platform, platform->empty space.

I think there's other way as well. I mean, to mark the places of the current frame where proper scrolling is required and other places where a copy of the neighbouring (just scrolled) tile could be push'ed fast. Do not bother with combinations and wasting memory on pre-shifted tiles. Speed is determined mainly by the least percentage of empty space of all the possible frames. It is also possible to dynamically generate the scroller code making it faster. All in all, i think a screen similar to Stormlord's may be scrolled in 50fps with one-pixel precision.

Ralf wrote: ↑Sun Jan 05, 2020 3:29 pmIf you feel that it's doable then please do it We all would like to see something like that.

Ralf wrote: ↑Sun Jan 05, 2020 3:29 pmThe closest existing thing I know is this demo, It is one pixel precise and running at 50 Hz indeed.
https://spectrumcomputing.co.uk/index.p ... 6&id=30420

But it's more similar to Cobra and not Stormlord as it has very limited graphics.
And adding sprites to it would probable slow it down and spoil all the effect.

https://zx-pk.ru/threads/11233-sea-drag ... post344002

Ralf wrote: ↑Sun Jan 05, 2020 4:21 pm But would it work with graphics like Stormlord? Or Zynaps? Or Robocop?

But typical Stormlord screen usually has much more empty space to skip

Ralf wrote: ↑Sun Jan 05, 2020 6:22 pm Maybe you missed it from the earlier discussion but Stormlord actually skips empty space.

Ralf wrote: ↑Sun Jan 05, 2020 6:22 pm It works more or less the same way that you are talking about, I believe. Tiles are stored with some empty space at the edges
and when game area scrolls new tiles clear everything behind them.

Seven.FFF wrote: ↑Thu Dec 07, 2017 8:19 pm This is things in the foreground moving horizontally, rather than the entire background - but you can get pretty fast and furious, and deal with different speeds, when you scroll preshifted stuff. As long as you have the space to store all the different versions. I've gone 128K-only here for that reason!

wizbob wrote: ↑Tue Sep 01, 2020 12:47 pm I don't know if you guys have seen this beautifully illustrated review of the dixel scrolling in Ghosts'n'Goblins.

C.Born wrote: ↑Sat Dec 09, 2017 5:28 pm

Code: Select all

; your sinclair issue 19 page 74
; it stll needs a full loop

org 32000
        di
        ld bc,6144
        ld hl,22527
loop:   srl (hl)
        call c,sub1
        srl (hl)
        call c,sub2
        dec hl
        dec bc
        ld a,b
        or c
        jr nz,loop
        ei
        ret
sub1    inc hl
        set 6,(hl)
        dec hl
        ret
sub2    inc hl
        set 7,(hl)
        dec hl
        ret

    ld hl,16384
    ld bc,24
loop:
    rr (hl)
    ex af,af'
    rr (hl)
    ex af,af'
    inc l
    djnz loop
    inc h
    dec c
    jp nz,loop

    ld hl,16384
    ld b,192
loop:
REPT 31
    rr (hl)
    ex af,af'
    rr (hl)
    ex af,af'
    inc l
ENDR
    rr (hl)
    ex af,af'
    rr (hl)
    ex af,af'
    inc hl
    dec b
    jp nz,loop

Einar Saukas wrote: ↑Tue Sep 01, 2020 6:53 pm Here's my version of dixel scrolling:

Code: Select all

    ld hl,16384
    ld bc,24
loop:
    rr (hl)
    ex af,af'
    rr (hl)
    ex af,af'
    inc l
    djnz loop
    inc h
    dec c
    jp nz,loop

The same routine using unrolled loop:

Code: Select all

    ld hl,16384
    ld b,192
loop:
REPT 31
    rr (hl)
    ex af,af'
    rr (hl)
    ex af,af'
    inc l
ENDR
    rr (hl)
    ex af,af'
    rr (hl)
    ex af,af'
    inc hl
    dec b
    jp nz,loop

Nienn Heskil wrote: ↑Tue Oct 06, 2020 4:53 pm For 2px scrolling, try POP: RL: RL: PUSH. I have one such routine that scrolls some 30x192 area, the resulting speed is about 31T/byte (uncontended), which is close to RL (HL) x2 with nothing in between.

catmeows wrote: ↑Tue Oct 06, 2020 6:05 pm

Nienn Heskil wrote: ↑Tue Oct 06, 2020 4:53 pm For 2px scrolling, try POP: RL: RL: PUSH. I have one such routine that scrolls some 30x192 area, the resulting speed is about 31T/byte (uncontended), which is close to RL (HL) x2 with nothing in between.

I don't see how this could work. Could you share your code ?