Vampire Killer

Enlighted (4156)

24-12-2022, 18:34

on a pc xt tandy https://www.youtube.com/watch?v=9kq_6wSUmrA&t=1203s
Someone think a msx2 version could do a little better in terms of scrolling using the VDP?

By sd_snatcher

Prophet (3675)

25-12-2022, 15:46

You mean, like these? Seems to already have been proven many times...

Green Beret SC5 scroll MSX2
1 pixel MSX2 scroll demo with colored border for performance assessment
And even with 256 simultaneous colors:
MSX2 SC8(256 color mode) horizontal scroll, 90% free CPU

By PingPong

Enlighted (4156)

25-12-2022, 17:04

sd_snatcher wrote:

You mean, like these? Seems to already have been proven many times...

Green Beret SC5 scroll MSX2
1 pixel MSX2 scroll demo with colored border for performance assessment
And even with 256 simultaneous colors:
MSX2 SC8(256 color mode) horizontal scroll, 90% free CPU

No, i mean a more classical approach of brute force scrolling. In the video i've measured a 3 fps. The vdp should be able to do a little better.

By gdx

Enlighted (6442)

26-12-2022, 01:22

The VDP copy command is too slow to do this. We are forced to use the "SET ADJUST" to make a clean scroll.

By syn

Prophet (2135)

26-12-2022, 01:56

PingPong wrote:

No, i mean a more classical approach of brute force scrolling. In the video i've measured a 3 fps. The vdp should be able to do a little better.

You mean something like Ys3?

By sd_snatcher

Prophet (3675)

26-12-2022, 02:48

I wonder why impose this requirement to scroll using the blitter, since it's more resource intensive and less efficient than a smooth scroll using the screen offset register (just like it's done on the C64, amongst others).

By PingPong

Enlighted (4156)

26-12-2022, 10:07

gdx wrote:

The VDP copy command is too slow to do this. We are forced to use the "SET ADJUST" to make a clean scroll.

The vdp hmmc copy command can do 6-7 fps for a full screen scroll. The game as little less game area.
Judging by the tandy video the fps on pc are less than 6 fps

By gdx

Enlighted (6442)

26-12-2022, 12:07

That's what I'm saying, it's too slow. Look at the Ys series, it's not full screen but it's already too slow.

By Metalion

Paragon (1628)

26-12-2022, 13:03

PingPong wrote:

on a pc xt tandy https://www.youtube.com/watch?v=9kq_6wSUmrA&t=1203s
Someone think a msx2 version could do a little better in terms of scrolling using the VDP?

Well of course, that's a simple 8 pixels character scroll.
Could be done simply on SCREEN4, and much more rapidly than on this Tandy machine.

PS: The test of Castlevania is rather at 1071s than 1203s.

By PingPong

Enlighted (4156)

26-12-2022, 15:01

gdx wrote:

That's what I'm saying, it's too slow. Look at the Ys series, it's not full screen but it's already too slow.

i know the vdp is slow. but my question is another. can we get better performances even using the brute force scrolling approach on VDP with HMMM commands?
I've never measured tandy fps but i think we can get a bit more. Even if we considering what we have hw sprites and we are not not necessarily forced to move the entire screen

By PingPong

Enlighted (4156)

26-12-2022, 15:02

Screen 4 is not the point, I mean screen 5. Since i talked about VDP commands