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I've been looking on the way Y's displays its status bars, as it's the only game I know in the master system that displays like a "window plane" together with multidirectional scroll.

After looking in Meka & Emulicious, and searching for info, I've understood that the last rows of the tilemap are overwriten with the tiles that would make the life bars, the letters are sprites, and that somehow, some rows are blacked (vdp off?) depending on the vertical scroll position in order to display only the narrow lifebar that needs to be displayed.

How are these rows blacked? is the VDP turned off? it's some kind of raster effect?

Is this something of relevance?

http://www.smspower.org/Development/TilemapMirroring

Mostrar likely, the only other way to produce that effect would be to set the relevant colors in the palette to black, but that would require more VDP writes and could cause show effects.

Ys (JP) depends on tilemap mirroring to draw its status bar, but the export version doesn't (and the feature/bug was fixed in later VDP revisions). In both, the bar effect is achieved by drawing taller coloured bars (as you saw), then they are masked out with black by switching to an all-black secondary name table in line interrupts, which can be done safely. The Japanese version gets away with a smaller name table due to the mirroring, which allows it a bit more space for tiles.

Another game achieving the same effect (two-way scrolling with a status bar) is Gauntlet, which achieves a vertical status bar by drawing the whole status as sprites, and then masking the moving boundary tile location by also drawing a column of black sprites over it. This is hugely wasteful of sprites given the 8 sprite horizontal limit - but then the gameplay hardly uses them.

Thanks guys!, very nice explanation!

I'll also check Gauntlet. I know it's using tilemap for displaying enemies, but it'll be interesting to see their technique for status bars

You should also take a look at this game : Sylvan Tale

On YouTube :

thanks! I'll take also a look at it!

Hmm, that's an interesting one: an alternate tilemap is used for the "windowing" for text and status, and the status bar is itself drawn into tiles (and the tilemap) to offset the scrolling, so the 16px we see of that tilemap always shows the same 16px of the status area - with a little use of sprites to reduce the drawn-in tile count. The way it animates the "window" up and down is a very nice touch, too.

On a side note, the text scrolling in the "window" is also done by drawing into the tiles, which is why it's a bit jerky - the number of tiles to update then exceeds what is possible in one frame. It also means it could fairly easily have a variable-width font in the translation, since the VRAM resources are all already there...

As I have used lately only Emulicious, I have found that Meka is still more reliable when trying to have a grasp in how raster effects are working. Moreover, I think that there's no way to change the base adress for the tilemap in emulicious, is there?

I have to say that the status bar in Sylvan Tale looks really nice!

kusfo wrote

Moreover, I think that there's no way to change the base adress for the tilemap in emulicious, is there?

I think you should try again. :)

Interested.

... so i can put an lineh interrupt handler and check if i am on first 16 lines ...

But dont understand what to do to fill on black... can some one illustrate with (c better for me, although asm could be valid) code?

An example would be great!

Line interrupts are a pain because they reload the counter before the interrupt happens, so for example you set it for 16, it fires and you set it to ff, and it fires on line 32 anyway. To blank the screen you can either turn it off, or change to a name table showing blanks. The latter gives you the option of not being purely blank.

Another example came to mind: Cool Spot (and Global Gladiators, which is the same engine) do it by redrawing the whole name table when it scrolls 8px, then turning off the screen for 8px to hide the extra lines, then having blank tiles at the bottom with sprites for status.

sverx's compo-entry might also be relevant: http://www.smspower.org/Homebrew/AngunaThePrisonDungeon-SMS - I have had that one filed under "interesting statusbar w. scroll" since then :)

That was what i have searching. Thanks hangs!!!

unfortunately that solution is very very slow, eating up a lot of CPU :|
Which means: I would no longer use it. Having the health bar vertical and made with sprites would be better (also, you would get it over-imposed onto background, which is nicer than having black backdrop as in AngunaSMS)

Author	Message
kusfo Joined: 29 Mar 2012 Posts: 886 Location: Spain	Status bars with two-way scrolling (was: Ys Vanished Omens technical question) Posted: Tue Apr 18, 2017 9:19 am
kusfo Joined: 29 Mar 2012 Posts: 886 Location: Spain	I've been looking on the way Y's displays its status bars, as it's the only game I know in the master system that displays like a "window plane" together with multidirectional scroll. After looking in Meka & Emulicious, and searching for info, I've understood that the last rows of the tilemap are overwriten with the tiles that would make the life bars, the letters are sprites, and that somehow, some rows are blacked (vdp off?) depending on the vertical scroll position in order to display only the narrow lifebar that needs to be displayed. How are these rows blacked? is the VDP turned off? it's some kind of raster effect?

KingMike Joined: 14 Oct 2008 Posts: 510	Posted: Tue Apr 18, 2017 4:38 pm
KingMike Joined: 14 Oct 2008 Posts: 510	Is this something of relevance? http://www.smspower.org/Development/TilemapMirroring

gvx32 Joined: 17 Sep 2013 Posts: 128 Location: Gravataí, RS, Brazil	Posted: Tue Apr 18, 2017 5:36 pm
	Mostrar likely, the only other way to produce that effect would be to set the relevant colors in the palette to black, but that would require more VDP writes and could cause show effects.

Maxim Site Admin Joined: 19 Oct 1999 Posts: 14740 Location: London	Posted: Tue Apr 18, 2017 9:07 pm
	Ys (JP) depends on tilemap mirroring to draw its status bar, but the export version doesn't (and the feature/bug was fixed in later VDP revisions). In both, the bar effect is achieved by drawing taller coloured bars (as you saw), then they are masked out with black by switching to an all-black secondary name table in line interrupts, which can be done safely. The Japanese version gets away with a smaller name table due to the mirroring, which allows it a bit more space for tiles. Another game achieving the same effect (two-way scrolling with a status bar) is Gauntlet, which achieves a vertical status bar by drawing the whole status as sprites, and then masking the moving boundary tile location by also drawing a column of black sprites over it. This is hugely wasteful of sprites given the 8 sprite horizontal limit - but then the gameplay hardly uses them.

kusfo Joined: 29 Mar 2012 Posts: 886 Location: Spain	Posted: Wed Apr 19, 2017 8:01 am
kusfo Joined: 29 Mar 2012 Posts: 886 Location: Spain	Thanks guys!, very nice explanation! I'll also check Gauntlet. I know it's using tilemap for displaying enemies, but it'll be interesting to see their technique for status bars

vingazole Joined: 20 Feb 2008 Posts: 118 Location: Saintes, France	Posted: Wed Apr 19, 2017 10:29 am
	You should also take a look at this game : Sylvan Tale On YouTube :

kusfo Joined: 29 Mar 2012 Posts: 886 Location: Spain	Posted: Wed Apr 19, 2017 10:46 am
kusfo Joined: 29 Mar 2012 Posts: 886 Location: Spain	thanks! I'll take also a look at it!

Maxim Site Admin Joined: 19 Oct 1999 Posts: 14740 Location: London	Posted: Wed Apr 19, 2017 9:30 pm
	Hmm, that's an interesting one: an alternate tilemap is used for the "windowing" for text and status, and the status bar is itself drawn into tiles (and the tilemap) to offset the scrolling, so the 16px we see of that tilemap always shows the same 16px of the status area - with a little use of sprites to reduce the drawn-in tile count. The way it animates the "window" up and down is a very nice touch, too. On a side note, the text scrolling in the "window" is also done by drawing into the tiles, which is why it's a bit jerky - the number of tiles to update then exceeds what is possible in one frame. It also means it could fairly easily have a variable-width font in the translation, since the VRAM resources are all already there...

kusfo Joined: 29 Mar 2012 Posts: 886 Location: Spain	Posted: Thu Apr 20, 2017 7:25 am
kusfo Joined: 29 Mar 2012 Posts: 886 Location: Spain	As I have used lately only Emulicious, I have found that Meka is still more reliable when trying to have a grasp in how raster effects are working. Moreover, I think that there's no way to change the base adress for the tilemap in emulicious, is there? I have to say that the status bar in Sylvan Tale looks really nice!

Calindro Joined: 14 Apr 2013 Posts: 624	Posted: Thu Apr 20, 2017 5:44 pm
Calindro Joined: 14 Apr 2013 Posts: 624	kusfo wrote Moreover, I think that there's no way to change the base adress for the tilemap in emulicious, is there? I think you should try again. :)

eruiz00 Joined: 28 Jan 2017 Posts: 556 Location: Málaga, Spain	Posted: Sun Apr 30, 2017 7:12 am
	Interested. ... so i can put an lineh interrupt handler and check if i am on first 16 lines ... But dont understand what to do to fill on black... can some one illustrate with (c better for me, although asm could be valid) code? An example would be great!

Maxim Site Admin Joined: 19 Oct 1999 Posts: 14740 Location: London	Posted: Sun Apr 30, 2017 10:28 am
	Line interrupts are a pain because they reload the counter before the interrupt happens, so for example you set it for 16, it fires and you set it to ff, and it fires on line 32 anyway. To blank the screen you can either turn it off, or change to a name table showing blanks. The latter gives you the option of not being purely blank.

Maxim Site Admin Joined: 19 Oct 1999 Posts: 14740 Location: London	Posted: Sun Apr 30, 2017 10:31 am
	Another example came to mind: Cool Spot (and Global Gladiators, which is the same engine) do it by redrawing the whole name table when it scrolls 8px, then turning off the screen for 8px to hide the extra lines, then having blank tiles at the bottom with sprites for status.

hang-on Joined: 23 Mar 2013 Posts: 611 Location: Copenhagen, Denmark	Posted: Sun Apr 30, 2017 7:46 pm
	sverx's compo-entry might also be relevant: http://www.smspower.org/Homebrew/AngunaThePrisonDungeon-SMS - I have had that one filed under "interesting statusbar w. scroll" since then :)

eruiz00 Joined: 28 Jan 2017 Posts: 556 Location: Málaga, Spain	Posted: Sun Apr 30, 2017 9:20 pm
	That was what i have searching. Thanks hangs!!!

sverx Joined: 05 Sep 2013 Posts: 3827 Location: Stockholm, Sweden	Posted: Thu May 04, 2017 9:03 am
	unfortunately that solution is very very slow, eating up a lot of CPU :\| Which means: I would no longer use it. Having the health bar vertical and made with sprites would be better (also, you would get it over-imposed onto background, which is nicer than having black backdrop as in AngunaSMS)

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