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Old 02 February 2023, 01:26   #41
saimon69
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Quote:
Originally Posted by Galahad/FLT View Post
OSD? Overlay sprite display???
I think is refering to scores, high scores on top and lives on bottom right
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Old 02 February 2023, 21:31   #42
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Yeah on-screen display probably. I like to use "hud" myself.
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Old 06 February 2023, 00:26   #43
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new video. You may think that it's worse than the first one (which is true color-wise) but palette optimizations haven't been applied yet, hiscore font color is also off, and deleted by shots and all. This is a 180 degree turn vs the previous approach which used the actual 128 colors for tiles & sprites, and was pretty wasteful in terms of resources.

With that new approach, a ECS version could be done, but with 8+8 colors (+ sprites) it would be really bland.

[ Show youtube player ]
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Old 06 February 2023, 03:45   #44
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Originally Posted by jotd View Post
yes, slow vertical scrolling, shooter. Looks like it

I wonder how games manage OSD and background layers. For instance do Hybris/Battle Squadron/SWIV use dual playfield? How do they manage OSD?

Using dual playfield makes a huge difference in performance because you don't have to restore the background when moving bobs, just blank it.

I know there's a trick on SWIV to exploit an undocumented ECS feature to create a gradient in score (AGA can't replicate it).
As Galahad said the OSD is probably sprites, however it should be cheap enough if needed to have an extra bitplane fir the OSD vertical positions no?
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Old 06 February 2023, 08:24   #45
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Quote:
Originally Posted by jotd View Post
new video. You may think that it's worse than the first one (which is true color-wise) but palette optimizations haven't been applied yet, hiscore font color is also off, and deleted by shots and all. This is a 180 degree turn vs the previous approach which used the actual 128 colors for tiles & sprites, and was pretty wasteful in terms of resources.

With that new approach, a ECS version could be done, but with 8+8 colors (+ sprites) it would be really bland.

[ Show youtube player ]
I think it's an excellent result.
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Old 06 February 2023, 09:26   #46
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Originally Posted by lmimmfn View Post
As Galahad said the OSD is probably sprites, however it should be cheap enough if needed to have an extra bitplane fir the OSD vertical positions no?

no the OSD is another tile layer. Like dual playfield but only 1 bitplanes. The machine can have 64 sprites simultaneously too, with 8 colors per sprite!


One extra bitplane won't do. I'm already using 4+4 bitplanes for tiles & sprites. That would degrade sprites even more.


I'm going to refresh those tiles when they're overwritten by bobs, that will be not too frequent and pretty cheap.
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Old 06 February 2023, 21:32   #47
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I was just experimenting with the 32 colour Xevious sprites+backgrounds, no intention of doing it on the Amiga

To get the whole thing down to 16 colours I you lose the shades of gold on the big mothership and go greyscale, even then it's a lot of work. Atari ST only has 8 greyscales anyway and Amiga SEUCK is only 16 colours max too which is why I messed about with it.

Most people with an A500 had that A520 up the back so subtle differences would be hard to tell on a TV back then unless you had an RGB video cable in use.

I would never have guessed Xevious is pushing as many colours as Konami's Gradius, fascinating checking it out.
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Old 06 February 2023, 22:35   #48
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AGA version would have 32 colors, and more when using sprites which could approach the original. But not all moving objects can be sprites, so the palette would have to match the rest, or be slightly more colored just to make it more colorful, regardless of the original.

Still work to do. I'm going to fix the bomb & enemies attacking from nowhere, then the game will be playable (as Mark has almost completed the coding) with glitches.
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Old 07 February 2023, 00:36   #49
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Map + assets in 16 colors. 3 alt palettes plus the original (last).
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Old 07 February 2023, 00:57   #50
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this could just be what I need!

What I need is more like separated 16 color palettes for map / sprites (make it 8/8 for the possible ECS version). But I can already work them out from those. It's great!
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Old 07 February 2023, 03:33   #51
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To get it down to 16 colours I just recoloured the gold mothership to greyscale and HAMconvert was happy with that. I was thinking about seeing what SEUCK on the ST could do with it as that has better scrolling routines on the STFM than anything I can do in m68k!
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Old 07 February 2023, 08:31   #52
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aah now I see why I couldn't reduce to a good result: the title tiles aren't included in this map and they probably use different colors.

This night I figured it out: as the title can't be displayed at the same time as the scenery, I could switch palettes when the title is displayed

Made good progress yesterday. Now game is playable. It's going to be real!
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Old 07 February 2023, 19:09   #53
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Made good progress yesterday. Now game is playable. It's going to be real!

Woohoo!
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Old 07 February 2023, 19:14   #54
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I'm very pleased how it is turning out because at start when Mark contacted me I really thought I wasn't going to be able to interface with his API, but it's pretty well designed and (rather) platform agnostic even if more designed for the NeoGeo lol

Plus there's a scrolling and I'm not too experienced with that. It appears that the game handles the scrolling very simply. You just have to repeat the last tiles when drawing them to simulate the 512 pixel high wrap so it works well.
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Old 07 February 2023, 19:22   #55
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Awesome jotd !
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Old 07 February 2023, 19:54   #56
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Looking forward to play it
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Old 07 February 2023, 23:44   #57
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Quote:
Originally Posted by jotd View Post
aah now I see why I couldn't reduce to a good result: the title tiles aren't included in this map and they probably use different colors.

This night I figured it out: as the title can't be displayed at the same time as the scenery, I could switch palettes when the title is displayed

Made good progress yesterday. Now game is playable. It's going to be real!
Nice.
Well, when I saw you were talking about how the game uses that many colors and you wanted to go more than 16 colors, I thought this can't be right. Even if the game does use a lot of colors indeed, the pixel art is very primitive, so with a proper conversion it should have gone quite close to the original, even on 16 colors only.

A couple notes for the examples I posted. A and B have the enemies (except the boss) in their original colors (no color loss/change from the arcade) and then I only did a few compromises with the tileset to get to 16. While C has one dark color different for the enemies, making tileset colors a bit more accurate.

Overall most of the extra colors removed from the tileset were completely inconsequential, mostly used as (badly done) antialiasing around some shapes. Replacing these brought no quality losses to the result practically. The tileset also uses a few unique greys, these were replaced with greys used in the ships, which brings a slight change in brightness for these map parts. Finally the map also uses 3 unique browns which do occupy large areas (around the airport and the 'Nasca lines' area). All variants A, B and C compromise these colors in different ways.

Given these results, if you went with 32 colors instead, then you could be 99.9% accurate to the arcade (even having the boss in its original colors). Having said that, also dual playfield (8+7) is possible with little color loss (vs the 16 color versions). In this case I'd split the yellow, red and grey ramp colors from the tileset colors.

Note also that the above tilesets assume no sprites usage. I guess you can use these for the projectiles (in which case you could have them in their original colors and not sharing the palette). And you can this way (perhaps) also flash red on the enemies the way the arcade does it.
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Old 08 February 2023, 00:03   #58
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thanks Tsak. Really helpful. Yes, Mark told me that some colors were only used in a few pixels of the map, so no need to keep them.

But those 1982 machines were real beasts graphically wise!
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Old 08 February 2023, 00:05   #59
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I second Tsak Analysis: you can use 32 colors, have map in 32 colors while the enemies, the Solvalou sprite, crosshair and bullets uses the second pair of 16; fixed enemies on the ground can be changing tiles - most have just two states, live or dead (crater) beside the hidden towers
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Old 08 February 2023, 00:22   #60
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Xevious reduced palette

Wow, this is awesome guys, it's going to look great!

Once a reduced palette has been finalised, I might even add it as an option to the Neo Geo version, as you have oodles of graphics ROM space and two banks of palette data (I'm only using one atm).

Just wondering now which other 68K platforms will be viable with a reduced palette... X68000, Genesis? ST?
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