How did they blend this on the SNES? *pic included*

[TheouAegis]

A lot of SNES games used blending and alpha channels for some neat or spooky effects. GeGeGe no Kitarou on the SNES uses alpha channels a lot, but I encountered "screen" blending for the first time (as far as I'm aware) in an SNES game and can't figure out how they blended three parts.

Ok, first, here's the image (direct from the game excluding any unnecessary layers):


First, the ectoplasm is on BG1 (BG layer 1), while the arms and head (as well as poor Kitarou) are on OBJ (object layer). Now, simple logic, in my Paintshop Pro I should be placing both the arms and the head on the same top layer, then put the ectoplasm on the lower layer. When I set the layer blend for OBJ (top layer) to "Screen" I get the resulting head+ectoplasm image seen in this picture. However, the legs get completely screened out, which is not the case in the game, as you can see in the picture. I tried doubling up the legs -- putting another set on the bottom level below the ectoplasm (unrealistic as this would not have been done on the SNES) -- but the legs were still screened too much.

The legs as you see them in that picture are the natural color as long as they're outside the ectoplasm. And no, there isn't a palette swap going on there, that image is the result of a blending that I can't seem to duplicate in Paintshop Pro.

Anyone have any ideas?

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If anyone wants to try to get the resulting image in that screenshot, here is my sprite sheet with the current fruits of my labor. If you figure out how to get the proper blending, please let me know.

[Chris2Balls [:B]]

Much as I don't know how to solve your problem (could it be a flickering frequency that's causing you this problem?), I'm posting to say that I find this very interesting; have you uploaded any videos of this? What do you mean by screen blending?

[Kelvin]

They may have used alpha maps or possibly even separate sprites with surface masks. Though it looks a lot like additive blending, where it adds color to get closer to white. It looks natural on the black part because it's adding to zero which just results in the original color. Too bad you can't just ask the developers.

[Ultimecia]

I know some SNes games got water with a semi-transparency effects that usually the emulators don't shows is as it should be. Maybe this game uses the same mechanic in a different way?

[Deathbringer]

Thank god someone made vSNES. Here's how it's done.
This is a screenshot of the game:

Spoiler

I don't know why the corner is weird though.

And this is how the layers are broken down:

Spoiler

Normal Screen -> BG1 -> BG2 -> BG3 -> BG4 -> SPR |BG4 doesn't seem to be used in the game.|

Internally this is how the game is broken up program wise:

Spoiler

The first thing you'll notice is that the graphics are garbled, just ignore it. The second thing you will notice is how the game is layered, the Sprites are between the various layers. This explains why Theou couldn't get the results he wanted, the ectoplasm which may be priority 1 or 0 but will always be layered above Sprite p0-2 (since 3 would be the player and would probably never get behind it).

Also note the 'BG3 p1 on top,' that overrides the programing and that is why the grass is in front of the character even though the layer would be behind everything else otherwise.

How the layers are done:

Spoiler

ZSNES Screen -> vSNES p0/1 -> vSNES p0 -> vSNES p1
BG1


BG2

Since the graphics are garbled, Priority 1 is the grass above the status bar.

BG3


Sprites

ZSNES Screen -> vSNES p0/3 -> vSNES p3
Priority 3 is used for the character, 0 is probably the ghost that goes behind the tree. Since I'm basing this from the first level, Theou'll understand about the ghost. On topic, the legs and head are either Sprites priority 1 and/or 2.

I really hope this is understandable.

[TheouAegis]

Whoa that's a nifty feature. I'll have to d/l vSNES now. I'll just include my messed-up version in my sprite sheet and keep my vSNES findings to myself.

And yes, it is different with the layers turned off, I did notice that. I'll post a comparison screenshot for those who want to see what exactly I'm talking about. I did notice without the legs I could mimic almost perfectly (since I couldn't use the legs) what the actual image looked like if I screened the head and reduced the opacity of the ectoplasm (or I think that's what I did...) so I know alpha channels were indeed in use. It's actually not as impressive in game because you don't see the "screening. There was a GameMaker program someone made to compare blend modes and I was thinking of fiddling with that using the sprites, but haven't gotten around to it. I know some GM blend modes aren't easily replicable in PSP and was thinking maybe the SNES was similar.

But yeah, i'll post a pic in a couple minutes.

EDIT: nevermind. I worked 14 hours today and have to work another 8 or 10 more tomorrow. I don't feel like playing through the game again tonight.