I'm mostly self-taught. got interested into things like emulation, level editors, etc... that are technically cool and make use of things the way they weren't intended, etc

hax

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Kuribo64

you should stick to revision d2d7c20208847f4230b406189a90195e708dfc72 for now.


I haven't updated CMakeLists.txt, and haven't coded the Linux side of the new features yet.

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Kuribo64

that game (or rather, its special save type) isn't supported yet in melonDS

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Kuribo64

local multiplayer?

it should work between two computers, yeah. you need to make sure to enable the 'bind to any address' option in emulation settings.

there's no guarantee it will work, though. local multiplayer has tight timing, so network lag might get in the way.

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Kuribo64

it seems to work the same for all games, even Pictochat is constantly exchanging packets every 4ms or so.

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Kuribo64

download play was reported to work with some titles, but not always.


the operation is the same as for multicart btw, it's nifi

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Kuribo64

yeah that works for typical save types

but WarioWare DIY uses a special one, not supported

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Kuribo64

Posted by Wifall

The only difference between melonDS saves and desmume's one is the save data footer at the end of the file? Or is there something more?

nope, that's pretty much it

Posted by Wifall

Also, if there are ANYTHING wrong with the save( a changed byte in the middle of it) does the save will load or not?

depends on the game. melonDS does not check the contents of the savefile.

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Kuribo64

no problem. nothing wrong with ignorance.

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Kuribo64

if you run 0.7.3 from cmd, you get the console output


anyway: https://github.com/Arisotura/melonDS/blob/master/src/NDSCart.cpp#L402

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Kuribo64

as long as there's an ethernet cable going into the computer, it should be okay

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Kuribo64

client->host replies tend to get lost (or rather, miss their reply window and be discarded).

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Kuribo64

reply bits may get lost, as seen in Pictochat

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Kuribo64

it's on the TODO list, it's just not going to happen tomorrow

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Kuribo64

the idea is interesting, but I really wonder how that works, especially for 2D elements. the resolution is fixed at 256x192 and much of the hardware is designed with that in mind.

so apparently all I'd need on my side would be changing the aspect ratio of the screens I guess. mh

might make more sense to do that once we have upscaling, tho.

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Kuribo64

you probably need to set up your connection; you might be trying to connect using existing firmware data that are obsolete.

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Kuribo64

which is where we try to figure out how the GPU does divisions, because it's weird

I don't think they embedded a divider for each purpose tho?



theory

GPU has a general-purpose unsigned 32bit divider

some special measures are taken before using it, to ensure that numerator and denominator a) are positive and b) fit within 32 bits



viewport transform

barring overflow cases (when W is greater than 0xFFFFFF -- it gets truncated to 24 bits)

sX = ((X + W) * sW) / (W*2)

when W is greater than 0xFFFF, (W*2) loses two bits of precision (effectively taking one bit from W).

so, first, assuming W within 0001..FFFF

X: -FFFF..FFFF (has to be between -W and W)
W: 0001..FFFF
sW: 000..1FF

X+W: 00000..1FFFF -> 17 bits
((X + W) * sW): 26 bits
(W*2): 17 bits

next, when W is greater than FFFF

X: -FFFFFF..FFFFFF
W: 010000..FFFFFF

X+W: 0000000..1FFFFFF -> 25 bits
((X + W) * sW): 34 bits
(W*2): 26 bits

denominator is shifted right by two, same for numerator??

TODO: how is numerator handled? presumably it has to always fit within 32bit unsigned range, which would explain the precision loss at denominator

numerator W doesn't lose precision



interpolation

((x * w0) << shift) / ((x * w0) + (xmax-x * w1))

x: 00..FF (in practice, never going to be greater)
xmax-x: same
wn: 0001..FFFF
shift: 8 or 9

numerator: 8+16+shift
denominator: 26 at most

numerator reaches 32 bits along X, 33 bits along Y

that would explain the interpolation quirks along Y: reducing W's to 15 bits so that the numerator fits within 32 bits

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Kuribo64

1. you mean 'settings -> savestate settings -> separate savefile'. this feature is disabled by default in 0.7.4 tho, but can't hurt to check. also, savestates aren't the same thing as save files.

2. same here. looks like your file is a savestate. you can't do anything with that, other than loading it into DraStic.

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Kuribo64

seems you're confusing save files and savestates

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Kuribo64

you need to grab the .dsv file from DraStic and remove the footer with a hex editor, or try some online save file converter.

savestates aren't gonna help you there as they are emulator-specific.

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Kuribo64