jEnesisDS 0.7.4 - Genesis Emulator for Nintendo DS

[zzt]

I cannot belive this, the 00:00 setting works, I thoght it just worked on the MMD.

It is still annoying to have to go back to set the clock 00:00 each time, but I can play it now and it seriously ROCKS

I just hope that Lordus can fix this, then it would be the best emulator ever!

[Lordus]

figured id throw this in as well, in shinobi 3 return of the ninja master the soundtrack is speeded up heavily, just thought id pass that on

I can't reproduce that with any setting. I played along for a while with Kega, and they stayed almost perfectly in sync.

I was just reading this again and it made me go 'oh i seeeee'


Is THAT why in Sonic some of the sprites are sometimes incorrectly displayed and so they're in front/behind things they shouldnt be. The Sonic intros where he pops up from behind the word 'SONIC', and a few cases in Sonic & Knuckles where for example a door slides open towards the ground, and you can see the sprite go underground.

And more importantly the one that actually affects the game, during the Lava Reef Zone Robotnik fight where the lava 'tilts', except in the emu it either doesnt move, or all the lava rises up and you cant see.

I always figured it would be something that was hardwired because of the DS hardware. The DS can only display 4 backgrounds you say? Hmm. Or am i completely wrong and rambling about nonsense.

Erm that sounds like a complaint. It isn't. Like i said I just assumed when I saw these things that there's nothing you can do about them. I'm just interested in how it works.

And if the DS can't display enough layers how do you get everything else to look so great?

Oh, the things you mention have multiple causes.
In Sonic for example, you have to emulate sprite limits, because it is used to mask out a portion of Sonic in the intro screen, for example. The Genesis can just display a certain number of sprites and/or sprite pixels per line. Even sprites that are not visible on screen count for this limit. (The DS, or any console have that limitation, too, just that the DS can display a lot more sprites per line). Maybe i can handle that later.

Another problem is priorities. The sprite priorities on the Genesis work differently than for the DS. Normally sprites are displayed in the order they appear in the sprite table (from front to back), so sprite 0 will be above sprite 1. This is true for the Genesis and the DS, but the sprites also have a priority flag, which determines, if they are in front or behind a background layer. The problem is, that on the Genesis, the inter-sprite priority (list position) is more important than the sprite priority flag. So if sprite 0 has low priority and sprite 1 has high priority (flag), and they share the same space, then sprite 0 will still be displayed on top of sprite 1. If there are background pixels between them, this will cause sprite 1 to be masked out where it collides with sprite 0 and you will just see the bg there. (I hope that is somewhat understandable).
Some games use that exactly for that purpose, to mask out portions of sprites.

The DS has double the amount of layers than the Genesis, so it should be enough. Besides the 4 layers it has, you can also display sprites in 4 planes. I just need all of those 4 layers, because of the per tile priority in the Genesis layers (which make it possible to place the 2 layers in practically 4 planes). On the DS, you can just set the priority for the complete BG layer.

The biggest problem though is, that the DS has "just" 1024 tiles that can be used PER layer. Altogether that's more than the Genesis can use, just that it can address all 2048 tiles in any BG. The tiles are dynamically allocated and deallocated to make up for that, but if a game really uses more than 1024 tiles at once, there is a problem. In cases like that, jEnesisDS constantly "recreates" the whole screen, if "Force Update" is ON. Still there will be glitches, like in the Comix Zone title screen.

[zzt]

Any hope for a Games'n'Music fix Lordus?

[Lordus]

Any hope for a Games'n'Music fix Lordus?

I'm pretty sure that there is hope. I just don't know yet, what exactly causes the problem.
Of course, I'll try to fix it, though.

[Spidery_Yoda]

Oh, the things you mention have multiple causes...

Well I think I understood most of that thanks .

I got a bit lost on the last paragraph, but after reading it a few times I think I understand. Are you saying that the Genesis has fewer tiles than the DS, but the Genesis can address all of its at once while the DS can't?

Well thanks for the big reply. After reading that i'm quite suprised that these sprite errors are as rare as they are. It sounds like a nightmare trying to get everything in the right order.

[Lordus]

Well I think I understood most of that thanks .

I got a bit lost on the last paragraph, but after reading it a few times I think I understand. Are you saying that the Genesis has fewer tiles than the DS, but the Genesis can address all of its at once while the DS can't?

Well thanks for the big reply. After reading that i'm quite suprised that these sprite errors are as rare as they are. It sounds like a nightmare trying to get everything in the right order.

Sorry, maybe i went a bit overboard Basically it's like you say. The problem is that the DS can use 1024 tile indexes per BG, the Genesis 2048. In practice it can't, because that would take up all of the VRAM, but as long as it uses more than 1024, it's a problem. Normally a game doesn't do that though, mostly just in start screens or intros, where detailed images are displayed.

It's actually very simple with the sprites, i just order them in the same way, they are on the Genesis, just that this doesn't always look like intended, due to what i described before. I will look into improving it later.

[puslar_t]

Lordus thanks for updating this great emulator. I think Racketboy is going to feature it soon. I find it disappointing the DS isn't so hot tech-wise for emulation (though jEnesisDS, SNEmulDS and NeoDS have done wonders).. I hope you're on board with the next iteration of Nintendo's handheld (I don't think it'll be long now, thanks to the PSP's recent strong performance)

[crookedmouth]

Games N Music users, try running this version through Spinal's Menu 1.2.Worked for me without needing to use clock reset method. I attached it to help.

[TechRat]

Games N Music users, try running this version through Spinal's Menu 1.2.Worked for me without needing to use clock reset method. I attached it to help.

This worked for me too. It even ran other apps that I normally had to launch through DSOrganize (Arcomage, ApprenticeMinus), and it looks great. I'll be using this as my app loader from now on. Thanks so much for pointing this out!

[crookedmouth]

Cool glad to hear it!
Thank you Spinal, and of course thank you Lordus!

Save States work with this too, where as before you would lose your save states after a power down.