gbadev.org forum archive

This is a read-only mirror of the content originally found on forum.gbadev.org (now offline), salvaged from Wayback machine copies. A new forum can be found here.

DS Misc > jEnesis DS questions

#140797 - HackModford - Wed Sep 19, 2007 9:59 pm

First of all I have to say this emulator is great!

For some reason Sonic3DBlast won't boot. nor will Sonic 2 & Knuckles. Sonic 1 & Knuckles ends up on a weird bonus screen or something but I think it's just the ROM I got.

Could someone please explain why he can't do Horizontal Scaling? He thought he couldn't do Vertical but he did. Is it like he has to rewrite the whole emulator or something? Thanks
_________________
Use your talents for God's glory!

#140804 - dantheman - Wed Sep 19, 2007 11:22 pm

We probably can't get too specific here about some of the issues. Just know that the DS only has 4 MB of RAM to fit both the emulator and the binary being emulated.

As for the scaling, from my understanding, the DS's hardware supports basic vertical scaling in tile mode at very little cost to the CPU time, while it does not support horizontal scaling unless in framebuffer mode. The hardware build of jEnesisDS uses the tile mode, and as such it can only do the vertical scaling supported by the hardware. The software build can be thought of as emulating what the picture should look like entirely in software and then sending the output to the screen as a series of images, in framebuffer mode, so horizontal scaling is possible there.

I'm not too familiar with exactly how these things work, so if I'm wrong someone feel free to correct me.