Hey, not sure where to post this but I thought it was a little interesting, so here it goes.
I've just started experimenting with scrolling where I've added the ability to change scroll values while my game is paused. If I run the game in an emulator (fceux/mesen) and scroll to an area where I have no tiles loaded, it will just show black. However, when I try this on real hardware I get different kinds of garbage tiles:
PAL NES modded with Famicom PPU, NTSC crystal and NESRGB
https://drive.google.com/open?id=1Ty6gzQS6oC4K84drIva7KNNcrGBSXAGT
PAL NES modded with NESRGB
https://drive.google.com/open?id=1IDvoxL6gUXkdYRU4pxzJrkEilYGRwSHy
PAL Famiclone system (unmodded)
https://drive.google.com/open?id=1rYAu9EdsDzJST5GBCgp0l9H4flIfW5Ng
What I'm curious about is whether this is coming from the PPU itself or the VRAM chip? Currently it's a bit of an annoyance, as the garbage flashes on screen whenever the machine is turned on or the game is reset. It only shows up on half the screen though, so I guess maybe the scroll is not being correctly setup on the first frame(s) and doing so might fix the issue.
Anyways, any knowledge into this would be interesting to hear.
Cheers!
I've just started experimenting with scrolling where I've added the ability to change scroll values while my game is paused. If I run the game in an emulator (fceux/mesen) and scroll to an area where I have no tiles loaded, it will just show black. However, when I try this on real hardware I get different kinds of garbage tiles:
PAL NES modded with Famicom PPU, NTSC crystal and NESRGB
https://drive.google.com/open?id=1Ty6gzQS6oC4K84drIva7KNNcrGBSXAGT
PAL NES modded with NESRGB
https://drive.google.com/open?id=1IDvoxL6gUXkdYRU4pxzJrkEilYGRwSHy
PAL Famiclone system (unmodded)
https://drive.google.com/open?id=1rYAu9EdsDzJST5GBCgp0l9H4flIfW5Ng
What I'm curious about is whether this is coming from the PPU itself or the VRAM chip? Currently it's a bit of an annoyance, as the garbage flashes on screen whenever the machine is turned on or the game is reset. It only shows up on half the screen though, so I guess maybe the scroll is not being correctly setup on the first frame(s) and doing so might fix the issue.
Anyways, any knowledge into this would be interesting to hear.
Cheers!