Best emulator out just needs sound working and megaman wily wars...
Thanks. Sound is being worked on, but Mega Man will be problematic. It needs the EEPROM chip it uses for its save feature to be emulated to run. While the EEPROM itself is not hard to emulate (i emulated it in the jEnesis Java version), it would be hard to implement it into my code, because of the way the cpu core accesses the Genesis rom.
Great job. I'm really impressed with the quality of your emulator. I don't know how you use the 4 DS layers but as 2 layers are hardware scalable it will be great if you could, at least, scale sprites layer. In some games the life meter, score or time could be seen. Scale background layer instead of sprite layer could be fine for other kind of games (mainly scroll bet'em ups or similar). An option to select what layers scale could be the best option.
Another idea for SW scaling , if is a time consuming task, could be to allow deactivate alpha lerp filter.
Thanks again
I dont know if you tried it, but in the last version (0.4a) a software renderer is included, that uses alpha lerp and hardware scaling to fit the screen exactly, but of course its quite a bit slower and impossible to ever reach full speed. Thats why i am concentrating on the hardware renderer now.
Software scaling in the hardware renderer would be quite pointless, because it would slow down everything to be even slower than the software renderer i guess.
Hardware scaling is as you said just available for 2 layers, and just if they are not in Text BG Mode. I am using all 4 layers in Text Mode though and i need all for of them just for the 2 Genesis layers, because the Genesis has per tile priority, which the DS doesnt have. Also, the Genesis can address 2048 tiles, while the DS can just address 1024 per layer.
The way i am doing it, i can almost directly map writes to Genesis tile memory to the DS tile memory without much calculations. That is what makes it so fast. Believe me, i thought of many ways to scale in hardware, but ther is none, except i would change the whole way rendering is handled and make it probably quite a bit slower.
Now scaling just some of the layers would be a bit problematic, too.
1. If just the sprites would be scaled, they would be definately at wrong positions. Also, often sprites are composed of more than 1 sprite and there is no way to find out when, so there could be a lot of glitches.
2. If i'd use 2 layers in a mode that allows scaling, then also the tile addressing would have to be changed for those layers, as it works differently than in Text BG Mode, which would again need extra checks and calculations that make it slower. And 1 Genesis layer is represented as 2 DS layers, so scaling just one of them would look quite strange, except for some games, that dont use different priorities for the tiles at all.
