mirror of https://github.com/bsnes-emu/bsnes.git
3 Commits
| Author | SHA1 | Message | Date |
|---|---|---|---|
Tim Allen
|
04072b278b |
Update to v102r16 release.
byuu says:
Changelog:
- Emulator::Stream now allows adding low-pass and high-pass filters
dynamically
- also accepts a pass# count; each pass is a second-order biquad
butterworth IIR filter
- Emulator::Stream no longer automatically filters out >20KHz
frequencies for all streams
- FC: added 20Hz high-pass filter; 20KHz low-pass filter
- GB: removed simple 'magic constant' high-pass filter of unknown
cutoff frequency (missed this one in the last WIP)
- GB,SGB,GBC: added 20Hz high-pass filter; 20KHz low-pass filter
- MS,GG,MD/PSG: added 20Hz high-pass filter; 20KHz low-pass filter
- MD: added save state support (but it's completely broken for now;
sorry)
- MD/YM2612: fixed Voice#3 per-operator pitch support (fixes sound
effects in Streets of Rage, etc)
- PCE: added 20Hz high-pass filter; 20KHz low-pass filter
- WS,WSC: added 20Hz high-pass filter; 20KHz low-pass filter
So, the point of the low-pass filters is to remove frequencies above
human hearing. If we don't do this, then resampling will introduce
aliasing that results in sounds that are audible to the human ear. Which
basically an annoying buzzing sound. You'll definitely hear the
improvement from these in games like Mega Man 2 on the NES. Of course,
these already existed before, so this WIP won't sound better than
previous WIPs.
The high-pass filters are a little more complicated. Their main role is
to remove DC bias and help to center the audio stream. I don't
understand how they do this at all, but ... that's what everyone who
knows what they're talking about says, thus ... so be it.
I have set all of the high-pass filters to 20Hz, which is below the
limit of human hearing. Now this is where it gets really interesting ...
technically, some of these systems actually cut off a lot of range. For
instance, the GBA should technically use an 800Hz high-pass filter when
output is done through the system's speakers. But of course, if you plug
in headphones, you can hear the lower frequencies.
Now 800Hz ... you definitely can hear. At that level, nearly all of the
bass is stripped out and the audio is very tinny. Just like the real
system. But for now, I don't want to emulate the audio being crushed
that badly.
I'm sticking with 20Hz everywhere since it won't negatively affect audio
quality. In fact, you should not be able to hear any difference between
this WIP and the previous WIP. But theoretically, DC bias should mostly
be removed as a result of these new filters. It may be that we need to
raise the values on some cores in the future, but I don't want to do
that until we know for certain that we have to.
What I can say is that compared to even older WIPs than r15 ... the
removal of the simple one-pole low-pass and high-pass filters with the
newer three-pass, second-order filters should result in much better
attenuation (less distortion of audible frequencies.) Probably not
enough to be noticeable in a blind test, though.
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Tim Allen
|
ee7662a8be |
Update to v102r04 release.
byuu says:
Changelog:
- Super Game Boy support is functional once again
- new GameBoy::SuperGameBoyInterface class
- system.(dmg,cgb,sgb) is now Model::(Super)GameBoy(Color) ala the PC
Engine
- merged WonderSwanInterface, WonderSwanColorInterface shared
functions to WonderSwan::Interface
- merged GameBoyInterface, GameBoyColorInterface shared functions to
GameBoy::Interface
- Interface::unload() now calls Interface::save() for Master System,
Game Gear, Mega Drive, PC Engine, SuperGrafx
- PCE: emulated PCE-CD backup RAM; stored per-game as save.ram (2KiB
file)
- this means you can now save your progress in games like Neutopia
- the PCE-CD I/O registers like BRAM write protect are not
emulated yet
- PCE: IRQ sources now hold the IRQ line state, instead of the CPU
holding it
- this fixes most SuperGrafx games, which were fighting over the
VDC IRQ line previously
- PCE: CPU I/O $14xx should return the pending IRQ bits even if IRQs
are disabled
- PCE: VCE and the VDCs now synchronize to each other; fixes pixel
widths in all games
- PCE: greatly increased the accuracy of the VPC priority selection
code (windows may be buggy still)
- HuC6280: PLA, PLX, PLY should set Z, N flags; fixes many game bugs
[Jonas Quinn]
The big thing I wanted to do was enslave the VDC(s) to the VCE. But
unfortunately, I forgot about the asynchronous DMA channels that each
VDC supports, so this isn't going to be possible I'm afraid.
In the most demanding case, Daimakaimura in-game, we're looking at 85fps
on my Xeon E3 1276v3. So ... not great, and we don't even have sound
connected yet.
We are going to have to profile and optimize this code once sound
emulation and save states are in.
Basically, think of it like this: the VCE, VDC0, and VDC1 all have the
same overhead, scheduling wise (which is the bulk of the performance
loss) as the dot-renderer for the SNES core. So it's like there's three
bsnes-accuracy PPU threads running just for video.
-----
Oh, just a fair warning ... the hooks for the SGB are a work in
progress.
If anyone is working on higan or a fork and want to do something similar
to it, don't use it as a template, at least not yet.
Right now, higan looks like this:
- Emulator::Video handles the platform→videoRefresh calls
- Emulator::Audio handles the platform→audioSample calls
- each core hard-codes the platform→inputPoll, inputRumble calls
- each core hard-codes calls to path, open, load to process files
- dipSettings and notify are specialty hacks, neither are even hooked
up right now to anything
With the SGB, it's an emulation core inside an emulation core, so
ideally you want to hook all of those functions. Emulator::Video and
Emulator::Audio aren't really abstractions over that, as the GB core
calls them and we have to special case not calling them in SGB mode.
The path, open, load can be implemented without hooks, thanks to the UI
only using one instance of Emulator::Platform for all cores. All we have
to do is override the folder path ID for the "Game Boy.sys" folder, so
that it picks "Super Game Boy.sfc/" and loads its boot ROM instead.
That's just a simple argument to GameBoy::System::load() and we're done.
dipSettings, notify and inputRumble don't matter. But we do also have to
hook inputPoll as well.
The nice idea would be for SuperFamicom::ICD2 to inherit from
Emulator::Platform and provide the desired functions that we need to
overload. After that, we'd just need the GB core to keep an abstraction
over the global Emulator::platform\* handle, to select between the UI
version and the SFC::ICD2 version.
However ... that doesn't work because of Emulator::Video and
Emulator::Audio. They would also have to gain an abstraction over
Emulator::platform\*, and even worse ... you'd have to constantly swap
between the two so that the SFC core uses the UI, and the GB core uses
the ICD2.
And so, for right now, I'm checking Model::SuperGameBoy() -> bool
everywhere, and choosing between the UI and ICD2 targets that way. And
as such, the ICD2 doesn't really need Emulator::Platform inheritance,
although it certainly could do that and just use the functions it needs.
But the SGB is even weirder, because we need additional new signals
beyond just Emulator::Platform, like joypWrite(), etc.
I'd also like to work on the Emulator::Stream for the SGB core. I don't
see why we can't have the GB core create its own stream, and let the
ICD2 just use that instead. We just have to be careful about the ICD2's
CPU soft reset function, to make sure the GB core's Stream object
remains valid. What I think that needs is a way to release an
Emulator::Stream individually, rather than calling
Emulator::Audio::reset() to do it. They are shared\_pointer objects, so
I think if I added a destructor function to remove it from
Emulator::Audio::streams, then that should work.
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Tim Allen
|
67457fade4 |
Update to v099r13 release.
byuu says: Changelog: - GB core code cleanup completed - GBA core code cleanup completed - some more cleanup on missed processor/arm functions/variables - fixed FC loading icarus bug - "Load ROM File" icarus functionality restored - minor code unification efforts all around (not perfect yet) - MMIO->IO - mmio.cpp->io.cpp - read,write->readIO,writeIO It's been a very long work in progress ... starting all the way back with v094r09, but the major part of the higan code cleanup is now completed! Of course, it's very important to note that this is only for the basic style: - under_score functions and variables are now camelCase - return-type function-name() are now auto function-name() -> return-type - Natural<T>/Integer<T> replace (u)intT_n types where possible - signed/unsigned are now int/uint - most of the x==true,x==false tests changed to x,!x A lot of spot improvements to consistency, simplicity and quality have gone in along the way, of course. But we'll probably never fully finishing beautifying every last line of code in the entire codebase. Still, this is a really great start. Going forward, WIP diffs should start being smaller and of higher quality once again. I know the joke is, "until my coding style changes again", but ... this was way too stressful, way too time consuming, and way too risky. I'm too old and tired now for extreme upheavel like this again. The only major change I'm slowly mulling over would be renaming the using Natural<T>/Integer<T> = (u)intT; shorthand to something that isn't as easily confused with the (u)int_t types ... but we'll see. I'll definitely continue to change small things all the time, but for the larger picture, I need to just accept the style I have and live with it. |