Search found 207 matches

by za909
Tue Jun 02, 2020 12:57 pm
Forum: Homebrew Projects
Topic: FROM BELOW [NES Homebrew] OPEN BETA
Replies: 72
Views: 9594

Re: What's Kraken (Tetris-like) [WIP NES Homebrew]

Hi, this sounds like an interesting little project. I'd be interested to try and put a small sound engine together (based on how much RAM, CPU time, ROM it should use, and other possible restrictions, how much space can I use for DPCM samples, etc.) if you think I'm "worthy" haha. You can check out ...
by za909
Sat May 16, 2020 10:39 am
Forum: NESdev
Topic: Mesen Debugger - Feedback/Feature Requests? (2018 edition)
Replies: 201
Views: 103665

Re: Mesen Debugger - Feedback/Feature Requests? (2018 edition)

Hi, I'd like to make a suggestion. During my DPCM-PCM endeavors I really could've used some of the still hidden stats of the APU, namely the 8-bit DPCM buffer state, which if I am not mistaken is implemented as a bit shifter, so there is no separate bits remaining counter. Seeing the state of this w...
by za909
Fri May 15, 2020 1:08 am
Forum: NES Graphics
Topic: Poll: How would you prefer a first-person shooter on the NES to look like?
Replies: 21
Views: 4344

Re: Poll: How would you prefer a first-person shooter on the NES to look like?

I wonder if lighting like this is possible on the NES. It really adds a lot to the mood of the level, like you are in a scary, enclosed space: https://m.youtube.com/watch?v=ieCqOjwh3fA
by za909
Thu May 14, 2020 1:09 am
Forum: NESdev
Topic: Linear interpolation overtones
Replies: 10
Views: 1954

Re: Linear interpolation overtones

I have spent a few days to implement this idea, and I got mixed results... Overall the sound is much noisier than before, though it seems to be better with low frequencies too. Sometimes those harmonics from before are still present, even though this time I can continously interpolate with the DPCM ...
by za909
Thu May 07, 2020 1:29 pm
Forum: NESdev
Topic: Linear interpolation overtones
Replies: 10
Views: 1954

Re: Linear interpolation overtones

I think lidnariq has the right answer. I agree. The samplebufferprev variable is a copy of the sample that was sent to $4011 about 90 cycles before, and had gone through an lsr long before that (in the previous IRQ). I have a very odd mixed method of buffering every odd sample, and sitting around h...
by za909
Thu May 07, 2020 2:23 am
Forum: NESdev
Topic: Linear interpolation overtones
Replies: 10
Views: 1954

Re: Linear interpolation overtones

Thank you for the answers. I am using unsigned 8-bit PCM, which is lsr-d once to discard the lowest bit that can't fit in the $4011 register. These are summed and divided by 2, I will post the relevant code later. (The next improvement is to add compatibility with the output of my external pre-proce...
by za909
Wed May 06, 2020 2:23 pm
Forum: NESdev
Topic: Linear interpolation overtones
Replies: 10
Views: 1954

Linear interpolation overtones

I have attempted to add linear interpolation samples to my now working PCM stream. I have run into some strange wave physics phenomenon I believe, but there is a possible explanation that stems from the code, I just don't know if it is a correct answer. So to demonstrate the horrible noise that I cr...
by za909
Wed May 06, 2020 4:45 am
Forum: NESdev
Topic: VRC7 cycle timer IRQ - won't run for me
Replies: 3
Views: 1858

Re: VRC7 cycle timer IRQ - won't run for me

Even though the issue was minor, I'd be interested to know how much you can save by doing register writes like that. There might not be 42 cycles of IRQ-related overhead, but I can't imagine there being a huge benefit (acknowledge/restart cycle counter, + getting in and out of the IRQ). It would als...
by za909
Wed May 06, 2020 12:50 am
Forum: NESdev
Topic: IRQ nesting due to OAM DMA
Replies: 9
Views: 1787

Re: IRQ nesting due to OAM DMA

The solution seems to work well now, there are still a few IRQs happening close to eachother sometimes soon after exiting NMI, but there is no more problematic clobbering for now, and OAM DMA delaying a few samples is barely audible on its own (a quiet 60Hz buzz is heard during very quiet passages i...
by za909
Tue May 05, 2020 1:19 pm
Forum: NESdev
Topic: IRQ nesting due to OAM DMA
Replies: 9
Views: 1787

Re: IRQ nesting due to OAM DMA

If vblank has begun and not ended, and $2002 has not been read, turning NMI back on will immediately fire NMI. Bases Loaded II depends on this . However, turning NMI on or off at exactly the right side of the picture can cause visible artifacts in some cases due to race conditions on $2000 writes v...
by za909
Tue May 05, 2020 5:04 am
Forum: NESdev
Topic: IRQ nesting due to OAM DMA
Replies: 9
Views: 1787

IRQ nesting due to OAM DMA

I have discovered an issue with my PCM player project in Mesen that is very serious and can easily crash a game once implemented in one. Namely, there is a particular alignment of DMC IRQ, NMI and OAM DMA that can cause two IRQs to be nested in eachother, clobbering the variables for the IRQ at the ...
by za909
Mon May 04, 2020 11:28 pm
Forum: NESemdev
Topic: Mesen - NES Emulator
Replies: 838
Views: 374628

Re: Mesen - NES Emulator

CHR-ROM is used instead of RAM This is most likely the cause - Mesen defaults to using the NINA-001 mapper (which is also mapper 34) when there is CHR ROM in the cart (because all commercial BNROM games use CHR RAM.) You can force mapper 34 to use BNROM by using a NES 2.0 header and specifying a su...
by za909
Sun May 03, 2020 4:24 pm
Forum: NESemdev
Topic: Mesen - NES Emulator
Replies: 838
Views: 374628

Re: Mesen - NES Emulator

Hello, I am hopefully running into an issue that IS an issue I can "report" and is not just my ignorance, but if it is I would like to apologize in advance. However, this issue has never been present on other emulators, or the PowerPak, so I'm fairly confident that I haven't suddenly messed up my co...
by za909
Thu Mar 05, 2020 11:47 am
Forum: Other Retro Dev
Topic: Apparently the SMS is better than everything
Replies: 27
Views: 16610

Re: Apparently the SMS is better than everything

To join in on the audio discussion part, I mostly agree that a lot of soundtracks sound same-ey. Especially when it comes to percussion, since the "lazy way" was to use the available noise pitches, of which there are only three, the fourth setting takes the divider from the third square channel. Cha...
by za909
Sun Sep 01, 2019 12:53 am
Forum: NESdev
Topic: The truth about the black entries of the NTSC NES:
Replies: 12
Views: 7196

Re: The truth about the black entries of the NTSC NES:

I too have been ignorant of this information until now, but one question remains for me about 1D. It's nice to have it affected by the emphasis bits, but is it "safe" on TVs when not all three bits are set at once?