Search found 429 matches

by James
Wed Feb 25, 2015 7:16 pm
Forum: NESemdev
Topic: Micro Machines glitches
Replies: 88
Views: 27029

Re: Micro Machines glitches

Interestingly, it positions sprite 0 toward the top-right of the screen and it relies on that hit to coordinate those lines in the middle of the screen. I wonder if it is doing very careful timing based off of that hit. The game spins waiting for that sprite 0 hit immediately before jumping to the ...
by James
Tue Feb 24, 2015 4:14 pm
Forum: NESemdev
Topic: Micro Machines glitches
Replies: 88
Views: 27029

Re: Micro Machines glitches

Does that mean that $2004 returns the contents of secondary OAM?...You also seem to be implying that $2004 returns the contents of secondary OAM. What address/offset into secondary OAM is accessed (if it is accessed)? $2004 reads return the contents of secondary OAM during these phases: Cycles 257-...
by James
Tue Feb 24, 2015 3:03 pm
Forum: NESemdev
Topic: Micro Machines glitches
Replies: 88
Views: 27029

Re: Micro Machines glitches

What's the concept behind the hack? Micro Machines reads $2004 around dot 320. If the read occurs before dot 320, it needs to see a value with the high bit set (implemented properly, the read would return $FF because it would take place while the PPU is fetching from an empty sprite slot). If the r...
by James
Tue Feb 24, 2015 12:58 pm
Forum: NESemdev
Topic: Micro Machines glitches
Replies: 88
Views: 27029

Re: Micro Machines glitches

re: mapper 2 vs. 71: http://wiki.nesdev.com/w/index.php/INES_Mapper_071 As far as $2004 reads go, this (hack) should be enough to make Micro Machines work: if (rendering) { if (current_cycle < 64) return_value = 0xFF; else if (current_cycle < 256) return_value = 0x00; else if (current_cycle < 320) r...
by James
Tue Feb 24, 2015 10:32 am
Forum: NESemdev
Topic: Micro Machines glitches
Replies: 88
Views: 27029

Re: Micro Machines glitches

It's referring to the behavior of $2004 reads during visible scanlines described here: http://wiki.nesdev.com/w/index.php/PPU_ ... evaluation
by James
Tue Feb 10, 2015 12:22 pm
Forum: NESemdev
Topic: Blargg's Flowing palette demo
Replies: 5
Views: 2273

Re: Blargg's Flowing palette demo

Micro Machines relies on the palette rendering trick.
by James
Sat Feb 07, 2015 11:52 am
Forum: NESemdev
Topic: APU sound buffering strategies
Replies: 4
Views: 1909

Re: APU sound buffering strategies

nemulator's methodology is most likely the best choice, but it may or may not require newer Windows (ex. Vista or 7 onwards). nemulator requires >= Windows Vista, but this method does not. It should work with XP or any other OS, in theory. Windows/DirectSound may have an advantage here, though, bec...
by James
Mon Jan 05, 2015 10:07 am
Forum: NESemdev
Topic: MMC3 IRQs?
Replies: 2
Views: 1666

Re: MMC3 IRQs?

Make sure that you're implementing IRQ checking correctly. By that, I mean that the CPU will (generally) check for a pending IRQ on the second-to-last cycle of an instruction.
by James
Sat Dec 13, 2014 5:30 pm
Forum: General Stuff
Topic: Smooth scrolling in NES emulators?
Replies: 11
Views: 4130

Re: Smooth scrolling in NES emulators?

Try nemulator. Smooth scrolling in both windowed and full screen modes.
by James
Fri Oct 24, 2014 8:05 am
Forum: NESemdev
Topic: my nes emulator ffnes
Replies: 16
Views: 8391

Re: my nes emulator ffnes

It doesn't compile out of the box with VS 2013. Complains about not being able to build an MFC project with a non-Unicode character set. Switching to Unicode (from Multi-byte) results in a bunch of errors. I gave up at that point.
by James
Thu Sep 18, 2014 5:56 am
Forum: NESemdev
Topic: Audio and Video Sync
Replies: 17
Views: 5322

Re: Audio and Video Sync

Anes wrote:I did it!! thxs for the info!!
Cool - glad you got it to work!
by James
Fri Sep 12, 2014 4:19 am
Forum: NESemdev
Topic: Audio and Video Sync
Replies: 17
Views: 5322

Re: Audio and Video Sync

Is this a cpu waste? should i generate more samples? for example taking the output every 2 frames that would be 744*2? It's unlikely that either choice has a significant impact on CPU utilization. Profile it and see. However, it is probably better to update the buffer every frame as that would redu...
by James
Thu Sep 11, 2014 6:13 am
Forum: NESemdev
Topic: Audio and Video Sync
Replies: 17
Views: 5322

Re: Audio and Video Sync

But, the thing now is about getting the right VSync Hertz. We got D3D9::GetAdapterDisplayMode() that retrives the VSync Querying for this value really doesn't help. The OS may report 60Hz but the true value may be 59.99Hz. A minor difference, but it will eventually cause problems. And there are oth...
by James
Wed Sep 10, 2014 4:05 pm
Forum: NESemdev
Topic: Audio and Video Sync
Replies: 17
Views: 5322

Re: Audio and Video Sync

I cannot get constantly 735 samples per frame. It oscillates between 735,734, 736. Could be that my problem? Not really. Assuming you're syncing to vblank, if your monitor's refresh rate is EXACTLY 60Hz, and your sound card is outputting at EXACTLY 44.1kHZ, then generating 735 samples per frame (or...