Search found 226 matches

by za909
Sat May 27, 2017 2:05 pm
Forum: NES Graphics
Topic: My "Kat" shmup game graphics
Replies: 5
Views: 4261

My "Kat" shmup game graphics

I'm slowly getting into creating some of the assets for my game (8k CHR-ROM only) and I'd like to get some criticism and ideas on how to improve myself. Generally I practice with art I receive/commission or find on the internet by using them as a base for "pixelization" as far as the mugshot and the...
by za909
Fri Mar 31, 2017 6:39 am
Forum: Newbie Help Center
Topic: NES Programming Tutorial : Interrupts
Replies: 3
Views: 2951

Re: NES Programming Tutorial : Interrupts

Two things that stood out to me:
- $2007 is the PPU_DATA register, your table makes it look like it is part of the mirorred address space.
- The iNES header is 16 bytes, not 256 (but the rest of the tutorial with the ROM addresses actually considers it 16 bytes).
by za909
Wed Mar 29, 2017 3:25 am
Forum: NESdev
Topic: Sine Wave Raster Effect with DMC
Replies: 2
Views: 1478

Sine Wave Raster Effect with DMC

For one of my stages in my game with lava at the bottom, I'd like to create a sine wave movement pattern to make things look more interesting. However, my game is small and is based on very simple cart hardware so I use the DMC for raster effects. I know that I need to do this with timed code becaus...
by za909
Wed Mar 29, 2017 3:14 am
Forum: NESdev
Topic: Why NES have too ugly arch?
Replies: 80
Views: 19045

Re: Why NES have too ugly arch?

As far as instruction sets go, sometimes I look at the Z80 set with quite some envy. It may be slow as all hell but it sure has some clever instructions that I could really use in NES programs. For example the bit tests that can test a single bit in a register or in RAM. With the 6502 you can only c...
by za909
Mon Mar 27, 2017 8:37 am
Forum: Homebrew Projects
Topic: MintaBOOM - A WIP sample-based music engine for the NES
Replies: 4
Views: 6433

Re: MintaBOOM - A WIP sample-based music engine for the NES

Minor Update: ------------- I am still working on this little project every now and then, and I have created a simple compression tool that optimizes a raw 8-bit PCM file sampled at 8 272Hz for the player. Currently the player uses a primitive 1-bit RLE compression, to make use of the MSB (since the...
by za909
Mon Mar 27, 2017 8:13 am
Forum: NESdev
Topic: Why NES have too ugly arch?
Replies: 80
Views: 19045

Re: Why NES have too ugly arch?

It takes a miniscule amount of time to read in the grand scheme of things (even with an active DMC), and even then some games opted out for an unrolled loop and had the same code repeated 8 times. It works, and honestly my question would rather be why the designers of the Mega Drive felt that a cont...
by za909
Thu Sep 01, 2016 12:12 pm
Forum: NESdev
Topic: "APU basics": register initialization question
Replies: 28
Views: 8626

Re: "APU basics": register initialization question

Based on a quick look at that page I'm extremely happy that when I started out I only ever used the APU reference to do what I wanted... part of the truth was that I had already familiarized myself with most of the APU features through Famitracker so it all made sense to me.
by za909
Wed Aug 31, 2016 3:56 pm
Forum: NESdev
Topic: Sound synthesizer using $4011, 2a03 only
Replies: 47
Views: 11315

Re: Sound synthesizer using $4011, 2a03 only

My solution to that problem is to use a byte of $AA or $55 for the timing, so the underlying square wave should be inaudibly high at rate $F. The 1-bit fluctuations caused by this sample shouldn't be too bad.
by za909
Wed Aug 31, 2016 1:41 pm
Forum: NESdev
Topic: Hiding sprites and OAM decay
Replies: 16
Views: 4840

Re: Hiding sprites and OAM decay

For the record, I'm using CHR-ROM and it's not going to be backswitched... this is supposed to be a tiny game aiming high... (1-bit BNROM-register to enable 64k of PRG) I added the gradient because CHR-ROM can't be compressed anyway... for monochrome fonts it's pretty easy by leaving out the second ...
by za909
Wed Aug 31, 2016 3:58 am
Forum: NESdev
Topic: Hiding sprites and OAM decay
Replies: 16
Views: 4840

Hiding sprites and OAM decay

I have this issue where I would like to hide sprites behind a HUD, which is at the top of the screen. The first idea I had was disabling sprites during VBlank and enabling them from an IRQ at the bottom of the status bar. Although this would be the least CPU-intensive method possible, it could be pr...
by za909
Wed Aug 31, 2016 3:46 am
Forum: NESdev
Topic: Sound synthesizer using $4011, 2a03 only
Replies: 47
Views: 11315

Re: Sound synthesizer using $4011, 2a03 only

If sampling rate is an issue, you could try the method I used to get double the normally achievable rate with DMC interrupts (8 272Hz) by sitting in the IRQ handler enough to pump out another sample right in-between two consecutive IRQ-s. It takes more CPU, but you can also spend the time after the ...
by za909
Mon Jul 11, 2016 5:03 am
Forum: Homebrew Projects
Topic: MintaBOOM - A WIP sample-based music engine for the NES
Replies: 4
Views: 6433

MintaBOOM - A WIP sample-based music engine for the NES

This is a project I've been doing on the side for a while now, and it's time to finally reveal it and show my current progress. MintaBOOM (the word "minta" [mintɒ] being the Hungarian word for "sample") is a new, work-in-progress music player, which aims to make it possible to play sample-based musi...
by za909
Mon Jun 06, 2016 7:43 am
Forum: NES Music
Topic: Noise channel notes?
Replies: 16
Views: 15838

Re: Noise channel notes?

OH silly me, I was expecting some kind of pulse-like tone similar to the "periodic" mode of the SN76489 but of course the 2A03 merely moves the taps around where as the SN76489 makes the output bit the feedback bit as well as resetting the sequence any time the Noise mode/period register receives a ...
by za909
Sun Jun 05, 2016 4:06 am
Forum: NES Music
Topic: Noise channel notes?
Replies: 16
Views: 15838

Re: Noise channel notes?

Now another interesting thing to know would be if it's possible to reliably get the same timbre every time by immediately setting the mode flag when the NES is powered on, hopefully before the LFSR receives its first clock. Losing the static would not be an issue if there's an expansion chip present...
by za909
Mon May 16, 2016 10:24 am
Forum: NES Music
Topic: $4011 writes and DPCM together
Replies: 5
Views: 4044

Re: $4011 writes and DPCM together

Yes, that's exactly what I want to do. It's not as harsh though because the DMC gets the level back to zero a lot more smoothly and not another $4011 write. I could even do this and have some control over the APU2 volume by selecting to play either $00 bytes all the time or $FF and writing $3F to $4...