Search found 216 matches

by za909
Thu May 16, 2019 3:21 am
Forum: Newbie Help Center
Topic: Techniques to detect scanline
Replies: 14
Views: 11914

Re: Techniques to detect scanline

Some time ago I proposed the idea of polling the noise channel's length counter state bit in $4015 to wait for approximately half of the visible scalines to be drawn (depends on the timing difference between the CPU and the APU frame sequencer). It's not the most useful thing in the world and I neve...
by za909
Wed May 15, 2019 1:14 am
Forum: NESdev
Topic: Efficient technique for improving DMC timing accuracy
Replies: 20
Views: 15589

Re: Efficient technique for improving DMC timing accuracy

This is some great news! If this technique is demonstrated to produce those results, I might just have to go back and re-write my IRQ handler. For now, I could get away with the 2-3 scanlines of jitter (somehow I could only get this work with rate $C) by designing my graphics such that solid colors ...
by za909
Fri May 10, 2019 1:11 am
Forum: NESdev
Topic: 4-bit Samples on the Pulse Channels
Replies: 4
Views: 6209

Re: 4-bit Samples on the Pulse Channels

I think if you write to $4003/$4007 the phase will reset, so doing this "constantly" will ensure a DC output, leading to the effect you want. I'm not sure of the phase, either duty cycles %00, %01, %10 will work and %11 won't work, or it's the oposite. This is actually the only difference between d...
by za909
Thu May 09, 2019 5:33 am
Forum: NESdev
Topic: 4-bit Samples on the Pulse Channels
Replies: 4
Views: 6209

4-bit Samples on the Pulse Channels

Hi there, I've had yet another idea to cram more into my DMC IRQ-based PCM music player, since a scheduler meant to handle game logic tasks during a wait inside the IRQ handler proved to be of very little added efficiency to a game. Since I need to wait more than 100 cycles / IRQ, I thought I could ...
by za909
Sun Apr 21, 2019 2:22 am
Forum: NESdev
Topic: Why not mapper 11 or 66 ?
Replies: 53
Views: 28547

Re: Why not mapper 11 or 66 ?

I can agree that UxROM is very attactive to jump to after messing around with NROM. If you look at it, some of the early "great games" of the system used it like Castlevania or Mega Man. It's much easier to get into at first, since you don't have to worry about any kind of volatile trampoline routin...
by za909
Sun Apr 14, 2019 4:40 am
Forum: Newbie Help Center
Topic: Increasing x_pos by 4, but sprite can move outside of grid?
Replies: 12
Views: 7879

Re: Increasing x_pos by 4, but sprite can move outside of gr

If you want easy rectangular hitboxes, try to limit the fastest speed anything can go at to be less than the smallest length of any hitbox's side. Otherwise, like mentioned before, objects may pass through other objects if they go too fast (in one frame the object is to the left of something, and in...
by za909
Fri Apr 12, 2019 11:31 am
Forum: NESdev
Topic: How many times can the NES change scrolling in a frame?
Replies: 57
Views: 33966

Re: How many times can the NES change scrolling in a frame?

Something that always gets on my nerves is when people see raster effects on the SNES, they think it's either "mode 7" or the "FX chip". There seems to be this false myth out there that "the SNES can't do anything special without outside help", but then again, I think the opposite is also true wher...
by za909
Thu Apr 11, 2019 11:39 pm
Forum: NESdev
Topic: Namespacing symbols used by an ASM6 library
Replies: 18
Views: 23949

Re: Namespacing symbols used by an ASM6 library

Since my ASM6 projects are rarely that big, I tend not to use any kind of scope prefix if the variables or constants are unique enough. Why would I prefix a musical note constant if I know there really is no reason to name anything else in the project a "D_2" or anything similar. So my custom music ...
by za909
Wed Apr 10, 2019 1:57 am
Forum: NES Music
Topic: Best soundtrack?
Replies: 57
Views: 44361

Re: Best soundtrack?

It's hard, because my "technically superior, therefore, better" glasses are blinding me to a lot of well-composed but technically not as interesting soundtracks. I think Megaman 2 is a great example of that. Great tunes, but kind of generic instrumentation. Then again, it's kind of unfair to compare...
by za909
Wed Apr 10, 2019 1:45 am
Forum: Other Retro Dev
Topic: PC Engine specifics
Replies: 21
Views: 25732

Re: PC Engine specifics

It would make sense though, because there is probably some kind of internal "buffer register" to hold some of the operands, as there are 6 bytes that need to be kept track of. My guess is that the source, destination and length are likely stored in a combination of these buffers and X & Y, and then ...
by za909
Tue Apr 09, 2019 12:02 am
Forum: NESdev
Topic: How many times can the NES change scrolling in a frame?
Replies: 57
Views: 33966

Re: How many times can the NES change scrolling in a frame?

Now instead of a terminology / semantics war, I'd personally like to think about doing an Atari 2600-like manual, CPU-driven image display. Using the scroll registers would be the way to draw the colours you want. It wouldn't provide anything terribly practical because of how fast the PPU pixel cloc...
by za909
Mon Apr 08, 2019 2:59 am
Forum: General Stuff
Topic: What have you learnt most from programming in assembly?
Replies: 28
Views: 22603

Re: What have you learnt most from programming in assembly?

I'd had no programming knowledge other than a few classes of "Comenius Logo" or whatever it was called, before I started learning 6502 assembly. I have to say that the first thing people notice in my higher-level code is that it's absolutely filled with comments to the point that almost every line h...
by za909
Thu Apr 04, 2019 12:01 am
Forum: General Stuff
Topic: Inferiority complex?
Replies: 10
Views: 7109

Inferiority complex?

Hi all, I have just read through this post , and it made me question my behavior in the process. When I was relatively new to the forums I had an immense inferiority complex that has somewhat disappeared, although I still see myself as someone who doesn't quite belong due to my non-existent programm...
by za909
Tue Mar 26, 2019 12:41 am
Forum: Other Retro Dev
Topic: PC Engine specifics
Replies: 21
Views: 25732

Re: PC Engine specifics

I have since fixed most of the issues + added a bit of code to manually force instructions for which the operand would fall within the PCE's zero page to be looked up again and have their operand truncated to its low 8 bits before being emitted to the output file. I'll have to put a bit more time in...
by za909
Sat Mar 23, 2019 2:11 am
Forum: NES Music
Topic: APU: volume and... envelope? ^^;;;
Replies: 35
Views: 28901

Re: APU: volume and... envelope? ^^;;;

I think there is still some use for the linear counter, even in an all-software environment because it lets you do something that software would normally be unable to do, which is to play those very short triangle bursts. Since my sound engine rewrites all three triangle registers every frame I have...