Search found 2607 matches

by dougeff
Tue Dec 03, 2019 10:41 am
Forum: NESdev
Topic: Simultaneous DPCM and IRQ
Replies: 11
Views: 251

Re: Simultaneous DPCM and IRQ

There would be no way to detect when DMC is reading. It would happen multiple times a frame, and can happen any time.
by dougeff
Tue Dec 03, 2019 7:33 am
Forum: Newbie Help Center
Topic: Question about negative numbers
Replies: 8
Views: 231

Re: Question about negative numbers

About your code, calima. In display.sinc You should have reserved 2 bytes for SPR_XOFF, since you reference SPR_XOFF+1. It works without issue, because SPR_YOFF is defined immediately below it, and never used. example. SPR_XOFF: .res 2 https://github.com/clbr/neslib/blob/master/display.sinc I'm goin...
by dougeff
Mon Dec 02, 2019 11:42 am
Forum: Newbie Help Center
Topic: Question about negative numbers
Replies: 8
Views: 231

Re: Question about negative numbers

metasprites scrolling offscreen
Funny you mention that. I was just working on code that would do just that. Still thinking about it, though.

Especially, large metasprites that just POP on screen instead of smoothly entering the screen is something that bothers me.
by dougeff
Mon Dec 02, 2019 9:13 am
Forum: Newbie Help Center
Topic: Question about negative numbers
Replies: 8
Views: 231

Re: Question about negative numbers

anything from 00 to 7f is positive and 80 to FF is negative?
Yes. Because then you can use the N flag to control flow. BMI and BPL.

And FF is assumed to be -1. For example, an object just off the screen to the left. If it's moving right, eventually it's position will wrap back to 0, on screen.
by dougeff
Sat Nov 30, 2019 4:50 pm
Forum: NESdev
Topic: Background Collision
Replies: 10
Views: 331

Re: Background Collision

The background can be represented by a byte array, that represents collision boxes to what you see on screen. with 16x16 boxes, you should fit 16 wide and 15 high on a screen. 240 bytes. you only need 4 bits from X and Y each to know which block you are in. LDA Sprite_Y and #$f0 STA temp LDA Sprite_...
by dougeff
Fri Nov 29, 2019 3:04 pm
Forum: NES Hardware and Flash Equipment
Topic: Encrypted NES roms?
Replies: 31
Views: 1000

Re: Encrypted NES roms?

Another new user with 1 post.
by dougeff
Thu Nov 28, 2019 7:09 am
Forum: Newbie Help Center
Topic: reading ppu address from the second screen while scrolling (via sprite position)
Replies: 4
Views: 523

Re: reading ppu address from the second screen while scrolling (via sprite position)

X is these bits of a nametable address 0000000 00011111 Y is these bits 00000011 11100000 these bits determine which nametable 00001100 00000000 this bit is always set 00100000 00000000 so...to get X... lda AddrLo asl a asl a asl a sta Sprite_X ...and to get Y... lda AddrLo and #$e0 ;mask off X bits...
by dougeff
Tue Nov 26, 2019 9:56 am
Forum: General Stuff
Topic: NESMaker reviews?
Replies: 50
Views: 10203

Re: NESMaker reviews?

I find the transcript a bit offensive. I comes across like "I need these experts in a niche technology field to help me... and what a bunch of nerds"

Sorry. We all can't be Matt Damon.
by dougeff
Tue Nov 26, 2019 6:37 am
Forum: Newbie Help Center
Topic: Nested loops and working with X and Y
Replies: 5
Views: 216

Re: Nested loops and working with X and Y

You can use RAM addresses as counters.

LDA #5
STA counter
loop:
do stuff
DEC counter
BNE loop
by dougeff
Sun Nov 24, 2019 2:47 pm
Forum: phpBB Issues
Topic: What happened to the Nesdev phpBB theme?!?!
Replies: 74
Views: 3359

Re: What happened to the Nesdev phpBB theme?!?!

Big "culture shock" this month. nesdev changed. nintendoage is gone. Feels weird.
by dougeff
Sun Nov 24, 2019 2:45 pm
Forum: phpBB Issues
Topic: What happened to the Nesdev phpBB theme?!?!
Replies: 74
Views: 3359

Re: What happened to the Nesdev phpBB theme?!?!

I see it. board style.
by dougeff
Sun Nov 24, 2019 2:43 pm
Forum: phpBB Issues
Topic: What happened to the Nesdev phpBB theme?!?!
Replies: 74
Views: 3359

Re: What happened to the Nesdev phpBB theme?!?!

I don't see how to change to dark theme.
by dougeff
Sat Nov 23, 2019 8:31 pm
Forum: NESdev
Topic: "Multi-Directional" Scrolling - Advice?
Replies: 30
Views: 3227

Re: "Multi-Directional" Scrolling - Advice?

I keep a copy of all attribute bytes in RAM. Both nametables. That way I don't have to re-fetch / recalculate every single bit.
by dougeff
Thu Nov 21, 2019 1:51 pm
Forum: General Stuff
Topic: Intermediate level tutorials
Replies: 2
Views: 520

Re: Intermediate level tutorials

You could look at the Mario's Right Nut tutorials, now at videogamesage
by dougeff
Thu Nov 21, 2019 6:18 am
Forum: Newbie Help Center
Topic: is CNROM good for an adventure game?
Replies: 21
Views: 1055

Re: is CNROM good for an adventure game?

I don't think you can make a big game with CNROM. Only a small game. It's the PRG ROM size that will prevent you from having much level data... or boss AI.

For a larger game I would use MMC1 or MMC3.