Nyan Cat NES

[l_oliveira]

what mapper setup do I need to switch over to?

MMC3 is the most common mapper chip, the most powerful of the common mappers, with controls for both chr and prg banking, mirroring type and it has a scanline counter for dividing the screen...

You can't go wrong with MMC3.

[Calpis]

It would be incredibly wasteful for a demo like this to be written for MMC3 since NROM *16/8* is more than sufficient for the animation and music here! Hell, this kind of demo doesn't even need CHR-ROM, you'd have space left over if you used internal VRAM for CHR >_< Also the Mega Man games don't make extensive use of CHR bankswitching, most (MM1,MM2,MM4,MM6) use CHR-RAM so no bankswitching at all. CHR-RAM allows for much better animation (tile granularity) at the cost of CPU time and code complexity since you'll have to schedule and prioritize VRAM updates and probably implement a variable framerate.

[aliman]

by da way: today's ma 16th^^

[l_oliveira]

It would be incredibly wasteful for a demo like this to be written for MMC3 since NROM *16/8* is more than sufficient for the animation and music here! Hell, this kind of demo doesn't even need CHR-ROM, you'd have space left over if you used internal VRAM for CHR >_< Also the Mega Man games don't make extensive use of CHR bankswitching, most (MM1,MM2,MM4,MM6) use CHR-RAM so no bankswitching at all. CHR-RAM allows for much better animation (tile granularity) at the cost of CPU time and code complexity since you'll have to schedule and prioritize VRAM updates and probably implement a variable framerate.

I suggested the MMC3 because it's powerful, useful (for other projects) and is the most common mapper out there.

Last thing I was thinking of was saving resources... ;-)
More like saving hassle ... :thumbsup:

Megaman games with CHR-RAM:

MEGAMAN (UNROM)
MEGAMAN2 (MMC1 CHRAM)
MEGAMAN4 (MMC3 CHRAM)
MEGAMAN6 (MMC3 CHRAM)

Megaman Games with CHR-ROM:
MEGAMAN3 (MMC3 CHROM)
MEGAMAN5 (MMC3 CHROM)

:thumbsup:

[derekb]

I'm having a trouble doing palette cycling and was wondering if anyone could help, when I change a palette color my entire background winds up pushing itself down for some reason, my lil code snip is

[code]
lda $2002
lda #$3F
sta $2006
lda #$00
sta $2006
lda #$0F
sta $2007
RTS
[/code]

before:



after code runs:



(the boxes on top are just reference points to see whats happened)

if anyone has an idea off top of their head of what would cause this please lmk

[aliman]

is the project still going on?
just asking^^

[derekb]

yeah I'm just really really busy lately, someone on nintendoage offered me some help I just havent had time to look into it

[aliman]

yeah I'm just really really busy lately, someone on nintendoage offered me some help I just havent had time to look into it

cool^^
can't wait for the next release:thumbsup:

[derekb]

friendly update, I finally got around to working on this again, added time counter for how long you've been nyan'ing for

[derekb]

bumping because I'm still having that palette issue, writing to memory does modify the palette correctly but then my nametable winds up scrolling and I really don't get why it's happening, any help appreciated

just modifying palette with a simple

LDA #$3F
STA $2006
LDA #$00
STA $2006


LDA #$06
STA $2007

[Calpis]

Are you setting $2006 to #$0000 when you're done with it? $2006 is used by the PPU for rendering outside of Vblank.

[derekb]

you know what I am not, lemme try that and see if it fixes it, I implemented a workaround but proper code use would def be better :)

also I will be done with this rom this weekend, I added a nice counter for how long youve had nyan cat going as well as a reverse Tac Nayn mode

edit: that fixed it, thanks for correcting my oversight Calpis

[H360]

First link is DOOOOOOOOOOMED by Megaupload

[derekb]

first link was really outdated anyway, heres the latest video, I've since moved some of my CHR tiles around so that I can add the actual tac nayn graphics

[H360]

That is excellent! A real great job you have done right there.

Only suggestion I have, is to make one of the buttons hide / show the timer.

[derekb]

added the Tac Nayn sprite swap in

[derekb]

ay ay ay, calpis I'm having another palette issue, ive pmd you

basically for some reason every once in awhile my overwriting of the palette bytes will mess up and wind up placing a value in the wrong position, pardon the length of code, I was looping but wanted to make sure it was definitely not the loop

LDA #$2002
LDA #$3F
STA $2006
LDA #$00
STA $2006

; update bg palette
LDA #$0F
STA $2007
LDA #$10
STA $2007
LDA #$20
STA $2007
LDA #$30
STA $2007
LDA #$0F
STA $2007
LDA #$00
STA $2007
LDA #$10
STA $2007
LDA #$2D
STA $2007
LDA #$0F
STA $2007
LDA #$3D
STA $2007
LDA #$10
STA $2007
LDA #$30
STA $2007
LDA #$0F
STA $2007
LDA #$10
STA $2007
LDA #$20
STA $2007
LDA #$30
STA $2007


; update sprite palette
LDA #$2002
LDA #$3F
STA $2006
LDA #$10
STA $2006


LDA #$0F
STA $2007
LDA #$10
STA $2007
LDA #$20
STA $2007
LDA #$30
STA $2007
LDA #$0F
STA $2007
LDA #$00
STA $2007
LDA #$10
STA $2007
LDA #$2D
STA $2007
LDA #$0F
STA $2007
LDA #$3D
STA $2007
LDA #$10
STA $2007
LDA #$30
STA $2007
LDA #$0F
STA $2007
LDA #$10
STA $2007
LDA #$20
STA $2007
LDA #$30
STA $2007


LDA #$00
STA $2006
LDA #$00
STA $2006

for the most part this works correctly, but occasionally one of the values gets written into the wrong position and throws the entire purpose off, does anyone have any suggestions?

[derekb]

built my first cart version of the rom, works fine except for the switch to Tac Nayn, palette either glitches out like I already knew happened, or for some reason a background tile wil randomly change which doesnt happen in any of the emulators, will have to muck with it some more i guess