nesdev.org

ROM link: http://files.slembcke.net/temp/InterglacticTransmissing.nes.zip http://files.slembcke.net/upshot/upshot_qPk8in7Z.png http://files.slembcke.net/upshot/upshot_Gn7N88cc.png First actual NES game for me (I've only tinkered...)! I convinced some people at the global game jam to work on the NES....

RTS Chaining, I think they meant this: http://wiki.nesdev.com/w/index.php/RTS_Trick I've was experimenting with this stuff yesterday and had pretty good luck. Other than it being non-obvious, it's pretty easy to do. Basically just writing a 2 byte command token instead of just one. You can easily av...

That's pretty clever. I've been musing about similar stack abuses for tail call hacking. In hindsight now it seems perfectly clear, push the destination to the stack and return. Thanks.

I've had a bit of trouble getting it to build on OS X too, though I should have written down what the problem was. I did get it to build on Linux just fine, though I did it in /tmp on my really slow netbook. Let the battery run dead on it (derp) before I actually got a chance to try it and haven't t...

For posterity, I did get a full ~80 cycle divide working here:
viewtopic.php?f=2&t=16933

Not really sure if it's worth it at 80 cycles except maybe when used from C code that's slow anyway.

Related thread with a much faster 12 bit divide: http://forums.nesdev.com/viewtopic.php?f=2&t=16911 So it was nagging at me that there must be a way to get a full 16 bit divide** by 240 using the trick I did in the last thread. (The idea is basically the same as this: http://blog.jgc.org/2012/03...

This is how it would work with 16-bit coordinates: Not sure how that is supposed to work. It just subtracts 240 from the upper byte of the dividend? This ruby snippet works for all valid quotient/remainders, but needs a 16 bit shift and add. def div240_16(n) q = n >> 8 r = n & 0xFF r += q << 4 ...

Yeah, storing the scroll twice did occur to me as (probably) being more efficient, but as you say, not very DRY. After sleeping on it, I think it's possible to get a full 16 bit divide with a little more work. Since the overflow happens on a multiple of 16, I think you can just add the upper nibble ...

I'm having way more fun doing 6502 asm again rather than actually making a game. :p This seemed useful enough to share, a fast divide by 240 with modulo. Allows you to store scroll offsets in > 8 bits, and quickly get the scroll value and starting page. 12 bits gives you lots of room to work with. ;...

Now with split scrolling!


Fixed the jerky scrolling by switching to NMIs as well. I had forgotten how much fun 6502 assembly was even if it's not very practical in 2018. :p

Started prototyping my boat sprites. Pre-computed sprites with flipping and palette swapping is going to be overly satisfactory I think: http://files.slembcke.net/temp/FairwindsBoat.png (The red/green channels are going to be mapped to the two bitplanes.) 64 rotations in only 32 character table slot...

Goonies and Hello Kitty certainly caught my eye on a second look. Who would risk selling a homebrew game based on somebody else's IP. I wonder if the store realizes what they are selling. It's just a little locally owned game store, so I'm kinda guessing not.

but it looked like you had a wind mechanic that complements the player avatar changing directions Nah, it was hard coded in the original. It was a game jam game, so I never got far enough to make the wind into a mechanic. Huh... i've never seen those titles before. and they're cheap. Wait, did you ...

At first I thought it was neat that a local games shop was selling homebrew games. When I started Googling for the names, a lot of them seem to be Japanese only. Are these pirate carts or something?

After sleeping on it. I can only get 2 sub-frames using palette swaps. True, but pixels on the NES are also half the size in each direction of pixels on the PICO-8 Nah, wasn't going for a 1:1 remake. I was looking for an interesting, but doable project. No need to add extra constraints. ;) The video...