Comment by daniel5151 | Hacker News Reader

Comment by daniel5151 | Hacker News Reader

I actually had to wrestle with this exact effect while working on wideNES [1]. By saving a screenshot of the screen at each frame alongside with it's PPUSCROLL value, it's possible to gradually build-up a map of the level as it's explored. Moreover, on subsequent playthroughs of the same level, it's possible to sync the map with the on-screen action, effectively enabling a "widescreen" mode for old NES games (with certain limitations).

Lots of games used funky scrolling mechanics, typically to create status bars, but of all the different games I tested with, TLOZ was by-far the weirdest, requiring an entire special case to get working!

I don't have any screenshots of my own, but some japanese website recently covered wideNES, posting screenshots of it working with the original Legent of Zelda.[2]

[1] http://prilik.com/blog/2018/08/24/wideNES.html

[2] https://emulog.net/fc-nes-emulator-anese-how-to-use-widenes/

*Note to mobile/metered internet users: first link contains 30MB+ of gif images, click at own risk.

I got flashbacks of 2000s with this comment

Why isn't there an HTTP request header like 'Accept-Content-Length' to limit maximum response size?

Sometimes is really expensive for the server to determine the size of the response before actually responding, e.g. some database lookups where it may not be known how many rows are returnable until the lookup is actually done.

Then there are situations where response content length is not known, such as streaming over HTTP.

Last, if a certain "Accept-Content-Length" became standard, like 8MB, developers (such as those for the ad industry) would just create javascript libraries that would download large files in 8MB chunks and sidestep it.

That was a great write-up. Thanks for sharing.

You could probably run an async loop which slices up painted frames and compares hashes of the slices to find identical slices to anchor and stitch similar frames together, still maintaining separate layers in case a better match is found later on. Something like that should solve for games like SMB.

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