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Cart #22059 | 2016-06-01 | Code ▽ | Embed ▽ | License: CC4-BY-NC-SA

Dunno what causes this weird effect to happen.
Wait about half a minute or so and look at the plane and watch the wall background closely and how things move.

Note that I didn't employ any parallaxing and the only sprites are the plane and the shadows. Yet, at times, especially when it speeds up, things in the background (floor/wall and table/images) seems to be moving at different speeds and sometimes even in different directions. Weird optical illusion/bug in p8. Or I may just be tired and seeing things.



Yeah, I'm seeing that too :o


So yeah. There's certain effect I had not mentioned (look at the table) to check for me just suggesting other people. If anyone sees it too (happens few minutes after this was running), I'll be 100% sure it's not just me suggesting other people.

Anyway, I suspect (if it really happen) either of the following:

  • Optical illusion. Which one, I am not sure (if I'm lucky and it's a new one I reserve the name "Scandalous Fake Parallax Illusion")
  • Bug in Pico that makes it not render stuff correctly.

You can inspect cart's code to see that no parallax is going on and background is 100% static (like in most NES games).



Nothing too complex. If you have a pattern that repeats every 8 pixels, and it's also "moving" 8 pixels every frame, it will look like it's being drawn in the exact same position/not moving. Tweak the speed a little up or down, and it will appear to be moving right or left by a pixel each frame.

The background elements have patterns in them with differing repeat periods, so they appear to move at different rates. If their periods have a common multiple, there will be times that their apparent motion will line up.


Either way, I intend to keep this effect in. Just wanted to share it and see if anyone else sees this as well.


Darkhog, I am liking the paper airplane sim. It brings back some great old memories.



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