Graphics Glitch (Totem Pole Effect)

[KevKelley]

Every once and a while I screw something up in my code resulting in a graphical glitch where it looks like all the sprites are kind of stacked together, kind of like a totem pole. I had two questions.

 

One, what exactly causes this, and two, what may be the quickest way to cause this.

 

Usually I stumble across this by leaving something out while typing and I correct it quickly so I can't remember when this usually happens which is why I ask.

[+Gemintronic]

Without seeing the code that reproduces this I can only guess.  Usually for me it's a matter of positioning the sprite waaaay down off the screen.  With Al_Nafuurs sprite data sharing technique this also happens to player0 if you don't pad the top of the sprite data with a row of zeros.

[Trip2018]

I know if you overflow ram with pfres you can sometimes get a flash of it on screen.

[KevKelley]

Next time it happens I'll be sure to save it.

[KevKelley]

So playing around with Superchip and Multisprite I had this occur.  Thought this was really cool specifically because it seemed to take the playfield data and it kind of matched up nicely.  If I could figure out the specifics this could be useful for something.  I imagine this is because of how the playfield data is stored in the multisprite kernel as normally when I have had this happen it seems to cycle the various sprite data.

[+Gemintronic]

As far as I know it's continuing to draw the sprite with whatever is in ROM - code, sprites and data of all sorts.  I've used it for a Yars Revenge effect in Dead of Knight.

 

As you add/change code the graphics will shift.  So, it might be hard to reliably use it for more than a long, static-y column of jumble.

[KevKelley]

44 minutes ago, Gemintronic said:

As far as I know it's continuing to draw the sprite with whatever is in ROM - code, sprites and data of all sorts.  I've used it for a Yars Revenge effect in Dead of Knight.

 

As you add/change code the graphics will shift.  So, it might be hard to reliably use it for more than a long, static-y column of jumble.

Usually I always see a string of sprites and jumbled mess but this was the first time it was nice and clean and organized. Perhaps that had to do with how I setup the playfield to begin with so it just looked really nice but I suppose you are right. But maybe under a really specific situation could this be of use. Lol

Just reading about using the sprite data for multiple sprites and then experiencing this made me rethink this post.