How To

Animate background tiles

TheSailor 2023-02-12 04:34

I've been looking around the documents and the forum but don't see it mentioned. So is it not possible to animate a background tile?

GAMELEGEND 2023-02-12 05:13

It is possible

I don't know if there is any other way to do it but the way I did it to make this conveyer belt I used the characters 1,2, and 3 and had the graphics for the conveyer belt in 4,5, and 6 and then I copied the data from 4,5, and 6 to 1,2, and 3
and because the character number for the cells I set are 1,2, and 3 you see a moving conveyer belt.

Was8bit has released multiple very good examples just type animated in the search bar.

Roboier.nx | Open in app

2023-02-12 05:13

nathanielbabiak 2023-02-12 05:35 (Edited)

Yes, it's not terrible.

To get up-to-speed, read the manual section "Advanced Topics", but only "Memory Map" and "Character data".

To animate a background tile, you need to:

Create a sequence of animation characters in the Gfx designer and save it to a ROM.
Set a background cell to an unused character (in RAM).
Every frame, copy 16 bytes of data from the Gfx character (in ROM) into the character data (in RAM).

For example, suppose you have a 4-character animation saved in ROM(2) in characters 8, 9, 10, and 11, and you want to animate it into character data (RAM) in character 32...

ON VBL CALL MY_ANIM
SUB MY_ANIM
  COPY ROM(2)+16*(8+(TIMER MOD 4)), $8000+16*32
END SUB

TheSailor 2023-02-12 05:49

Thanks guys. Appreciate you breaking it down for me. I'll play with the code examples you've given. From what I can see @nathanielbabiak is closer to what I was after but having the conveyor stage on my game use tiles instead of sprites would help with the collision checking I think. So that's also helpful @GAMELEGEND

TheSailor 2023-02-14 16:04

That code snippet you gave me doesn't seem to work...

Animation characters saved in ROM 2
(112,113,114)

BG saved in ROM 7
Empty character used in background is character 97

The code snippet using your framework...
COPY ROM(2)+16*(112+(TIMER MOD 3)), $8000+16*97

McPepic 2023-02-14 18:26

@TheSailor
Try:
COPY ROM(2)+16*(112+(TIMER MOD 3)), 16 TO $8000+16*97

nathanielbabiak 2023-02-14 23:05

Sorry, I forgot the "16 TO" that needs to sneak its way into the COPY instruction just after the comma...

TheSailor 2023-02-15 06:31

Yeah that makes sense now. You have to copy the 16 bits to the character specified. That worked. Thanks! Now to get the crate tiles moving along the conveyor 🤣

TheSailor 2023-02-15 13:50

Okay I threw in the towel and changed the crates back to full sprites. 🙄

Timo 2023-02-16 10:30

Yes, if you want to move objects pixel by pixel, then sprites are the way to go. On the BG you can only change things cell based.

TheSailor 2023-02-16 10:54

I definitely used the hard way to find that out 🤣