How Wario's Woods works?

Discuss technical or other issues relating to programming the Nintendo Entertainment System, Famicom, or compatible systems.

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kikutano
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How Wario's Woods works?

Post by kikutano » Mon Aug 24, 2020 1:34 am

Hello to everyone! I was playing Wario's Wood on Nes and I can't understand how many things are made.

https://www.youtube.com/watch?v=HWBPkXBuvVY

As you can see in this video the entire background and Meta Tiles are constantly animated how can they do that? Another thing that I don't understand is how can the player get an entire column and translate it left and right. Is the background tiles "translated" as sprites and then translated again in background?

This game is really amazing and break a lot of Nes limits. What do you think?

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Gilbert
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Re: How Wario's Woods works?

Post by Gilbert » Mon Aug 24, 2020 2:09 am

I don't know what mapper Wario Woods used (but from its late release date I think it wouldn't be a primitive one, probably at least MMC3) but if this mapper supports bank switching CHR ROM (read: most "non-simple" mappers) the animated effect is just "free and easy" on the Famicom. For systems that use video RAM to hold graphics pattens (read: most systems) you need to either use dynamic tiles (i.e. rewriting the pattern table continuously) or rewrite the tile map continuously to use different tiles to archive the animation effect.

For the column moving part I think it's just rewriting the tile map. I think only one column is moved each time so the update is probably not that demanding.

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aa-dav
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Re: How Wario's Woods works?

Post by aa-dav » Mon Aug 24, 2020 5:23 am

kikutano wrote:
Mon Aug 24, 2020 1:34 am
Meta Tiles are constantly animated how can they do that?
This is usual trick - it uses mapper MMC3 and changes half of the CHR data (tiles images) of the background to animate these tiles.
Is the background tiles "translated" as sprites and then translated again in background?
And... no (!). In this case it uses unusual trick. It's CHR data contains bombs and mosters in every possible shifts, so scrolling of picked column is made by replacing 4 or 5 column of tiles with several variants of shifted tiles.
In the game last half of CHR data for background contains 4 possible entities: 2 bombs and 2 monsters in every possible shifts and switches it for animations periodically.
Image
There is one exception: first title screen. It really uses sprites for bombs and monsters.

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kikutano
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Re: How Wario's Woods works?

Post by kikutano » Mon Aug 24, 2020 6:16 am

Thanks for the replies! I was watching the PPU Debugger with Mesen emulator and this game made a lot of interesting tricks on Nes.

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