Reverse engineering of TCB Star Wars Scroller

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uko
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Reverse engineering of TCB Star Wars Scroller

Post by uko »

Yes, I know, I'm quite obsessed with Star Wars Scrollers... :lol:

https://github.com/Uko-TAL/TCB-Star-War ... ngineering

Enjoy !
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Cyprian
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Re: Reverse engineering of TCB Star Wars Scroller

Post by Cyprian »

nice article, I will read tomorrow

Just to clarify, do you mean this screen?
https://youtu.be/5pRelt_CPVk?t=3851
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uko
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Re: Reverse engineering of TCB Star Wars Scroller

Post by uko »

Yes that's this one !
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Re: Reverse engineering of TCB Star Wars Scroller

Post by dhedberg »

Revealing the secrets of the Swedish legends, huh? Thanks for the write-up. Enjoyed reading it!
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Re: Reverse engineering of TCB Star Wars Scroller

Post by uko »

Hi Daniel, thanks for your feedback !
It would have been funny to title this post this way ! Secrets of Swedish legends revealed! :lol:
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Re: Reverse engineering of TCB Star Wars Scroller

Post by mlynn1974 »

Brilliant screen and great analysis.

The stars are 2 bitplanes, the Union logo is 1 bitplane but the scroller is also 2 bitplanes (1 colour where the rainbow rasters are mapped, 2 colours for the font border and 1 black colour) but are the logo and the stars mixed every frame? That's a lot of or-ing.

I wonder how TCB designed or wrote the sprite waveforms? I was always impressed with that.
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Re: Reverse engineering of TCB Star Wars Scroller

Post by terence »

mlynn1974 wrote: Thu Sep 22, 2022 7:48 pm I wonder how TCB designed or wrote the sprite waveforms? I was always impressed with that.
an easy way is to read X and Y at different speeds. this makes fun curves from already nice maths curves
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Re: Reverse engineering of TCB Star Wars Scroller

Post by uko »

mlynn1974 wrote: Thu Sep 22, 2022 7:48 pm Brilliant screen and great analysis.
Thanks to TCB and thanks for my analysis ! :wink:
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Re: Reverse engineering of TCB Star Wars Scroller

Post by troed »

mlynn1974 wrote: Thu Sep 22, 2022 7:48 pm The stars are 2 bitplanes, the Union logo is 1 bitplane but the scroller is also 2 bitplanes (1 colour where the rainbow rasters are mapped, 2 colours for the font border and 1 black colour) but are the logo and the stars mixed every frame? That's a lot of or-ing.
Screenshot from 2022-09-23 09-14-02.png
Screenshot from 2022-09-23 09-14-35.png
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thomas3
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Re: Reverse engineering of TCB Star Wars Scroller

Post by thomas3 »

That font looks 3bpl to me :)
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troed
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Re: Reverse engineering of TCB Star Wars Scroller

Post by troed »

Yeah it's a 3bpl move.w (16 pix y-dist, looks 8 pix-flickering due to offset in buffering) scroll on top of 1bpl logo. Stars or:d on top of everything (no and:ing).

Well, that's my guess from just looking at it anyway :D Never disassembled another group's code.
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thomas3
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Re: Reverse engineering of TCB Star Wars Scroller

Post by thomas3 »

Yeah I thought the same. Some smart palette choices could probably mitigate the need for and:ing, although maybe they didn't even bother with that... :)
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Re: Reverse engineering of TCB Star Wars Scroller

Post by Ray »

mlynn1974 wrote: Thu Sep 22, 2022 7:48 pm
I wonder how TCB designed or wrote the sprite waveforms? I was always impressed with that.
My guess is, they recorded mouse movements. So its kinda „painted“ 😉
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