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View topic - Can the Master system draw one tile image on top of the other?

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  • Joined: 14 May 2017
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Can the Master system draw one tile image on top of the other?
Post Posted: Sun May 14, 2017 1:31 am
Hi everyone. I thought I read somewhere that the SMS can blit (draw) twice into a single tile location in the background (of course using one of the two 16 color palettes).

Can anyone confirm if this is true? I've been scouring the internet and can't find where I had read this. Also, if this is true, would it be possible to do things like draw the first tile image flipped horizontally, and the second one not flipped horizontally, but flipped vertically?

Thank's very much for your help.
-Mike
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Post Posted: Sun May 14, 2017 3:08 am
The SMS can't blit anything. 1 tile is set per 8x8 region of the screen, and background tiles can't overlap.
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SMS drawing two tile images in one tile location on screen.
Post Posted: Sun May 14, 2017 5:18 pm
Last edited by Bitbeam on Sun May 14, 2017 7:29 pm; edited 1 time in total
ccovell wrote
The SMS can't blit anything. 1 tile is set per 8x8 region of the screen, and background tiles can't overlap.


Sorry if I misused the word "blit", but I think you're mistaken about whether or not the SMS can draw two tile images in the same spot.

Please see this thread: /forums/9224-WhyDoesntGoldenAxeFlicker

And any longplay of Golden Axe for the SMS

This tells me either the SMS can do it, or a custom chip in some cartridge can allow the SMS to do it.

Am I somehow mistaken?
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Post Posted: Sun May 14, 2017 6:27 pm
Nope, it's all software.
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SMS drawing twice in the same tile space.
Post Posted: Sun May 14, 2017 6:45 pm
Maxim wrote
Nope, it's all software.


Excellent. I take it to mean its possible (clearly based on Golden Axe) and they didn't even need to add a special chip to the SMS.

Do you know if there's any documentation or example for how this was done, code-wise?

thanks.
-Mike
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Post Posted: Sun May 14, 2017 7:16 pm
Just draw into tile data and upload it to video memory. Golden Axe updates the pixels around the characters (I think) but that means they have to move in 8 pixel increments. Lemmings does something a lot more clever...
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Post Posted: Sun May 14, 2017 7:41 pm
thanks for the info and verification.
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Post Posted: Mon May 15, 2017 1:19 am
Maxim wrote
Lemmings does something a lot more clever...

I've always been curious about that as a kid. Playing Lemmings on my Master System was unbelievable. How did it look and run like a PC game. Where was the flicker?

I'd love to see someone do a teardown on this version someday.
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