Nemesis generated map video is published

By Bas Wijnen

Resident (34)

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02-08-2022, 12:53

I posted a message in the pacifist run topic, but I figured this deserves to have its own topic:
I've published the video that I've been working on for a while, where I look into Nemesis to see how it was made.
Many things are the same as in the Maze of Galious, but I've also found quite a few interesting new things.

The video is here:


By Thom

Paladin (711)

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02-08-2022, 17:02

Awesome! I really like your original take on things. Very, very creative.
I especially liked the bit about the blinking stars. One question though, what do you mean by "the moais and level 6 aren't made of tiles"? I reckon you mean they are tiles, but not part of the background? Perhaps I misheard.

Looking forward to your Nemesis score attack, as I like score attacks because of "The King of Kong", a movie about people trying to get the Donkey Kong world record.

By Bas Wijnen

Resident (34)

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02-08-2022, 19:06


What I mean is that all other levels have a background plus enemies. The background is either just stars (which are probably generated with an algorithm, I didn't check) or built up from tiles of 4x4 characters. Note that I'm calling it background due to the way the screen is built up; the player can die from hitting the background characters, so it's not a background in that sense.

All levels except 3 and 6 start with a "stars" part, followed by a "tiles" part. Levels 3 and 6 have only a "stars" part, there are no (4x4 character) background tiles in those levels.

All levels have enemies, of course. Some of those enemies are also characters. You could call a cannon a 2x2 tile, but that's not what I called a tile in the video.

In level 3, the Moai statues are similar to the cannons: they are drawn on top of the background. However, the background in that level is always just stars.

In level 6, the "brain blobs" are also drawn on top of the star background, but there it's more obvious because they move.

As for the high score attempt: don't hold your breath. Wink I expect it to be very hard, and I don't know if I'll make time for it soon. But if anyone else would try it, I'd also be very interested to see it.

By Metalion

Paragon (1628)

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02-08-2022, 19:30

I don't understand the 4x4 tiles ... The VDP does not work like that, it needs 8x8 tiles.
So do you mean that they assemble 8x8 tiles from 4x4 tiles when they build a screen ?

By Briqunullus

Paladin (773)

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02-08-2022, 20:06

Tiles in this context means 4x4 characters, so 32x32 pixels. It's a way of reducing the amount of data. A full screen only needs 8x6 of those tiles, which takes only 48 bytes.

By Bas Wijnen

Resident (34)

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02-08-2022, 21:55

Yes, exactly. The tiles are 4x4 characters. That is indeed not something that the VDP supports in hardware, but it is how the map is stored in memory. For example, in level 1 if the ceiling has a "bump" in it, that's encoded in the map in the rom as tile number 7. The bump itself is 4 characters wide and two characters high. There are two more lines of 4 characters in the tile, which are empty. So that means that if there is such a "bump" the 8 characters (4x2) below it are always empty.

So when the game reads the tile number 7 from the internal map, it looks up the definition for that tile (which is also in the ROM) and it writes 4x4 characters to screen. (Well, technically it writes 1x4 characters whenever a new part of the tile appears on the right edge of the screen; after that, it just copies it over without looking it up again.)

By Briqunullus

Paladin (773)

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03-08-2022, 10:48

Bas, the mechanism is complety clear. It's just the word 'tile' that confused Metalion. Usually, tile is used instead of character. Because when it represents graphical data, it's not a character, is it?

So when Metalion says he expects 8x8 tiles, he means 8x8 pixels. And he thought you meant 4x4 pixels and that would be really strange from a vdp perspective. That's all.

By wimpie3

Champion (438)

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03-08-2022, 12:18

Very very informative! Thanks!