"Plasmine 256B intro" behind the scene

"Plasmine" is a 256B intro for Amstrad CPC.

It was released at LoveByte party on Sunday, February 11th 2024.

https://www.pouet.net/prod.php?which=96100

« Plasma. It's mine. Plasmine ! »

Backup of the archive submitted to the party right here.

Disclaimer : this article does not explain the "animation by scrolling" principle. Whoever wants to learn about it should first have look at Logon's Run - 3D meets the aging bits demo then read its making-of. Intention for today's article is clear : explanations to understand what's going on but the scroller. Source is not provided for some reasons (including : not optimized to the bones & not fully commented).

Heightmap

The screen is a heightmap - go to Wikipedia for details.

In the map above there are 256 levels on grayscale.

In Plasmine, height is a value from 2 to 32 (and 0-1 is deep blue at start).

A nice palette with coder's colors is used to refer this height :

Adding 4 heightmaps made of aztec pyramid patterns

Aztec Pyramid "Chichen-Itza". Source.

I'd better show the 4 maps on a video :

You may recall the squares from Logonite.

Yes it's exactly the same trick for animation. If we use pyramides as sprites, this would be:

The new feature compared to Logonite is : adding height value.

Let's have a close look - slowly :

Let's activate that magical scroll to animate the whole screen :

And last, let's remove those pauses to have real-time as in the released intro :

Et voilà !

Loop and add 8 times those 4 maps at random places to get Plasmine.

Overflow / Logon System

Thursday, January 29th 2024.