Progress is on-path!

Domogram was one of the more complicated ground-based objects and I must say the implementation went pretty smoothly. It's the object that seemingly 'follows' paths.

The circling Domograms on Level 7

Of course it's all pre-canned routes programmed via a list of vectors comprising dX,dY and length components. The map data encodes a single byte for the dX,dY pair, which is an index into a table of actual values for the pair. Each Domogram can have up to 64 bytes (32 vectors) programmed into a circular buffer that can hold path data for up to 12 Domograms on-screen.

Up next, Derota. That will incidentally finish off the ground-based objects for Area 2.

UPDATE: Derota finished!

UPDATE #2: Garu Barra, Garu Derota and another Grobda variant fnished, rounding out Areas 1-4 for ground-based objects.

Garu Derota, before being destroyed

The Garu (big) objects comprise a 2x2-tile sprite overlaid with a 1x1-tile sprite in the centre. When the centre sprite is hit, it is removed to reveal the 'destroyed' 2x2-tile sprite. Obviously this requires the centre sprite to have display priority over the larger... fortunately the sprite priorities of the arcade board and the Neo Geo are compatible - it would have been a minor inconvenience to (programmatically) reverse the orders in the code, but not insurmountable.

The next Grobda to appear in the game (Area 3) was one of the 'duplicated' variants. Implementing the Garu objects had given me a hint as to why this could be (indicated by a common graphics glitch before transcoding was complete), and I quickly confirmed it. Although the behaviour of the two Grobda is exactly the same - in this case moving forward when targeted in the crosshairs - one of the Grobda leaves a crater when destroyed, the other simply disappears. The latter, as it turns out, appears on water (where obviously it sinks when destroyed).

Another example of something that can easily be missed in a static analysis.

One gound-based object (technically, 16 objects) that I haven't implemented yet in Area 4 is the Andor Genesis (mothership). I figured I'd leave that until the last of the ground-based objects.

Although the ground-based objects do (visibly) 'fire' back at the Solvalou (and the animation is complete), the bullet objects have not been implemented. It's difficult to tell, but some of them appear to be firing a crap-tonne of bullets, and I'm not sure there's no bugs in that part of the code. So I'm thinking it might be time to implement the bullets - even if they remain harmless atm - just to get an idea of whether the firing logic is correct.

Oh and I fixed the background layer display of tiles from the 2nd bank.

The Nazca Lines are now rendered correctly (again)