Cooking with gas!!!

Yah! A few more frustrating bugs squashed and the tilemap layers are now all-but-done. They've been tweaked for proper centering, pixel-perfect alignment between layers, and it's all - finally - looking good to implement the scrolling next.

Title screen, which uses both tile layers for the logo

The map screen is back!

Part of the scrolling implementation is adjusting the visible areas at top and bottom of the background layer. That's trivial, because I use a pair of black opaque sprites to mask the not-visible extents.

I should note that the actual code for updating the colour and video RAM areas are far from optimal at the moment, and I plan to fix that at some point. In order to facilitate getting everything right, I reverted to the original video RAM layout and went through the same steps as the original code in calculating RAM addresses from row and column pairs etc. In my Neo Geo layer, I effectively have to reverse that calculation again. It would be far more efficient to bypass the RAM altogether, and I'll look at doing exactly that at some point.

My previous implementation of the scrolling map hasn't gone to waste either; I'll have to use some of that mechanism in the new implementation. I'm actually hoping I can knock out scrolling in one more session at the keyboard.

I think I've just jinxed myself now...