Apple II Lores Waterfall Transparency Demo

For now you can get the disk image here: waterfall.dsk (140k) 20 September 2018

The souce code can be found on github in the repository in the vaporlock/waterfall directory.


The actual hardware capture looks a bit worse than it should because I had the page flipping order a bit off but didn't catch it until I left for the weekend.


Maybe at some point.

Random devel notes

3 August 2018

The graphics didn't turn out as good as I'd hoped.

There are two images, one on lores page1 and one on page2. The waterfall effect is done by switching pages per-scanline, but only over the water part of the picture. The sprite is only drawn on the background image. Erasing it takes up over half of the VBLANK.

Ran into a frustrating cycle-counting problem when trying to use a jump table, which turned out to be the JMP (IND) taking 6 cycles on 65c02 and 5 cycles on 6502. I ended up using PHA/RTS to do this instead.

My Mockingboard still has the frustrating glitch issue, ruining the white noise waterfall sound effect.

20 September 2018

Updated with my new vapor lock code and it seems to behave a lot better with getting the waterfall to appear properly.

Back to my Apple2 page