Propeller Backpack TV Overlay with User-defined Character Glyphs

[Phil Pilgrim (PhiPi)]

Attached is an update to the original Prop Backpack TV overlay object, which allows users to define their own character glyphs (bitmaps). Unlike my initial attempt at this capacity, this version does not require mapping the entire font into RAM. Instead, 16-character blocks can be mapped, starting with $F0-$FF and working downwards. This is effected by placing the RAM blocks at the end of memory xxxx - $7FFF, so that they are contiguous with the ROM font, which begins at $8000. By changing the effective font address to the beginning of the RAM section and translating characters written into the overlay's window buffers by the amount of the offset, the font can bridge both RAM and ROM without exacting additional timing requirements on the realtime video overlay code.

-Phil

[Duane Degn]

Thanks Phil.

I'm anxious to try this.· Now where did I put my Prop Backpack (aka HoBo)?

Duane

[Phil Pilgrim (PhiPi)]

Duane Degn said...
... (aka HoBo)

Hee hee! Thanks for remembering!

All,

I've submitted the package to the OBEX, but it seems either to be stuck in limbo waiting for approval, or was rejected due to missing license boilerplate (which is not missing, BTW). The messages I got back are a bit ambiguous as to the reason for the delay or rejection.

-Phil

[Duane Degn]

I finally found my Propeller Backpack.

This is great.· I'm got little guys waving at me across the top of the screen.

This has so much potential!

Thanks Phil!

The demo appears to use 2,654 longs.· I'm guessing this doesn't include the custom characters.· Are there any other resources using memory (besides normal stack stuff)?

I know some of the video drives look like they have plenty of free memory but if your program is too long then either your program doesn't work or you get weird stuff on the screen.

I'm hoping there is as much free memory (or nearly so) as F8 is telling me there is.

Again, Phil·thank you very for such a useful object.

Duane