The idea is to redefine all those chars to create sprites, as in https://forum.defence-force.org/viewtopic.php?t=2449
Problem is that I don't have a clue of
- how the charset is encoded (at 0xb900 after being copied from rom to ram)
- how to reference those chars when displaying
- on the screen memory : is a single "shape" 3x2 pix ? So 160 bytes (eg. starting at 0xBB80) will represent 2 lines of 80 shapes ?
I'm in the haze )
Tried several books from defense-force library, and articles from osdk web site, I still don't get it.
Eg. from https://www.defence-force.org/computing ... /index.htm
Code: Select all
Coding of alternate charset 01 02 04 08 16 64 If you want to draw a character with the top-left ,middle-right, and bottom-left blocs activated, you have to display the character with the ASCII value of: 32 (Characters before 'space' are attributes) +01+08+16. Perhaps you notice that the last value was 64 instead of 32 ? We need to force the 5th bit to ONE, so we're sure to never have to display an attribute. All of that is a little bit tricky, and hard to explain, but it's not so important to know it since nobody uses this mode :)