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ct6502 / apple2ts

Apple II Emulator in TypeScript
Creative Commons Attribution Share Alike 4.0 International
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Does not display weird "no-delay" HGR mode, used in Prince of Persia #24

Closed ct6502 closed 11 months ago

ct6502 commented 11 months ago

Describe the bug https://forum.princed.org/viewtopic.php?f=63&t=4450 Apparently, the Apple IIe (Rev B and higher) has an undocumented graphics mode. If you set the 80COLUMN switch off, and also AN3 off, then it will only display hires graphics using 4 colors - white, black, green, purple. I guess this is used in Prince of Persia when he drinks some floating potion.

To Reproduce Steps to reproduce the behavior: 10 HGR 20 FOR A = 10 TO 79 30 HCOLOR= A / 10 40 HPLOT 0,A TO 279,A 50 NEXT A 60 PRINT "PRESS 1 OR 2 TO SWITCH COLORS" 70 GET A 80 IF A=1 THEN POKE 49164,0: POKE 49246,0: PRINT "WEIRD 80COL OFF, AN3 OFF" 90 IF A=2 THEN POKE 49164,0: POKE 49247,0: PRINT "NORMAL 80COL OFF, AN3 ON" 100 GOTO 70

Run the code and choose option 1. You still see all 6 colors.

Expected behavior Choosing option 1 should display both sets of bars in green/purple/white. Choosing option 2 should go back to the full 6 color mode.

Screenshots

bad
ct6502 commented 11 months ago

Now displays only 4 colors when in weird mode

good