williams-et-al-1983-apple-ii-computer-graphics

PEEK statement, use, 13, 21-23, 59, 161flictu resLow- Res, 44-46preserving of, 53-63Plot, hatching of, 46-48PLOT command, use, 21, 46, 47, 48Plotting, functional, 1 28-1 29PO KE command, use, 13, 21, 23-24, 25,99, 108PO KE function, 34, 37, 99, 138, 149, 151Power light, 4, 6Pre-calculation, 149-1 51Pre-shifting, 141-1 54PRINT PEEK command, 22, 59"PRINT USR(C) " statement, 27-28Prompt characters, 14RAM, 4, 5altering of bytes, 14, 15erasure from, 5READ command, 51, 99, 108ROM, 4, 5, 13, 14ROT, use, 108-1 09, 110SCALE, setting of, 106, 108Scaling factor (SCL) , 122, 127Scan, Low- Res, 54, 55SCL, see Scaling factorScreenclearing of, 16, 17shape generation on, 101SHAPE, use, 99Shape( s)byte-move, 154creating and placing of, 100, 1 09-1 15designing and digitizing of, 100, 116drawing of, 100-1 03, 105finding of, 105plotting of, 99UFO's, 103-1 04use of DRAW, 105-1 06use of ROT, 108-1 09, 110use of XDRAW, 115-1 16Shape commands, 135Shape table, 104-1 05, 111, 123, 127,158, 168enteringand saving, 1 06-1 08, 1 23-1 24location of, 105-1 06, 111shape drawing with, 109, 110Shifting, 151-1 54SH LOAD command, use, 108, 116Soft switches, 33-34add resses, 35ffor display control, 36-3 7toggling, 33, 34Sound assembly, 61-62Subtraction, 168-1 72Tape, saying of, 107-1 08Text, placing of, 112-1 13, 121Text modes, 31-32, 35fmemory map, 40-4 1use, 39-40, 41-42, 43Text screens, 31, 3 2 ·Toggle switches, 33, 33fTrigonometry, circle drawing with, 131UFO's, drawing of, 103-1 04USR statement, use, 26-29, 31Vector(s) , 135· digitizing of, 109shape drawing with, 100, 103, 135encoding of, 101-103Vector codes, 101 fplacing of, 102Vertical add ress, 42Vertical blanking, 155Vertical Blanking Location (VBL) , 155VLIN command, use, 46, 47f, 47, 48Voltage, testing for, 4XDRAW command, 135, 152, 153, 154,155, H9use, 11 5-1 1 6188