4] Hires Video modification for Amiga Imagine From James R. Walker

***Note: The following explains how to modify the actual executable file of Imagine. Do this at your own risk! If you have any problems or end up trashing your copy of the program it is your own fault. It is highly recommended that you make a backup copy of the program before you mess with it.

Ok, here's how it works... (If you don't have an Amiga, don't do this!)

Get a filezapper type program. (NewZap DPU FileZap Hex etc...)

Look up your version of Imagine on the chart below.

Edit the executable at the bytes indicated in the chart. The block #s and byte #s are shown in decimal. The hex numbers in parenthesis are the hex versions of the block numbers. The bytes to modify are, of course, in hex. Replace the resolution you find there with the resolution you want. Then save the new file. (I don't have to remind you to keep a backup of Imagine on hand!)

Notice that Imagine automaticly doubles the vertical resolution for use in interlace mode. So, if you want vertical resolution of 462 then you must tell it to give you 231. (231 = 00E7 in hex)

   Imagine Version # Horizontal                   Vertical

  FP       1.1     Block 393 ($189)             Block 83 ($053)
                   Bytes 220 & 221              Bytes 162 & 163
                   From  02    80               From  00    C8
         (Example: To    02    BC = 700 in dec)(To    00    E7 = 231 dec)

  FP       2.0     Block 497 ($1F1)             Block 95 ($05F)
                   Bytes 328 & 329              Bytes 250 & 251
                   From  02    80               From  00    C8

  INT PAL  2.0     Block 500 ($1F4)             Block 94 ($05E)
                   Bytes 124 & 125              Bytes 42 & 43
                   From  02   80                From  01   00

  FP  PAL  2.0     Block 497 ($1F1)             Block 95 ($05F)
                   Bytes 388 & 389              Bytes 244 & 245
                   From  02    80               From  01   0

  INT      2.9     Block 1561 ($619)            Block 119 ($077)
                   Bytes 486 & 487              Bytes 480 & 481
                   From  02    80               From  00    C8

  FP       2.9     Block 1529 ($5F9)            Block 95 ($05F)
                   Bytes 82  & 83               Bytes 168 & 169
                   From  02    80               From  00    C8

  FP  PAL  2.9     Block 1529 ($5F9)            Block 95 ($05F)
                   Bytes 146 & 147              Bytes 162 & 163
                   From  02    80               From  01    00

  FP       3.0     Block 1667 ($683)            Block 126 ($07E)
                   Bytes 60  & 61               Byte  425
                   From  02    80               From  64

  FP       3.1     Block 1765 ($6E5)            Block 131 ($083)
                   Bytes 424 & 425              Byte  343
                   From  02    80               From  64

Block + Offset is commonly used with most disk editors, but some use the Absolute Porition instead. Remember to divide the height of the screen by 4 first, and that you can't use values higher than 127 due to Impulses use of signed character storage. 127 will give you screen height of 508. I don't think its easily possible to hack Imagine to use an unsigned character to get a higher screen size. Anyone?

One Final Note: Imagine PC users have a whole different program than Amiga users. This modification will not work on the PC version. I would guess that a similar modification for the PC version would be more complicated, given that VGA modes are more complicated than Amiga modes.

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