[Coco] [Color Computer] Hex codes to change Coco 2 colors to any of Coco 3's

[Robert Gault]

I don't think there is any generic method for doing what you want as it 
will depend on whether the game uses artifact colors or standard PMODE colors.

The screen mode for PMODE graphics is controlled by $FF22 and the I/O 
paired bytes from $FFC0-$FFC5. If you find a section of code sending 
information to these bytes, you can try a technique I developed for 
modifying the MarkData games for the Coco3. Info is on the MarkData site 
and part of it follows:

* RESET INITIALIZATION

* USE TO REPLACE SAM PMODE SETUP WITH
* GIME "ARTIFACT" MODE SETUP

  LDA #$4C  COCO3 MODE
  STA $FF90  TELL GIME
  LDD #$8009  GRAPHICS MODE @ 128X192X4
  STA $FF98  TELL GIME
  STB $FF99  TELL GIME
  CLRA
  STA $FF9A  BLACK BORDER
  STA $FF9C  REMOVE ANY VERTICAL SCROLL
  LDD #$F080  POINT TO GRAPHICS SCREEN AT $78400; USE LOCATION/8
  STD $FF9D  TELL GIME
  LDD #9     BLACK & BLUE
  STD $FFB0  PALETTE 0&1
  LDD #$243F RED & WHITE
  STD $FFB2  PALETTE 2&3

* OLD CODE TO REMOVE

* LDA #$FF
* STA $FF22   SCREEN COMMAND
* STA $FFC0   PMODE COMMAND
* STA $FFC3
* STA $FFC5
* LDD #GSCRN
* LSRA
* LDX #$FFC6
* LDB #7
*C@ LSRA
* BCS A@
* STB ,X++
* BRA B@
*A@ STB 1,X
* LEAX 2,X
*B@ DECB
* BNE C@


dungeonsofdaggorath wrote:
> Hi all,
> 
> When I used to own a Coco 3, I learned a technique to modify the hex 
> codes within the binary file of a game to change:
> 
> 1. The 4 color graphics screen type (white or green border)
> 2. The actual color displayed
> 
> This was useful for modifying coco 2 games to any of the more 
> appealing colors of the coco 3.
> 
> I remember searching for a 2 byte hex string for the screen type, but 
> have no recollection of what it was.
> 
> Also, using the method mentioned above, is there a way to change the 
> screen mode from the 2 colors to the 4 colors?
> 
> If any body could shed some light on this, I'd be most grateful.
> 
> 
> 
> 
> 
> 
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