[Coco] Help with algorithm in assembly...

[Walter ZAMBOTTI]

I think your forgetting the CoCo 16 color per pixel mode doesn't map 
directly to RGB values directly.

The values map to a palette which in turn provides the RGB value.

Which means unless you create palette values that coincide with RGB 
values your technique wont work.

Another way to tackle this is to load your image into GIMP and then tell 
GIMP to convert the image to a 16 or 15(+transparency) color image.

Once GIMP has this new palette remember to choose it when processing 
subsequent images.

GIMP will determine the best 15/16 colors that will recreate your 
original image and provide you the list of colors in the new palette.  
You can then find the closest  colors in the CoCo palette.

So do all your conversions before hand rather than on the fly.

On 15/10/22 23:59, Lee via Coco wrote:
> I'm attempting this myself, but I want to throw it out here for those that
> like a challenge, and because I'll probably get better ideas from all of
> you than what I come up with myself. 😀 Here's the scenario:
>
> I have a 16x16 image loaded into an 8*16 (128) byte buffer (tileBuffer).
> Each 8 bytes represents a 16-pixel row. Each 2 bytes in that row represent
> a color plane of bits for 16 pixels. The first 2 bytes are the red bits,
> next are green bits, then blue, then the last 2 bytes are intensity.
>
> I need to "decode" this into another 8*16 (128) byte buffer. Each 8 bytes
> represents a 16 pixel row. Each nibble (4 bits) holds the
> red/green/blue/intensity bits for a single pixel. This buffer is at an
> offset (tileIndex*8*16, tileIndex is 1 byte) in a larger buffer that holds
> 64 tiles (tileData).
>
> 6309 instructions are available for use.
>
> -----
> Lee
>