jOnas - Here is a copy of my scratch.txt file, where I would sometimes write code and data before copying it into bgb. It is all just a bunch of random code or data, but later in the work I started to note down where in the rom I was putting the bits of data etc.
https://filebin.net/944p14o5b6padq9jI'll also include it in the zip with the next bugfix patch when it is ready.
The map color data, as well as the title screen and win screen is in a format where you specify chucks of data.
each chunk has 2 bytes of address (where the data starts getting written), then 1 byte that has write type and number of bytes, and then the actual data.
For the type / number bytes if the x40 bit is set, then every byte is written the same. if the 0x40 bit isn't set, then you need to specify every byte.
ie, the // nice play below is starting at 9842, write 0xA bytes as 0x02. that will be used somewhere to set the color data for the nice play text on screen to palette 2, which is yellow/gold.
the green laurels line 9884 08 0303070707070303
means at 9884, write x08 bytes with 03 03 07 07 07 07 03 03 as the values.
Then the processing stops if the next byte after a chunk is a 00.
Last time I looked at the code that processes the chunks, it looks like there is also an option to write vertical lines of data on the map as well, but that isn't used as far as I could tell. I could have used it with the color data, so it is a pain I didn't see it before I did all the color maps.
If you have any other questions, feel free to ask.