This tutorial explains how to take tiles from one 2-palette tileset and add them to another 2-palette tileset without quality loss. I'd recommend giving it a brief readthrough before going along with it, just so you'll know what's up. I only started taking screenshots of the process by step 4, so bare with me. Click 'em if they're to small.


1. Determine which tileset you will be adding tiles too, and which tileset you will be taking tiles from. For this tutorial, I'll be adding tiles from the bonus room tileset to the grasslands tileset as an example. I would suggest adding to the tileset that would be more inconvenient to remap, as any tiles you add will need that done to them.


2. Figure out the names of the tilesets you will be adding to/taking from. I thought there was a list of what tilesets corresponded to which NCGs/NCLs, but I couldn't find it. Luckily, its easy to figure it out yourself-- simply open the tileset in the editor, go to the graphics tab, and write down the file name listed under "Bitmaps" somewhere. Do this for both tilesets, and take note of which is which as well.


3. Find their palettes in the file explorer. They should be named in basically the same way their bitmaps are, but with "ncl" instead of "ncg" in their names. You can find them in the BG_ncl folder. Once you've found them, decompress both of them.


4. Open the palette of the tileset you are taking tiles from with the hex editor. Copy everything in the large middle column and exit.

Now, open the palette of the tileset you are adding tiles to in the hex editor, go to the end of the large middle column, and paste everything you copied earlier.

Then, save, exit, and lz77 compress the palettes. To check if this all is going well so far, try opening the palette of the tileset you are adding tiles to normally and see if it has 4 palettes now. If it does, go on to step 5. If not, either backtrack, ask for clarification, or I guess just ask me to do it if you really can't figure it out.


5. Now, if you're doing this in a throwaway rom, you can just replace any palette file with this one. If you're not using a throwaway rom, you can either replace the palette of the tileset you're taking tiles from (as I'm assuming you're going to import some other tileset over it anyway) or extract some other palette file, replace it with this one, then put it back when you're done with the tutorial. I'd recommend the former. Now, open the graphics of the two tilesets you're gonna merge in the file explorer (they'll be in the BG_ncg folder). Open the one you're adding tiles to first and the one you're taking tiles from second, then add the 2nd palette from this ncl to the bitmaps.

Afterwards, click the "Export all bitmaps with all palettes button", name the png as whatever, and close the tileset you're taking tiles from by right clicking its file name in the "Bitmaps" list. Keep the tileset you're adding tiles to open in the graphics editor.


6. Open the newly exported png in a graphics editor of your choice. I'll be using GIMP, but any program that supports transparency, copying and pasting, and cropping will do. You may also want a reference image of the original tileset graphics, an 8x8 grid, and a way to easily distinguish the left and right halves of the image, but these are ultimately optional. The 256x112 pixel area on the right is the area you'll be taking tiles from, and the area on the left is the one you'll be adding tiles to. You may need to leave behind some tiles, trim duplicates, etc. etc., to make everything fit into the area on the left side.

Once you've gotten everything you want moved, crop the area on the left to 256x112 pixels and save.



7. Now, remember how you left the graphics of the tileset you're adding tiles to open? I should hope so. Open that up and click the "Import this bitmap with existing palette" button and select the modified png you just saved. Make sure you click the button that says "Import this bitmap with existing palette" and NOT the one that says "Import this bitmap and recreate palette".

Once you've done that, save it and close the graphics editor.


8. All you have to do now is open the tileset you added tiles to in the tileset editor and do stuff like remapping and defining the tile behaviors and such of the tiles you added. All the tiles you added should be using palettes 3 and 4.

After you've done all that, just save and you're done!


If you have any questions or just suggestions on how I could phrase all this better, I would encourage leaving them, as I wrote all this pretty late.