Help editing tiles in NES ROM's (I am currently using FCEUX)

I'm interested in editing the "tile" used at a certain location, I'll use Castlevania III as an example of what I am attempting to do/learn here.

Upon entering the swamp area there is a tree displayed right in front of you, HOWEVER there is an error in the tile layout.



As you can see the original displays the wrong tiles here; it's displaying TILE 90 and 91 - when it should be displaying 4A and 4B...
**I made the above EDITED image by using FCEUx then editing the 90 & 91 values in the PPU to be 4A & 4B - BUT When I switch to ROM view (so I can modify this to SAVE the ROM with these new TILE's) the data there doesn't seem to match/make sense with the actual TILE data value stored in the PPU (at this location)? (See below image)



As you can see here (below) the game does load the missing tiles to complete this tree later in the stage as seen here:


(Which is set to use palette 3F08...)



Here's what it looks like, as you'll note just changing the TILE from 90 to 4A leaves the palette block tied to it the same (Palette 3F0C) which is the blues from the background. I'd like to be able to set the palette to the "circled" palette block 3F08 (aka the tree colors)... again in ROM (not PPU) so I can save the ROM with the corrected tiles/palettes.

(Please note: I am able to edit the colors in ROM for each palette block - but if you change the "blues" block 3F0C (02 11 21)... to match the tree color palette 3F08 (08 29 17) - then all the other tiles set to use the blues palette will also be the tree color. So I need to just change which palette block this TILE located at 8,16 (TILE 90 aka 4A) uses....)

Here is the tree TILE next to the TILE in question... set to use palette 3F08.



Any help on where to edit this data in the "Debug/HEX Editor" then under "View ROM" section would be greatly appreciated!!

Statistics: Posted by AstarOfDavid — Sun Jun 30, 2024 9:09 am — Replies 3 — Views 122

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