« on: January 17, 2019, 11:57:27 am »
The current tile is the one that the system is rendering. So lets say the image index of SamusCustomJumpUpper.png is 1 and SamusCustomJumpLower.png is 2, Samus tiles face right in the ROM and 546(B) and 562(D) are the front tiles and 519(A) and 520(C) are the rear jumping tiles in the following arrangement:
So when rendering tile 546, the emulator finds the line with condition "CheckForTileA". The condition tells the emulator to check if a sprite 519 is located 8 pixels to the left of tile 546 (the current tile). If the sprite 519 is found then it will use SamusCustomJumpUpper.png
Unfortunately you cannot extend the replacement for sprite tiles, you can only do that for background tiles because the background tiles cover the whole screen but sprite tiles don't.
I use a tool to generate the conditions so they are pretty easy to work with.