A way for transparency to not overwrite tiles

[KadTableAttack]

I would like to ask if there is a way to make transparent pixels of your Terrain Set to not overwrite tiles already on the map.
Here is a quick example of what i mean
Screencast_20250809_134452.webm
At the first second of the video you can see I have 2 Terrain Sets I have set up. The gray area in the background is all transparent.
However when I try to draw one over the other the transparent areas also overwrite the information already on the map.
Is there a way to prevent this?
I found one way where I can use a different layer and it won't delete the grass but that again becomes an issue when I merge the layers again and transparency just deletes the grass on the bottom layer. It's a workaround but that means I'll have a LOT of layers i won't be able to merge until the map is done.

On an off-note: How come the tiles placed with the terrain brush are misaligned compared to regular brush?. The brush seems to be snapping to the corners/intersections of the grid instead of the centers of the tiles. Regular stamp brush works fine and places tiles inside the grid.

[bjorn]

I found one way where I can use a different layer and it won't delete the grass but that again becomes an issue when I merge the layers again and transparency just deletes the grass on the bottom layer.

This is because anything else would require rendering multiple tiles per cell, and tile layers only refer to one tile per cell. Possible solutions would be:

• Introducing a special "terrain layer" type, which stores terrain IDs such that the tiles can be derived from that while rendering.

• Generating combined tiles on-demand and adding them to the tileset such that they can be referenced by a single tile ID. This would not necessarily need image manipulation because the renderer could support "combined tiles" directly, rendering them as any combination of existing tiles.

The brush seems to be snapping to the corners/intersections of the grid instead of the centers of the tiles. Regular stamp brush works fine and places tiles inside the grid.

I guess here you're referring to the way it changes the corners of at least 4 adjacent tiles rather than one tile at a time. This is necessary because of the way the tile graphics work in a "Corner" terrain set. You can however offset your terrain layer(s) by half your tile size (in Layer Properties), to place those corners in the center of the tiles on other layers.