How to Make a New map_snow.tga

[BradenLord]

Tired of seeing all the farms turn to winter when you build your map_snow.tga? Me too. I couldn't find anything online explaining how this file is actually handled by Rome Remastered so I did some research and figured out how to make a new map_snow.tga work.

Basically, the main reason why your map_snow.tga doesn't work is because Rome Remastered expects to read the file as an 8bit TGA instead of 24bit like all other TGA files in the map.

Notice the difference if file sizes in vanilla's base map folder:
https://imgur.com/a/rFdcJj8

The map_snow is about 10x smaller, even though they are almost the same number of pixels!

Ok, so let's make our own map_snow.

To start, take your map_climates.tga and make a copy. Open it in your favorite image editor and magic select all of your climates that you would expect to see snow textures on them. Next, fill the color of those with pure white (255, 255, 255). Then, invert your selection and color the rest of the map pure black (255, 255, 255). You can grayscale colors in between these, but it does not seem to make much difference in my testing. Finally, resize your image to the the following formula: X = Climates X - 3, Y = Climates Y - 1. (Not sure if this is required, but following the convention from vanilla). Linked here are before and after examples of a map I am working on:
Before: https://imgur.com/a/p9KjUWP
After: https://imgur.com/a/4q6ug2O

Now save your copy as snow_base.tga with your other campaign map files and choose 24bit if possible with no compression (if your program doesn't have this it should still work, you will just have extra files later).
Next, we need to separate out or new file into three 8 bit channels. I did this with ImageMagick (https://imagemagick.org/script/index.php).

In the directory I ran the following command:

Spoiler Alert, click show to read: 

magick snow_base.tga -separate map_snow_new.tga

This spit out three files, map_snow_new-0, *-1 and *-2. Simply delete the ones ending and -1 and -2 and rename map_snow_new-0.tga into map_snow.tga. Notice they all have the same data. This is because grayscale can be represented by just R, B or G only (think gray scaling between 0 and 255). All three of these files are exactly the same and readable by Rome Remastered.

https://imgur.com/a/jb2XhBD

That's all there is to it! You'll now see snow farm overlays in the proper location in your campaign (make sure you aren't overriding textures in data/terrain/aerial_map/special!). Note that changes to map_snow.tga don't require you to rebuild the map.rwm file. Also, if you decide to make changes to your map_snow.tga in the editor, make sure to go through this splitting process again when your are ready to test in Rome Remastered.

Proof: https://imgur.com/a/3JxcR8r

Let me know if you have any questions, and enjoy your properly snow covered farms!

https://imgur.com/a/uY7ATp4