How to Add Characters and Icons to the Font
Any icons specific to The Powder Toy are allocated from one of the private use areas of unicode: U+E000 through U+F8FF. If you wish to add a new icon you should allocate it from that range.
Compiling the font editor
The data for the font is specified in
resources/font.bz2 but editing that file by hand is a bad idea. The TPT source comes with a graphical editor for this file, which you can build by setting the
build_font option to
true, as explained in the meson guide. This will produce an executable called
font.exe. You will have to pass the path to
resources/font.bz2 to it as a command line argument, e.g.
font.exe ..\resources\font.bz2 or
Editing the font
font.bz2 using the font editor you will be presented with a GUI. The top part contains the character currently being edited. Below you can select the unicode codepoint you're currently looking at (in hexadecimal, or using the arrows), make the character wider or narrower, create or delete the character, toggle the grid and the rulers (take a look at several uppercase and lowercase characters, characters with lower hooks and accents, to see how these rulers are used).
Below you can configure the foreground and background colors for the editor (sometimes useful for multi-colored icons). "Render" reflects your changes in the font editor program itself, and "Save" saves your changes into
font.bz2. On the bottom left there is a text field into which you can enter codepoints in hexadecimal, and they will be rendered on the bottom right, this is to test what they look like among other text.
The font editor also supports some key bindings: Left and Right to switch between characters; Shift-Left, Right, Up, Down to shift the current character by 1 pixel in either direction; C to copy the current character and V to paste; Q to exit.
Once you're done with editing the font press "Save" and exit. This will update
font.bz2 so next time you compile TPT it will include your changes to the font.
Defines for the menu sections are located in
simulation/SimulationData.h. Take a look at
simulation/SimulationData.cpp. The first column is the unicode codepoint for the icon, the second column is the menu name. These are what you need to edit to create a new menu.