move_cursor.gd

func move_cursor(direction: Vector3):
    var gridmap := Globals.gridmap_node # Specific to my codebase, ignore
    var cursor_position := Globals.state.cursor_position # Specific to my codebase, ignore

    var next_position := cursor_position
    var bound_max_x := 10
    var bound_min_x := 0
    var bound_max_z := 10
    var bound_min_z := 0

    while true:
        next_position += direction
        print("next_position: ", [next_position])

        # Handle looping on the other side
        # I'm pretty sure there is a way to do this without having to branch here, but i wrote this at 2am so... :D
        # Edit: i made a version without branching that should be way faster, but might be harder to read maybe? (see other move_cursor_no_branching.gd)
        if next_position.x >= bound_max_x:
            next_position.x = fmod(cursor_position.x + 1, bound_max_x)
        if next_position.x < bound_min_x:
            next_position.x = fmod(cursor_position.x + bound_max_x - 1, bound_max_x)
        if next_position.z >= bound_max_z:
            next_position.z = fmod(cursor_position.z + 1, bound_max_z)
        if next_position.z < bound_min_z:
            next_position.z = fmod(cursor_position.z + bound_max_z - 1, bound_max_z)

        var cell := gridmap.get_cell_item(next_position.x, next_position.y, next_position.z)
        if cell > -1:
            # we found it
            break
            
        # TODO: We could maybe break after gridmap.get_used_cells().size() tries if we wanted to, just to avoid infinite loops, but i don't think this can happen

        # Uncomment this to debug, just to avoid infinite loops
        # yield(get_tree(), "idle_frame")

    Globals.state.cursor_position = next_position  # Specific to my codebase, ignore
    get_node("%Cursor").transform.origin = next_position  # Specific to my codebase, ignore

move_cursor_no_branching.gd

func move_cursor(direction: Vector3):
    var gridmap := Globals.gridmap_node # Specific to my codebase, ignore
    var cursor_position := Globals.state.cursor_position # Specific to my codebase, ignore

    var next_position := cursor_position
    var bound_max_x := 10
    var bound_max_z := 10

    while true:
        # This code is assuming our map doesn't have negative coordinates (starts at 0,0,0)
        # Basically we add direction.x and if we go out of bounds_max, we loop around using modulo (fmod here)
        next_position = Vector3(
            fmod(bound_max_x + fmod(next_position.x + direction.x, bound_max_x), bound_max_x),
            next_position.y,
            fmod(bound_max_z + fmod(next_position.z + direction.z, bound_max_z), bound_max_z)
        )
        print("next_position: ", [next_position])

        var cell := gridmap.get_cell_item(int(next_position.x), int(next_position.y), int(next_position.z))
        if cell > -1:
            # we found it
            break

        # Uncomment this to debug, in case we are never breaking out of the loop
        # yield(get_tree(), "idle_frame")

    Globals.state.cursor_position = next_position  # Specific to my codebase, ignore
    get_node("%Cursor").transform.origin = next_position  # Specific to my codebase, ignore