nc_extended_rotating/hud.lua

local ipairs
    = ipairs

local minetest, nodecore
    = minetest, nodecore

local rotate = include("rotate")

local LABEL_ROTATION_HINT = "rotation hint"

local TEX_ROTATE_CLOCKWISE         = "nc_extended_rotating_hud_rotate_clockwise.png"
local TEX_ROTATE_COUNTER_CLOCKWISE = "nc_extended_rotating_hud_rotate_counter_clockwise.png"

local function do_player_rotating_checks(player, data)
    local pt = data.raycast()
    local node = pt and pt.type == "node" and minetest.get_node(pt.under)

    if node and rotate.is_rotatable(node) then
        local is_sneaking = player:get_player_control().sneak
        local texture = is_sneaking and TEX_ROTATE_COUNTER_CLOCKWISE or TEX_ROTATE_CLOCKWISE

        nodecore.hud_set(player, {
            label = LABEL_ROTATION_HINT,
            hud_elem_type = "image",
            text = texture .. "^[opacity:" .. 192,
            position  = { x = 0.5, y = 0.5 },
            offset    = { x = 0, y = 0 },
            alignment = { x = 0, y = 0 },
            scale     = { x = 1, y = 1 },
            quick = true
        })
    else
        nodecore.hud_set(player, {
            label = LABEL_ROTATION_HINT,
            ttl   = 0
        })
    end
end

nodecore.register_playerstep({
    label = "crosshair",
    priority = -101,
    action = do_player_rotating_checks,
})