mesecons/mesecons_pressureplates/init.lua

local S = minetest.get_translator(minetest.get_current_modname())

local pp_box_off = {
	type = "fixed",
	fixed = { -7/16, -8/16, -7/16, 7/16, -7/16, 7/16 },
}

local pp_box_on = {
	type = "fixed",
	fixed = { -7/16, -8/16, -7/16, 7/16, -7.5/16, 7/16 },
}

local function obj_touching_plate_pos(obj_ref, plate_pos)
	local obj_pos = obj_ref:get_pos()
	local props = obj_ref:get_properties()
	if not (props and obj_pos and not obj_ref:get_attach()) then
		return false
	end

	local collisionbox = props.collisionbox
	local physical = props.physical
	local is_player = obj_ref:is_player()
	local luaentity = obj_ref:get_luaentity()
	local is_item = luaentity and luaentity.name == "__builtin:item"
	if not (collisionbox and physical or is_player or is_item) then
		return false
	end

	local plate_x_min = plate_pos.x - 7 / 16
	local plate_x_max = plate_pos.x + 7 / 16
	local plate_z_min = plate_pos.z - 7 / 16
	local plate_z_max = plate_pos.z + 7 / 16
	local plate_y_min = plate_pos.y - 8 / 16
	local plate_y_max = plate_pos.y - 6.5 / 16

	local obj_x_min = obj_pos.x + collisionbox[1]
	local obj_x_max = obj_pos.x + collisionbox[4]
	local obj_z_min = obj_pos.z + collisionbox[3]
	local obj_z_max = obj_pos.z + collisionbox[6]
	local obj_y_min = obj_pos.y + collisionbox[2]
	local obj_y_max = obj_pos.y + collisionbox[5]

	if
		obj_y_min < plate_y_max and
		obj_y_max > plate_y_min and
		obj_x_min < plate_x_max and
		obj_x_max > plate_x_min and
		obj_z_min < plate_z_max and
		obj_z_max > plate_z_min
	then
		return true
	end
	return false
end

local function pp_on_timer(pos)
	local node = minetest.get_node(pos)
	local basename = minetest.registered_nodes[node.name].pressureplate_basename

	-- This is a workaround for a strange bug that occurs when the server is started
	-- For some reason the first time on_timer is called, the pos is wrong
	if not basename then return end

	local objs = minetest.get_objects_inside_radius(pos, 1)
	local obj_touching = false
	for k, obj in pairs(objs) do
		if obj_touching_plate_pos(obj, pos) then
			obj_touching = true
			break
		end
	end

	if not obj_touching and node.name == basename .. "_on" then
		minetest.set_node(pos, {name = basename .. "_off"})
		mesecon.receptor_off(pos, mesecon.rules.pplate)
	elseif obj_touching and node.name == basename .. "_off" then
		minetest.set_node(pos, {name = basename .. "_on"})
		mesecon.receptor_on(pos, mesecon.rules.pplate )
	end
	return true
end

-- Register a Pressure Plate
-- offstate:	name of the pressure plate when inactive
-- onstate:	name of the pressure plate when active
-- description:	description displayed in the player's inventory
-- tiles_off:	textures of the pressure plate when inactive
-- tiles_on:	textures of the pressure plate when active
-- image:	inventory and wield image of the pressure plate
-- recipe:	crafting recipe of the pressure plate
-- groups:	groups
-- sounds:	sound table

function mesecon.register_pressure_plate(basename, description, textures_off, textures_on, image_w, image_i, recipe, groups, sounds)
	if not groups then
		groups = {}
	end
	local groups_off = table.copy(groups)
	local groups_on = table.copy(groups)
	groups_on.not_in_creative_inventory = 1

	mesecon.register_node(basename, {
		drawtype = "nodebox",
		inventory_image = image_i,
		wield_image = image_w,
		paramtype = "light",
		is_ground_content = false,
		description = description,
		pressureplate_basename = basename,
		on_timer = pp_on_timer,
		on_construct = function(pos)
			minetest.get_node_timer(pos):start(mesecon.setting("pplate_interval", 0.1))
		end,
		sounds = sounds,
	},{
		mesecons = {receptor = { state = mesecon.state.off, rules = mesecon.rules.pplate }},
		node_box = pp_box_off,
		selection_box = pp_box_off,
		groups = groups_off,
		tiles = textures_off
	},{
		mesecons = {receptor = { state = mesecon.state.on, rules = mesecon.rules.pplate }},
		node_box = pp_box_on,
		selection_box = pp_box_on,
		groups = groups_on,
		tiles = textures_on
	})

	minetest.register_craft({
		output = basename .. "_off",
		recipe = recipe,
	})
end

mesecon.register_pressure_plate(
	"mesecons_pressureplates:pressure_plate_wood",
	S("Wooden Pressure Plate"),
	{"jeija_pressure_plate_wood_off.png","jeija_pressure_plate_wood_off.png","jeija_pressure_plate_wood_off_edges.png"},
	{"jeija_pressure_plate_wood_on.png","jeija_pressure_plate_wood_on.png","jeija_pressure_plate_wood_on_edges.png"},
	"jeija_pressure_plate_wood_wield.png",
	"jeija_pressure_plate_wood_inv.png",
	{{"group:wood", "group:wood"}},
	{ choppy = 3, oddly_breakable_by_hand = 3 },
	mesecon.node_sound.wood)

mesecon.register_pressure_plate(
	"mesecons_pressureplates:pressure_plate_stone",
	S("Stone Pressure Plate"),
	{"jeija_pressure_plate_stone_off.png","jeija_pressure_plate_stone_off.png","jeija_pressure_plate_stone_off_edges.png"},
	{"jeija_pressure_plate_stone_on.png","jeija_pressure_plate_stone_on.png","jeija_pressure_plate_stone_on_edges.png"},
	"jeija_pressure_plate_stone_wield.png",
	"jeija_pressure_plate_stone_inv.png",
	{{"mesecons_gamecompat:cobble", "mesecons_gamecompat:cobble"}},
	{ cracky = 3, oddly_breakable_by_hand = 3 },
	mesecon.node_sound.stone)