minetest-mod-mesecons/mesecons_pistons/init.lua

-- Get mesecon rules of pistons
piston_rules =
{{x=0,  y=0,  z=1}, --everything apart from z- (pusher side)
 {x=1,  y=0,  z=0},
 {x=-1, y=0,  z=0},
 {x=1,  y=1,  z=0},
 {x=1,  y=-1, z=0},
 {x=-1, y=1,  z=0},
 {x=-1, y=-1, z=0},
 {x=0,  y=1,  z=1},
 {x=0,  y=-1, z=1}}

local piston_get_rules = function (node)
	local rules = piston_rules
	for i = 1, node.param2 do
		rules = mesecon:rotate_rules_left(rules)
	end
	return rules
end

piston_facedir_direction = function (node)
	local rules = {{x = 0, y = 0, z = -1}}
	for i = 1, node.param2 do
		rules = mesecon:rotate_rules_left(rules)
	end
	return rules[1]
end

piston_get_direction = function (dir, node)
	if type(dir) == "function" then
		return dir(node)
	else
		return dir
	end
end

local piston_remove_pusher = function (pos, node)
	pistonspec = minetest.registered_nodes[node.name].mesecons_piston

	dir = piston_get_direction(pistonspec.dir, node)
	local pusherpos = mesecon:addPosRule(pos, dir)
	local pushername = minetest.env:get_node(pusherpos).name

	if pushername == pistonspec.pusher then --make sure there actually is a pusher (for compatibility reasons mainly)
		minetest.env:remove_node(pusherpos)
		nodeupdate(pusherpos)
	end
end

local piston_on = function (pos, node)
	local pistonspec = minetest.registered_nodes[node.name].mesecons_piston

	dir = piston_get_direction(pistonspec.dir, node)
	local np = mesecon:addPosRule(pos, dir)
	success, stack = mesecon:mvps_push(np, dir, PISTON_MAXIMUM_PUSH)
	if success then
		minetest.env:add_node(pos, {param2 = node.param2, name = pistonspec.onname})
		minetest.env:add_node(np, {param2 = node.param2, name = pistonspec.pusher})
		mesecon:mvps_process_stack(stack)
	end
end

local piston_off = function (pos, node)
	local pistonspec = minetest.registered_nodes[node.name].mesecons_piston
	minetest.env:add_node(pos, {param2 = node.param2, name = pistonspec.offname})
	piston_remove_pusher (pos, node)

	if pistonspec.sticky then
		dir = piston_get_direction(pistonspec.dir, node)
		pullpos = mesecon:addPosRule(pos, dir)
		stack = mesecon:mvps_pull_single(pullpos, dir)
		mesecon:mvps_process_stack(stack)
	end
end

local piston_orientate = function (pos, placer)
	-- not placed by player
	if not placer then return end

	-- placer pitch in degrees
	local pitch = placer:get_look_pitch() * (180 / math.pi)

	local node = minetest.env:get_node(pos)
	local pistonspec = minetest.registered_nodes[node.name].mesecons_piston
	if pitch > 55 then --looking upwards
		minetest.env:add_node(pos, {name=pistonspec.piston_down})
	elseif pitch < -55 then --looking downwards
		minetest.env:add_node(pos, {name=pistonspec.piston_up})
	end
end


-- Horizontal pistons

local pt = 3/16 -- pusher thickness

local piston_pusher_box = {
	type = "fixed",
	fixed = {
		{-2/16, -2/16, -.5 + pt, 2/16, 2/16,  .5 + pt},
		{-.5  , -.5  , -.5     , .5  , .5  , -.5 + pt},
	}
}

local piston_on_box = {
	type = "fixed",
	fixed = {
		{-.5, -.5, -.5 + pt, .5, .5, .5}
	}
}


-- Normal (non-sticky) ones:

local pistonspec_normal = {
	offname = "mesecons_pistons:piston_normal_off",
	onname = "mesecons_pistons:piston_normal_on",
	dir = piston_facedir_direction,
	pusher = "mesecons_pistons:piston_pusher_normal",
	piston_down = "mesecons_pistons:piston_down_normal_off",
	piston_up   = "mesecons_pistons:piston_up_normal_off",
}

-- offstate
minetest.register_node("mesecons_pistons:piston_normal_off", {
	description = "Piston",
	tiles = {
		"mesecons_piston_top.png", 
		"mesecons_piston_bottom.png", 
		"mesecons_piston_left.png", 
		"mesecons_piston_right.png", 
		"mesecons_piston_back.png", 
		"mesecons_piston_pusher_front.png"
		},
	groups = {cracky = 3},
	paramtype2 = "facedir",
	after_place_node = piston_orientate,
	mesecons_piston = pistonspec_normal,
	mesecons = {effector={
		action_on = piston_on,
		rules = piston_get_rules
	}}
})

-- onstate
minetest.register_node("mesecons_pistons:piston_normal_on", {
	drawtype = "nodebox",
	tiles = {
		"mesecons_piston_top.png", 
		"mesecons_piston_bottom.png", 
		"mesecons_piston_left.png", 
		"mesecons_piston_right.png", 
		"mesecons_piston_back.png", 
		"mesecons_piston_on_front.png"
		},
	inventory_image = "mesecons_piston_top.png",
	wield_image = "mesecons_piston_top.png",
	groups = {cracky = 3, not_in_creative_inventory = 1},
	paramtype = "light",
	paramtype2 = "facedir",
	drop = "mesecons_pistons:piston_normal_off",
	after_dig_node = piston_remove_pusher,
	node_box = piston_on_box,
	selection_box = piston_on_box,
	mesecons_piston = pistonspec_normal,
	mesecons = {effector={
		action_off = piston_off,
		rules = piston_get_rules
	}}
})

-- pusher
minetest.register_node("mesecons_pistons:piston_pusher_normal", {
	drawtype = "nodebox",
	tiles = {
		"mesecons_piston_pusher_top.png",
		"mesecons_piston_pusher_bottom.png",
		"mesecons_piston_pusher_left.png",
		"mesecons_piston_pusher_right.png",
		"mesecons_piston_pusher_back.png",
		"mesecons_piston_pusher_front.png"
		},
	paramtype = "light",
	paramtype2 = "facedir",
	diggable = false,
	corresponding_piston = "mesecons_pistons:piston_normal_on",
	selection_box = piston_pusher_box,
	node_box = piston_pusher_box,
})

-- Sticky ones

local pistonspec_sticky = {
	offname = "mesecons_pistons:piston_sticky_off",
	onname = "mesecons_pistons:piston_sticky_on",
	dir = piston_facedir_direction,
	pusher = "mesecons_pistons:piston_pusher_sticky",
	sticky = true,
	piston_down = "mesecons_pistons:piston_down_sticky_off",
	piston_up   = "mesecons_pistons:piston_up_sticky_off",
}

-- offstate
minetest.register_node("mesecons_pistons:piston_sticky_off", {
	description = "Sticky Piston",
	tiles = {
		"mesecons_piston_top.png", 
		"mesecons_piston_bottom.png", 
		"mesecons_piston_left.png", 
		"mesecons_piston_right.png", 
		"mesecons_piston_back.png", 
		"mesecons_piston_pusher_front_sticky.png"
		},
	groups = {cracky = 3},
	paramtype2 = "facedir",
	after_place_node = piston_orientate,
	mesecons_piston = pistonspec_sticky,
	mesecons = {effector={
		action_on = piston_on,
		rules = piston_get_rules
	}}
})

-- onstate
minetest.register_node("mesecons_pistons:piston_sticky_on", {
	drawtype = "nodebox",
	tiles = {
		"mesecons_piston_top.png", 
		"mesecons_piston_bottom.png", 
		"mesecons_piston_left.png", 
		"mesecons_piston_right.png", 
		"mesecons_piston_back.png", 
		"mesecons_piston_on_front.png"
		},
	inventory_image = "mesecons_piston_top.png",
	wield_image = "mesecons_piston_top.png",
	groups = {cracky = 3, not_in_creative_inventory = 1},
	paramtype = "light",
	paramtype2 = "facedir",
	drop = "mesecons_pistons:piston_normal_off",
	after_dig_node = piston_remove_pusher,
	node_box = piston_on_box,
	selection_box = piston_on_box,
	mesecons_piston = pistonspec_sticky,
	mesecons = {effector={
		action_off = piston_off,
		rules = piston_get_rules
	}}
})

-- pusher
minetest.register_node("mesecons_pistons:piston_pusher_sticky", {
	drawtype = "nodebox",
	tiles = {
		"mesecons_piston_pusher_top.png",
		"mesecons_piston_pusher_bottom.png",
		"mesecons_piston_pusher_left.png",
		"mesecons_piston_pusher_right.png",
		"mesecons_piston_pusher_back.png",
		"mesecons_piston_pusher_front_sticky.png"
		},
	paramtype = "light",
	paramtype2 = "facedir",
	diggable = false,
	corresponding_piston = "mesecons_pistons:piston_sticky_on",
	selection_box = piston_pusher_box,
	node_box = piston_pusher_box,
})

--
--
-- UP
--
--

local piston_up_pusher_box = {
	type = "fixed",
	fixed = {
		{-2/16, -.5 - pt, -2/16, 2/16, .5, 2/16},
		{-.5  ,  .5 - pt, -.5  , .5  , .5,   .5},
	}
}

local piston_up_on_box = {
	type = "fixed",
	fixed = {
		{-.5, -.5, -.5 , .5, .5-pt, .5}
	}
}

-- Normal

local pistonspec_normal_up = {
	offname = "mesecons_pistons:piston_up_normal_off",
	onname = "mesecons_pistons:piston_up_normal_on",
	dir = {x = 0, y = 1, z = 0},
	pusher = "mesecons_pistons:piston_up_pusher_normal"
}

-- offstate
minetest.register_node("mesecons_pistons:piston_up_normal_off", {
	tiles = {
		"mesecons_piston_pusher_front.png",
		"mesecons_piston_back.png", 
		"mesecons_piston_left.png^[transformR270", 
		"mesecons_piston_right.png^[transformR90", 
		"mesecons_piston_bottom.png", 
		"mesecons_piston_top.png^[transformR180", 
		},
	inventory_image = "mesecons_piston_top.png",
	wield_image = "mesecons_piston_top.png",
	groups = {cracky = 3, not_in_creative_inventory = 1},
	paramtype2 = "facedir",
	drop = "mesecons_pistons:piston_normal_off",
	mesecons_piston = pistonspec_normal_up,
	mesecons = {effector={
		action_on = piston_on,
	}}
})

-- onstate
minetest.register_node("mesecons_pistons:piston_up_normal_on", {
	drawtype = "nodebox",
	tiles = {
		"mesecons_piston_on_front.png",
		"mesecons_piston_back.png", 
		"mesecons_piston_left.png^[transformR270", 
		"mesecons_piston_right.png^[transformR90", 
		"mesecons_piston_bottom.png", 
		"mesecons_piston_top.png^[transformR180", 
		},
	inventory_image = "mesecons_piston_top.png",
	wield_image = "mesecons_piston_top.png",
	groups = {cracky = 3, not_in_creative_inventory = 1},
	paramtype = "light",
	paramtype2 = "facedir",
	drop = "mesecons_pistons:piston_normal_off",
	after_dig_node = piston_remove_pusher,
	node_box = piston_up_on_box,
	selection_box = piston_up_on_box,
	mesecons_piston = pistonspec_normal_up,
	mesecons = {effector={
		action_off = piston_off,
	}}
})

-- pusher
minetest.register_node("mesecons_pistons:piston_up_pusher_normal", {
	drawtype = "nodebox",
	tiles = {
		"mesecons_piston_pusher_front.png",
		"mesecons_piston_pusher_back.png",
		"mesecons_piston_pusher_left.png^[transformR270",
		"mesecons_piston_pusher_right.png^[transformR90",
		"mesecons_piston_pusher_bottom.png",
		"mesecons_piston_pusher_top.png^[transformR180",
		},
	paramtype = "light",
	paramtype2 = "facedir",
	diggable = false,
	corresponding_piston = "mesecons_pistons:piston_up_normal_on",
	selection_box = piston_up_pusher_box,
	node_box = piston_up_pusher_box,
})



-- Sticky


local pistonspec_sticky_up = {
	offname = "mesecons_pistons:piston_up_sticky_off",
	onname = "mesecons_pistons:piston_up_sticky_on",
	dir = {x = 0, y = 1, z = 0},
	pusher = "mesecons_pistons:piston_up_pusher_sticky",
	sticky = true
}

-- offstate
minetest.register_node("mesecons_pistons:piston_up_sticky_off", {
	tiles = {
		"mesecons_piston_pusher_front_sticky.png",
		"mesecons_piston_back.png", 
		"mesecons_piston_left.png^[transformR270", 
		"mesecons_piston_right.png^[transformR90", 
		"mesecons_piston_bottom.png", 
		"mesecons_piston_top.png^[transformR180", 
		"mesecons_piston_tb.png"
		},
	inventory_image = "mesecons_piston_top.png",
	wield_image = "mesecons_piston_top.png",
	groups = {cracky = 3, not_in_creative_inventory = 1},
	paramtype2 = "facedir",
	drop = "mesecons_pistons:piston_sticky_off",
	mesecons_piston = pistonspec_sticky_up,
	mesecons = {effector={
		action_on = piston_on,
	}}
})

-- onstate
minetest.register_node("mesecons_pistons:piston_up_sticky_on", {
	drawtype = "nodebox",
	tiles = {
		"mesecons_piston_on_front.png",
		"mesecons_piston_back.png", 
		"mesecons_piston_left.png^[transformR270", 
		"mesecons_piston_right.png^[transformR90", 
		"mesecons_piston_bottom.png", 
		"mesecons_piston_top.png^[transformR180", 
		},
	inventory_image = "mesecons_piston_top.png",
	wield_image = "mesecons_piston_top.png",
	groups = {cracky = 3, not_in_creative_inventory = 1},
	paramtype = "light",
	paramtype2 = "facedir",
	drop = "mesecons_pistons:piston_normal_off",
	after_dig_node = piston_remove_pusher,
	node_box = piston_up_on_box,
	selection_box = piston_up_on_box,
	mesecons_piston = pistonspec_sticky_up,
	mesecons = {effector={
		action_off = piston_off,
	}}
})

-- pusher
minetest.register_node("mesecons_pistons:piston_up_pusher_sticky", {
	drawtype = "nodebox",
	tiles = {
		"mesecons_piston_pusher_front_sticky.png",
		"mesecons_piston_pusher_back.png",
		"mesecons_piston_pusher_left.png^[transformR270",
		"mesecons_piston_pusher_right.png^[transformR90",
		"mesecons_piston_pusher_bottom.png",
		"mesecons_piston_pusher_top.png^[transformR180",
		},
	paramtype = "light",
	paramtype2 = "facedir",
	diggable = false,
	corresponding_piston = "mesecons_pistons:piston_up_sticky_on",
	selection_box = piston_up_pusher_box,
	node_box = piston_up_pusher_box,
})

--
--
-- DOWN
--
--

local piston_down_pusher_box = {
	type = "fixed",
	fixed = {
		{-2/16, -.5, -2/16, 2/16,  .5 + pt, 2/16},
		{-.5  , -.5, -.5  , .5  , -.5 + pt,   .5},
	}
}

local piston_down_on_box = {
	type = "fixed",
	fixed = {
		{-.5, -.5+pt, -.5 , .5, .5, .5}
	}
}



-- Normal

local pistonspec_normal_down = {
	offname = "mesecons_pistons:piston_down_normal_off",
	onname = "mesecons_pistons:piston_down_normal_on",
	dir = {x = 0, y = -1, z = 0},
	pusher = "mesecons_pistons:piston_down_pusher_normal",
}

-- offstate
minetest.register_node("mesecons_pistons:piston_down_normal_off", {
	tiles = {
		"mesecons_piston_back.png", 
		"mesecons_piston_pusher_front.png",
		"mesecons_piston_left.png^[transformR90", 
		"mesecons_piston_right.png^[transformR270", 
		"mesecons_piston_bottom.png^[transformR180", 
		"mesecons_piston_top.png", 
		},
	inventory_image = "mesecons_piston_top.png",
	wield_image = "mesecons_piston_top.png",
	groups = {cracky = 3, not_in_creative_inventory = 1},
	paramtype2 = "facedir",
	drop = "mesecons_pistons:piston_normal_off",
	mesecons_piston = pistonspec_normal_down,
	mesecons = {effector={
		action_on = piston_on,
	}}
})

-- onstate
minetest.register_node("mesecons_pistons:piston_down_normal_on", {
	drawtype = "nodebox",
	tiles = {
		"mesecons_piston_back.png", 
		"mesecons_piston_on_front.png",
		"mesecons_piston_left.png^[transformR90", 
		"mesecons_piston_right.png^[transformR270", 
		"mesecons_piston_bottom.png^[transformR180", 
		"mesecons_piston_top.png", 
		},
	inventory_image = "mesecons_piston_top.png",
	wield_image = "mesecons_piston_top.png",
	groups = {cracky = 3, not_in_creative_inventory = 1},
	paramtype = "light",
	paramtype2 = "facedir",
	drop = "mesecons_pistons:piston_normal_off",
	after_dig_node = piston_remove_pusher,
	node_box = piston_down_on_box,
	selection_box = piston_down_on_box,
	mesecons_piston = pistonspec_normal_down,
	mesecons = {effector={
		action_off = piston_off,
	}}
})

-- pusher
minetest.register_node("mesecons_pistons:piston_down_pusher_normal", {
	drawtype = "nodebox",
	tiles = {
		"mesecons_piston_pusher_back.png",
		"mesecons_piston_pusher_front.png",
		"mesecons_piston_pusher_left.png^[transformR90",
		"mesecons_piston_pusher_right.png^[transformR270",
		"mesecons_piston_pusher_bottom.png^[transformR180",
		"mesecons_piston_pusher_top.png",
		},
	paramtype = "light",
	paramtype2 = "facedir",
	diggable = false,
	corresponding_piston = "mesecons_pistons:piston_down_normal_on",
	selection_box = piston_down_pusher_box,
	node_box = piston_down_pusher_box,
})

-- Sticky

local pistonspec_sticky_down = {
	onname = "mesecons_pistons:piston_down_sticky_on",
	offname = "mesecons_pistons:piston_down_sticky_off",
	dir = {x = 0, y = -1, z = 0},
	pusher = "mesecons_pistons:piston_down_pusher_sticky",
	sticky = true
}

-- offstate
minetest.register_node("mesecons_pistons:piston_down_sticky_off", {
	tiles = {
		"mesecons_piston_back.png", 
		"mesecons_piston_pusher_front_sticky.png",
		"mesecons_piston_left.png^[transformR90", 
		"mesecons_piston_right.png^[transformR270", 
		"mesecons_piston_bottom.png^[transformR180", 
		"mesecons_piston_top.png", 
		},
	inventory_image = "mesecons_piston_top.png",
	wield_image = "mesecons_piston_top.png",
	groups = {cracky = 3, not_in_creative_inventory = 1},
	paramtype2 = "facedir",
	drop = "mesecons_pistons:piston_sticky_off",
	mesecons_piston = pistonspec_sticky_down,
	mesecons = {effector={
		action_on = piston_on,
	}}
})

-- onstate
minetest.register_node("mesecons_pistons:piston_down_sticky_on", {
	drawtype = "nodebox",
	tiles = {
		"mesecons_piston_back.png", 
		"mesecons_piston_on_front.png",
		"mesecons_piston_left.png^[transformR90", 
		"mesecons_piston_right.png^[transformR270", 
		"mesecons_piston_bottom.png^[transformR180", 
		"mesecons_piston_top.png", 
		},
	inventory_image = "mesecons_piston_top.png",
	wield_image = "mesecons_piston_top.png",
	groups = {cracky = 3, not_in_creative_inventory = 1},
	paramtype = "light",
	paramtype2 = "facedir",
	drop = "mesecons_pistons:piston_sticky_off",
	after_dig_node = piston_remove_pusher,
	node_box = piston_down_on_box,
	selection_box = piston_down_on_box,
	mesecons_piston = pistonspec_sticky_down,
	mesecons = {effector={
		action_off = piston_off,
	}}
})

-- pusher
minetest.register_node("mesecons_pistons:piston_down_pusher_sticky", {
	drawtype = "nodebox",
	tiles = {
		"mesecons_piston_pusher_back.png",
		"mesecons_piston_pusher_front_sticky.png",
		"mesecons_piston_pusher_left.png^[transformR90",
		"mesecons_piston_pusher_right.png^[transformR270",
		"mesecons_piston_pusher_bottom.png^[transformR180",
		"mesecons_piston_pusher_top.png",
		},
	paramtype = "light",
	paramtype2 = "facedir",
	diggable = false,
	corresponding_piston = "mesecons_pistons:piston_down_sticky_on",
	selection_box = piston_down_pusher_box,
	node_box = piston_down_pusher_box,
})


-- Register pushers as stoppers if they would be seperated from the piston
local piston_pusher_get_stopper = function (node, dir, stack, stackid)
	if (stack[stackid + 1]
	and stack[stackid + 1].node.name   == minetest.registered_nodes[node.name].corresponding_piston
	and stack[stackid + 1].node.param2 == node.param2)
	or (stack[stackid - 1]
	and stack[stackid - 1].node.name   == minetest.registered_nodes[node.name].corresponding_piston
	and stack[stackid - 1].node.param2 == node.param2) then
		return false
	end
	return true
end

local piston_pusher_up_down_get_stopper = function (node, dir, stack, stackid)
	if (stack[stackid + 1]
	and stack[stackid + 1].node.name   == minetest.registered_nodes[node.name].corresponding_piston)
	or (stack[stackid - 1]
	and stack[stackid - 1].node.name   == minetest.registered_nodes[node.name].corresponding_piston) then
		return false
	end
	return true
end

mesecon:register_mvps_stopper("mesecons_pistons:piston_pusher_normal", piston_pusher_get_stopper)
mesecon:register_mvps_stopper("mesecons_pistons:piston_pusher_sticky", piston_pusher_get_stopper)

mesecon:register_mvps_stopper("mesecons_pistons:piston_up_pusher_normal", piston_pusher_up_down_get_stopper)
mesecon:register_mvps_stopper("mesecons_pistons:piston_up_pusher_sticky", piston_pusher_up_down_get_stopper)

mesecon:register_mvps_stopper("mesecons_pistons:piston_down_pusher_normal", piston_pusher_up_down_get_stopper)
mesecon:register_mvps_stopper("mesecons_pistons:piston_down_pusher_sticky", piston_pusher_up_down_get_stopper)


-- Register pistons as stoppers if they would be seperated from the stopper
local piston_up_down_get_stopper = function (node, dir, stack, stackid)
	if (stack[stackid + 1]
	and stack[stackid + 1].node.name   == minetest.registered_nodes[node.name].mesecons_piston.pusher)
	or (stack[stackid - 1]
	and stack[stackid - 1].node.name   == minetest.registered_nodes[node.name].mesecons_piston.pusher) then
		return false
	end
	return true
end

local piston_get_stopper = function (node, dir, stack, stackid)
	pistonspec = minetest.registered_nodes[node.name].mesecons_piston
	dir = piston_get_direction(pistonspec.dir, node)
	local pusherpos  = mesecon:addPosRule(stack[stackid].pos, dir)
	local pushernode = minetest.env:get_node(pusherpos)

	if minetest.registered_nodes[node.name].mesecons_piston.pusher == pushernode.name then
		for _, s in ipairs(stack) do
			if  mesecon:cmpPos(s.pos, pusherpos) -- pusher is also to be pushed
			and s.node.param2 == node.param2 then
				return false
			end
		end
	end
	return true
end

mesecon:register_mvps_stopper("mesecons_pistons:piston_normal_on", piston_get_stopper)
mesecon:register_mvps_stopper("mesecons_pistons:piston_sticky_on", piston_get_stopper)

mesecon:register_mvps_stopper("mesecons_pistons:piston_up_normal_on", piston_up_down_get_stopper)
mesecon:register_mvps_stopper("mesecons_pistons:piston_up_sticky_on", piston_up_down_get_stopper)

mesecon:register_mvps_stopper("mesecons_pistons:piston_down_normal_on", piston_up_down_get_stopper)
mesecon:register_mvps_stopper("mesecons_pistons:piston_down_sticky_on", piston_up_down_get_stopper)

--craft recipes
minetest.register_craft({
	output = 'mesecons_pistons:piston_normal_off 2',
	recipe = {
		{"default:wood", "default:wood", "default:wood"},
		{"default:cobble", "default:steel_ingot", "default:cobble"},
		{"default:cobble", "group:mesecon_conductor_craftable", "default:cobble"},
	}
})

minetest.register_craft({
	output = "mesecons_pistons:piston_sticky_off",
	recipe = {
		{"mesecons_materials:glue"},
		{"mesecons_pistons:piston_normal_off"},
	}
})