Handheld prospecting tool

The new tool will say whether a target block type is present in a
specified region, to allow for more targeted digging.  It is deliberately
quite weak, with several limitations: only stores enough charge for a
small number of shots; target can only be set by pointing at an example
node; range is limited; accuracy is less than 100%.  Some of these
limitations should probably be ameliorated, but not entirely eliminated,
in the future when we have a better idea of game balance.

The inventory image is only a placeholder.

technic/tools/init.lua

@@ -13,6 +13,7 @@ dofile(path.."/cans.lua")
 dofile(path.."/chainsaw.lua")
 dofile(path.."/tree_tap.lua")
 dofile(path.."/sonic_screwdriver.lua")
+dofile(path.."/prospector.lua")
 
 if minetest.get_modpath("screwdriver") then
 	-- compatibility alias

technic/tools/prospector.lua

@@ -0,0 +1,126 @@
+local S = technic.getter
+
+technic.register_power_tool("technic:prospector", 15000)
+
+local function get_metadata(toolstack)
+	local m = minetest.deserialize(toolstack:get_metadata())
+	if not m then m = {} end
+	if not m.charge then m.charge = 0 end
+	if not m.target then m.target = "" end
+	if not m.look_depth then m.look_depth = 7 end
+	if not m.look_radius then m.look_radius = 1 end
+	return m
+end
+
+minetest.register_tool("technic:prospector", {
+	description = S("Prospector"),
+	inventory_image = "technic_prospector.png",
+	wear_represents = "technic_RE_charge",
+	on_refill = technic.refill_RE_charge,
+	on_use = function(toolstack, user, pointed_thing)
+		if not user or not user:is_player() or user.is_fake_player then return end
+		if pointed_thing.type ~= "node" then return end
+		local toolmeta = get_metadata(toolstack)
+		local look_diameter = toolmeta.look_radius * 2 + 1
+		local charge_to_take = toolmeta.look_depth * (toolmeta.look_depth + 1) * look_diameter * look_diameter
+		if toolmeta.charge < charge_to_take then return end
+		if toolmeta.target == "" then
+			minetest.chat_send_player(user:get_player_name(), "Right-click to set target block type")
+			return
+		end
+		toolmeta.charge = toolmeta.charge - charge_to_take
+		toolstack:set_metadata(minetest.serialize(toolmeta))
+		technic.set_RE_wear(toolstack, toolmeta.charge, technic.power_tools[toolstack:get_name()])
+		local start_pos = pointed_thing.under
+		local forward = minetest.facedir_to_dir(minetest.dir_to_facedir(user:get_look_dir(), true))
+		local right = forward.x ~= 0 and { x=0, y=1, z=0 } or (forward.y ~= 0 and { x=0, y=0, z=1 } or { x=1, y=0, z=0 })
+		local up = forward.x ~= 0 and { x=0, y=0, z=1 } or (forward.y ~= 0 and { x=1, y=0, z=0 } or { x=0, y=1, z=0 })
+		local base_pos = vector.add(start_pos, vector.multiply(vector.add(right, up), - toolmeta.look_radius))
+		local found = false
+		for f = 0, toolmeta.look_depth-1 do
+			for r = 0, look_diameter-1 do
+				for u = 0, look_diameter-1 do
+					if minetest.get_node(vector.add(vector.add(vector.add(base_pos, vector.multiply(forward, f)), vector.multiply(right, r)), vector.multiply(up, u))).name == toolmeta.target then found = true end
+				end
+			end
+		end
+		if math.random() < 0.02 then found = not found end
+		minetest.chat_send_player(user:get_player_name(), minetest.registered_nodes[toolmeta.target].description.." is "..(found and "present" or "absent").." in "..look_diameter.."x"..look_diameter.."x"..toolmeta.look_depth.." region")
+		minetest.sound_play("technic_prospector_"..(found and "hit" or "miss"), { pos = vector.add(user:getpos(), { x = 0, y = 1, z = 0 }), gain = 1.0, max_hear_distance = 10 })
+		return toolstack
+	end,
+	on_place = function(toolstack, user, pointed_thing)
+		if not user or not user:is_player() or user.is_fake_player then return end
+		local toolmeta = get_metadata(toolstack)
+		local pointed
+		if pointed_thing.type == "node" then
+			local pname = minetest.get_node(pointed_thing.under).name
+			local pdef = minetest.registered_nodes[pname]
+			if pdef and (pdef.groups.not_in_creative_inventory or 0) == 0 and pname ~= toolmeta.target then
+				pointed = pname
+			end
+		end
+		local look_diameter = toolmeta.look_radius * 2 + 1
+		minetest.show_formspec(user:get_player_name(), "technic:prospector_control",
+			"size[7,8.5]"..
+			"item_image[0,0;1,1;"..toolstack:get_name().."]"..
+			"label[1,0;"..minetest.formspec_escape(toolstack:get_definition().description).."]"..
+			(toolmeta.target ~= "" and
+				"label[0,1.5;Current target:]"..
+				"label[0,2;"..minetest.formspec_escape(minetest.registered_nodes[toolmeta.target].description).."]"..
+				"item_image[0,2.5;1,1;"..toolmeta.target.."]" or
+				"label[0,1.5;No target set]")..
+			(pointed and
+				"label[3.5,1.5;May set new target:]"..
+				"label[3.5,2;"..minetest.formspec_escape(minetest.registered_nodes[pointed].description).."]"..
+				"item_image[3.5,2.5;1,1;"..pointed.."]"..
+				"button_exit[3.5,3.65;2,0.5;target_"..pointed..";Set target]" or
+				"label[3.5,1.5;No new target available]")..
+			"label[0,4.5;Region cross section:]"..
+			"label[0,5;"..look_diameter.."x"..look_diameter.."]"..
+			"label[3.5,4.5;Set region cross section:]"..
+			"button_exit[3.5,5.15;1,0.5;look_radius_0;1x1]"..
+			"button_exit[4.5,5.15;1,0.5;look_radius_1;3x3]"..
+			"button_exit[5.5,5.15;1,0.5;look_radius_3;7x7]"..
+			"label[0,6;Region depth:]"..
+			"label[0,6.5;"..toolmeta.look_depth.."]"..
+			"label[3.5,6;Set region depth:]"..
+			"button_exit[3.5,6.65;1,0.5;look_depth_7;7]"..
+			"button_exit[4.5,6.65;1,0.5;look_depth_14;14]"..
+			"button_exit[5.5,6.65;1,0.5;look_depth_21;21]"..
+			"label[0,7.5;Accuracy:]"..
+			"label[0,8;98%]")
+		return
+	end, 
+})
+
+minetest.register_on_player_receive_fields(function(user, formname, fields)
+        if formname ~= "technic:prospector_control" then return false end
+	if not user or not user:is_player() or user.is_fake_player then return end
+	local toolstack = user:get_wielded_item()
+	if toolstack:get_name() ~= "technic:prospector" then return true end
+	local toolmeta = get_metadata(toolstack)
+	for field, value in pairs(fields) do
+		if field:sub(1, 7) == "target_" then
+			toolmeta.target = field:sub(8)
+		end
+		if field:sub(1, 12) == "look_radius_" then
+			toolmeta.look_radius = field:sub(13)
+		end
+		if field:sub(1, 11) == "look_depth_" then
+			toolmeta.look_depth = field:sub(12)
+		end
+	end
+	toolstack:set_metadata(minetest.serialize(toolmeta))
+	user:set_wielded_item(toolstack)
+	return true
+end)
+ 
+minetest.register_craft({
+	output = "technic:prospector",
+	recipe = {
+		{"moreores:pick_silver", "moreores:mithril_block", "pipeworks:teleport_tube_1"},
+		{"technic:brass_ingot", "technic:control_logic_unit", "technic:brass_ingot"},
+		{"", "technic:brass_ingot", ""},
+	}
+})