make a start on upgrade able mining drills

notes: they don't work. for some reason they should but they dont.

added recipes to craft them, and a replacement to get the energy crystal
back, along with the battery-less drill

mining_drill.lua

@@ -1,4 +1,18 @@
-mining_drill_max_charge=60000
+-- Max charge for the three different drills.
+
+-- Low power drill variable
+
+mining_drill_r_max_charge=60000
+
+-- Medium power drill variable
+
+mining_drill_g_max_charge=120000
+
+-- High power drill variable.
+
+mining_drill_b_max_charge=240000
+
+-- Lov voltage mining drill
 
 minetest.register_tool("technic:mining_drill", {
 	description = "Mining Drill",
@@ -13,7 +27,7 @@ minetest.register_tool("technic:mining_drill", {
 		 drill_dig_it(minetest.get_pointed_thing_position(pointed_thing, above),user)
 		 charge =charge-200;	
 		item["metadata"]=tostring(charge)
-		set_RE_wear(item,charge,mining_drill_max_charge)
+		set_RE_wear(item,charge,mining_drill_r_max_charge)
 		itemstack:replace(item)
 		end
 		return itemstack
@@ -21,19 +35,129 @@ minetest.register_tool("technic:mining_drill", {
 	end,
 })
 
+-- Medium Voltage mining drill
+
+minetest.register_tool("technic:mining_drill_g", {
+	description = "Mining Drill",
+	inventory_image = "technic_mining_drill.png",
+	stack_max = 1,
+	on_use = function(itemstack, user, pointed_thing)
+		if pointed_thing.type=="node" then 
+		item=itemstack:to_table()
+		if item["metadata"]=="" or item["metadata"]=="0" then return end --tool not charged 
+		charge=tonumber(item["metadata"]) 
+		if charge-200>0 then
+		 drill_dig_it(minetest.get_pointed_thing_position(pointed_thing, above),user)
+		 charge =charge-200;	
+		item["metadata"]=tostring(charge)
+		set_RE_wear(item,charge,mining_drill_g_max_charge)
+		itemstack:replace(item)
+		end
+		return itemstack
+		end
+	end,
+})
+
+-- High voltage mining drill
+
+minetest.register_tool("technic:mining_drill_b", {
+	description = "Mining Drill",
+	inventory_image = "technic_mining_drill.png",
+	stack_max = 1,
+	on_use = function(itemstack, user, pointed_thing)
+		if pointed_thing.type=="node" then 
+		item=itemstack:to_table()
+		if item["metadata"]=="" or item["metadata"]=="0" then return end --tool not charged 
+		charge=tonumber(item["metadata"]) 
+		if charge-200>0 then
+		 drill_dig_it(minetest.get_pointed_thing_position(pointed_thing, above),user)
+		 charge =charge-200;	
+		item["metadata"]=tostring(charge)
+		set_RE_wear(item,charge,mining_drill_b_max_charge)
+		itemstack:replace(item)
+		end
+		return itemstack
+		end
+	end,
+})
+
+-- Create a craftitem drill
+
+minetest.register_craftitem( "technic:mining_drill_empty", {
+	description = "Mining Drill",
+	inventory_image = "technic_mining_drill.png",
+	on_place_on_ground = minetest.craftitem_place_item,
+})
+
+-- Low Power mining drill
+
 minetest.register_craft({
 	output = 'technic:mining_drill',
+	recipe = {
+		{'', 'technic:mining_drill_empty', ''},
+		{'', 'technic:red_energy_crystal', ''},
+	}
+})
+
+-- Medium power mining drill
+
+minetest.register_craft({
+	output = 'technic:mining_drill_g',
+	recipe = {
+		{'', 'technic:mining_drill_empty', ''},
+		{'', 'technic:green_energy_crystal', ''},
+	}
+})
+
+-- High power mining drill
+
+minetest.register_craft({
+	output = 'technic:mining_drill_b',
+	recipe = {
+		{'', 'technic:mining_drill_empty', ''},
+		{'', 'technic:blue_energy_crystal', ''},
+	}
+})
+
+-- Register a craft for the useless mining drill.
+
+minetest.register_craft({
+	output = 'technic:mining_drill_empty',
 	recipe = {
 		{'technic:stainless_steel_ingot', 'technic:diamond_drill_head', 'technic:stainless_steel_ingot'},
-		{'technic:stainless_steel_ingot', 'technic:red_energy_crystal', 'technic:stainless_steel_ingot'},
+		{'technic:stainless_steel_ingot', '', 'technic:stainless_steel_ingot'},
 		{'', 'moreores:copper_ingot', ''},
 	}
 })
 
+-- These return the energy crystal and the empty mining drill
+
+minetest.register_craft({
+	output = 'technic:red_energy_crystal',
+	recipe = {
+		{'', 'technic:mining_drill', ''},
+	},
+	replacements = { { 'technic:mining_drill', 'technic:mining_drill_empty' }, },
+})
+
+minetest.register_craft({
+	output = 'technic:green_energy_crystal',
+	recipe = {
+		{'', 'technic:mining_drill_g', ''},
+	},
+	replacements = { { 'technic:mining_drill_g', 'technic:mining_drill_empty' }, },
+})
+
+minetest.register_craft({
+	output = 'technic:blue_energy_crystal',
+	recipe = {
+		{'', 'technic:mining_drill_b', ''},
+	},
+	replacements = { { 'technic:mining_drill_b', 'technic:mining_drill_empty' }, },
+})
 
 
-
-
+-- Function for digging blocks that is not either lava or water.
 
 function drill_dig_it (pos, player)		
 	local node=minetest.env:get_node(pos)