Crafter/mods/player/player_interaction.lua

--hurt sound and disable fall damage group handling
minetest.register_on_player_hpchange(function(player, hp_change, reason)
	if reason.type == "fall" then
		if minetest.get_item_group(minetest.get_node(player:get_pos()).name, "disable_fall_damage") > 0 then
			return(0)
		end
	end
	if hp_change < 0 then
		minetest.sound_play("hurt", {object=player, gain = 1.0, max_hear_distance = 60,pitch = math.random(80,100)/100})
	end
	return(hp_change)
end, true)

--throw all items on death
minetest.register_on_dieplayer(function(player, reason)
	local pos = player:get_pos()
	local inv = player:get_inventory()
	
	for i = 1,inv:get_size("main") do
		local stack = inv:get_stack("main", i)
		local name = stack:get_name()
		local count = stack:get_count()
		if name ~= "" then
			local obj = minetest.add_item(pos, name.." "..count)
			if obj then
				obj:set_velocity(vector.new(math.random(-3,3),math.random(4,8),math.random(-3,3)))
			end
			inv:set_stack("main", i, ItemStack(""))
		else
			inv:set_stack("main", i, ItemStack(""))
		end
	end

	local stack = inv:get_stack("armor_head", 1)
	local name = stack:get_name()
	if name ~= "" then
		local obj = minetest.add_item(pos, name)
		if obj then
			obj:set_velocity(vector.new(math.random(-3,3),math.random(4,8),math.random(-3,3)))
		end
		inv:set_stack("armor_head", 1, ItemStack(""))
	end

	stack = inv:get_stack("armor_torso", 1)
	name = stack:get_name()
	if name ~= "" then
		local obj = minetest.add_item(pos, name)
		if obj then
			obj:set_velocity(vector.new(math.random(-3,3),math.random(4,8),math.random(-3,3)))
		end
		inv:set_stack("armor_torso", 1, ItemStack(""))
	end

	stack = inv:get_stack("armor_legs", 1)
	name = stack:get_name()
	if name ~= "" then
		local obj = minetest.add_item(pos, name)
		if obj then
			obj:set_velocity(vector.new(math.random(-3,3),math.random(4,8),math.random(-3,3)))
		end
		inv:set_stack("armor_legs", 1, ItemStack(""))
	end


	stack = inv:get_stack("armor_feet", 1)
	name = stack:get_name()
	if name ~= "" then
		local obj = minetest.add_item(pos, name)
		if obj then
			obj:set_velocity(vector.new(math.random(-3,3),math.random(4,8),math.random(-3,3)))
		end
		inv:set_stack("armor_feet", 1, ItemStack(""))
	end


	recalculate_armor(player)
end)


--this dumps the players crafting table on closing the inventory
dump_craft = function(player)
	local inv = player:get_inventory()
	local pos = player:get_pos()
	pos.y = pos.y + player:get_properties().eye_height
	for i = 1,inv:get_size("craft") do
		local item = inv:get_stack("craft", i)
		local obj = minetest.add_item(pos, item)
		if obj then
			local x=math.random(-2,2)*math.random()
			local y=math.random(2,5)
			local z=math.random(-2,2)*math.random()
			obj:set_velocity({x=x, y=y, z=z})
		end
		inv:set_stack("craft", i, nil)
	end
end


--play sound to keep up with player's placing vs inconsistent client placing sound 
minetest.register_on_placenode(function(pos, newnode, placer, oldnode, itemstack, pointed_thing)
	local node = minetest.registered_nodes[newnode.name]
	local sound = node.sounds
	local placing = ""
	if sound then
		placing = sound.placing
	end
	--only play the sound when is defined
	if type(placing) == "table" then
		minetest.sound_play(placing.name, {
			  pos = pos,
			  gain = placing.gain,
			  --pitch = math.random(60,100)/100
		})
	end
end)

--replace stack when empty (building)
minetest.register_on_placenode(function(pos, newnode, placer, oldnode, itemstack, pointed_thing)
	local old = itemstack:get_name()
	--pass through to check
	minetest.after(0,function(pos, newnode, placer, oldnode, itemstack, pointed_thing,old)
		if not placer then
			return
		end
		local new = placer:get_wielded_item():get_name()
		if old ~= new and new == "" then
			local inv = placer:get_inventory()
			--check if another stack
			if inv:contains_item("main", old) then
				--print("moving stack")
				--run through inventory
				for i = 1,inv:get_size("main") do
					--if found set wielded item and remove old stack
					if inv:get_stack("main", i):get_name() == old then
						local count = inv:get_stack("main", i):get_count()
						placer:set_wielded_item(old.." "..count)
						inv:set_stack("main",i,ItemStack(""))	
						minetest.sound_play("pickup", {
							  to_player = player,
							  gain = 0.7,
							  pitch = math.random(60,100)/100
						})
						return				
					end
				end
			end
		end
	end,pos, newnode, placer, oldnode, itemstack, pointed_thing,old)
end)

local do_critical_particles = function(pos)
	minetest.add_particlespawner({
		amount = 40,
		time = 0.001,
		minpos = pos,
		maxpos = pos,
		minvel = vector.new(-2,-2,-2),
		maxvel = vector.new(2,8,2),
		minacc = {x=0, y=4, z=0},
		maxacc = {x=0, y=12, z=0},
		minexptime = 1.1,
		maxexptime = 1.5,
		minsize = 1,
		maxsize = 2,
		collisiondetection = false,
		vertical = false,
		texture = "critical.png",
	})
end

--we need to do this to override the default damage mechanics
local punch_timers = {}
minetest.register_on_joinplayer(function(player)
	local name = player:get_player_name()
	punch_timers[name] = 0
end)

minetest.register_globalstep(function(dtime)
	for _,player in ipairs(minetest.get_connected_players()) do
		local name = player:get_player_name()
		--limit this so the game engine isn't calculating huge floats
		if punch_timers[name] and punch_timers[name] <= 10 then
			punch_timers[name] = punch_timers[name] + dtime
		end
	end
end)

--this throws the player when they're punched and activates the custom damage mechanics
minetest.register_on_punchplayer(function(player, hitter, time_from_last_punch, tool_capabilities, dir, damage)
	local name = player:get_player_name()
	local hurt = tool_capabilities.damage_groups.damage
	local hp = player:get_hp()
	if punch_timers[name] > 0.8 and hp > 0 then
		if hitter:is_player() then
			local puncher_vel = hitter:get_player_velocity().y
			if puncher_vel < 0 then
				hurt = hurt * 1.5
				critical = true
				do_critical_particles(player:get_pos())
				minetest.sound_play("critical", {pos=player:get_pos(), gain = 0.1, max_hear_distance = 16,pitch = math.random(80,100)/100})
			end
		end

		dir = vector.multiply(dir,10)
		local vel = player:get_player_velocity()
		dir.y = 0
		if vel.y <= 0 then
			dir.y = 7
		end
		punch_timers[name] = 0
		player:add_player_velocity(dir)
		player:set_hp(hp-hurt)
	end
end)