Add lava environment sound (#2683)

mods/env_sounds/README.txt

@@ -11,3 +11,7 @@ Authors of media (sounds)
 Yuval (CC0 1.0)
 https://freesound.org/people/Yuval/sounds/197023/
   env_sounds_water.*.ogg
+
+Halion (CC0 1.0)
+https://freesound.org/people/Halion/sounds/17785/
+  env_sounds_lava.*.ogg

mods/env_sounds/init.lua

 -- Parameters
 
-local radius = 8 -- Water node search radius around player
+-- Node search radius around player
+local radius = 8
+
+local allsounds = {
+	["env_sounds_water"] = {
+		trigger = {"default:water_flowing", "default:river_water_flowing"},
+		base_volume = 0.04,
+		max_volume = 0.4,
+		per_node = 0.004,
+	},
+	["env_sounds_lava"] = {
+		trigger = {"default:lava_source", "default:lava_flowing"},
+		base_volume = 0,
+		max_volume = 0.6,
+		per_node = {
+			["default:lava_source"] = 0.008,
+			["default:lava_flowing"] = 0.002,
+		},
+	},
+}
+
+if minetest.settings:get_bool("river_source_sounds") then
+	table.insert(allsounds["env_sounds_water"].trigger,
+		"default:river_water_source")
+end
+
 
--- End of parameters
+-- Cache the union of all trigger nodes
 
+local cache_triggers = {}
 
-local river_source_sounds = minetest.settings:get_bool("river_source_sounds")
+for sound, def in pairs(allsounds) do
+	for _, name in ipairs(def.trigger) do
+		table.insert(cache_triggers, name)
+	end
+end
 
 
 -- Update sound for player
@@ -13,39 +43,57 @@ local river_source_sounds = minetest.settings:get_bool("river_source_sounds")
 local function update_sound(player)
 	local player_name = player:get_player_name()
 	local ppos = player:get_pos()
+	ppos = vector.add(ppos, player:get_properties().eye_height)
 	local areamin = vector.subtract(ppos, radius)
 	local areamax = vector.add(ppos, radius)
-	local water_nodes = {"default:water_flowing", "default:river_water_flowing"}
-	if river_source_sounds then
-		table.insert(water_nodes, "default:river_water_source")
-	end
-	local wpos, _ = minetest.find_nodes_in_area(areamin, areamax, water_nodes)
-	local waters = #wpos
-	if waters == 0 then
+
+	local pos = minetest.find_nodes_in_area(areamin, areamax, cache_triggers, true)
+	if next(pos) == nil then -- If table empty
 		return
 	end
-
-	-- Find average position of water positions
-	local wposav = vector.new()
-	for _, pos in ipairs(wpos) do
-		wposav.x = wposav.x + pos.x
-		wposav.y = wposav.y + pos.y
-		wposav.z = wposav.z + pos.z
+	for sound, def in pairs(allsounds) do
+		-- Find average position
+		local posav = {0, 0, 0}
+		local count = 0
+		for _, name in ipairs(def.trigger) do
+			if pos[name] then
+				for _, p in ipairs(pos[name]) do
+					posav[1] = posav[1] + p.x
+					posav[2] = posav[2] + p.y
+					posav[3] = posav[3] + p.z
+				end
+				count = count + #pos[name]
+			end
+		end
+
+		if count > 0 then
+			posav = vector.new(posav[1] / count, posav[2] / count,
+				posav[3] / count)
+
+			-- Calculate gain
+			local gain = def.base_volume
+			if type(def.per_node) == 'table' then
+				for name, multiplier in pairs(def.per_node) do
+					if pos[name] then
+						gain = gain + #pos[name] * multiplier
+					end
+				end
+			else
+				gain = gain + count * def.per_node
+			end
+			gain = math.min(gain, def.max_volume)
+
+			minetest.sound_play(sound, {
+				pos = posav,
+				to_player = player_name,
+				gain = gain,
+			}, true)
+		end
 	end
-	wposav = vector.divide(wposav, waters)
-
-	minetest.sound_play(
-		"env_sounds_water",
-		{
-			pos = wposav,
-			to_player = player_name,
-			gain = math.min(0.04 + waters * 0.004, 0.4),
-		}
-	)
 end
 
 
--- Update sound 'on joinplayer'
+-- Update sound when player joins
 
 minetest.register_on_joinplayer(function(player)
 	update_sound(player)