Complete rewrite

lib/api_utility.lua

@@ -0,0 +1,63 @@
+local mod_player_monoids = minetest.get_modpath("player_monoids") ~= nil
+local mod_playerphysics = minetest.get_modpath("playerphysics") ~= nil
+
+local utility = {}
+
+function utility.rangelim(value, min, max)
+	return math.min(math.max(value, min), max)
+end
+
+-- from https://stackoverflow.com/a/29133654
+-- merges two tables together
+-- if in conflict, b will override values of a
+function utility.merge_tables(a, b)
+	if type(a) == "table" and type(b) == "table" then
+		for k,v in pairs(b) do
+			if type(v)=="table" and type(a[k] or false)=="table" then
+				merge(a[k],v)
+			else a[k]=v end
+		end
+	end
+	return a
+end
+
+-- see https://en.wikipedia.org/wiki/Logistic_function
+function utility.logistic_growth(value, max, growth, midpoint)
+	return max / (1 + math.exp(-growth * (value - midpoint)))
+end
+
+-- generates a wave of cycle length 1
+-- maps parameters to values between 0 and 1
+-- 0 is mapped to 0 and 0.5 to 1
+function utility.normalized_cycle(value)
+	return math.cos((2 * value + 1) * math.pi) / 2 + 0.5
+end
+
+-- override player physics
+-- use utility mod if possible to avoid conflict
+function utility.add_physics(id, player, effect, value)
+	if mod_player_monoids then
+		player_monoids[effect]:add_change(player, value, id)
+	elseif mod_playerphysics then
+		playerphysics.add_physics_factor(player, effect, id, value)
+	else
+		local override = {}
+		override[effect] = value
+		player:set_physics_override(override)
+	end
+end
+
+-- reset player phsysics to normal
+function utility.remove_physics(id, player, effect)
+	if mod_player_monoids then
+		player_monoids[effect]:del_change(player, id)
+	elseif mod_playerphysics then
+		playerphysics.remove_physics_factor(player, effect, id)
+	else
+		local override = {}
+		override[effect] = 1
+		player:set_physics_override(override)
+	end
+end
+
+return utility