Add API function for wind speed

API.md

@@ -5,7 +5,8 @@ get a list of all flags, and set and get the flag of flag pole nodes.
 
 ## Functions
 
-### `pride_flags.add_flag = function(name)`
+### `pride_flags.add_flag(name)`
+
 Add a new flag to the game. `name` is the flag identifier.
 There *must* exist a texture with the name `prideflag_<name>.png`.
 The texture *should* have an aspect ratio of 1.3.
@@ -21,16 +22,43 @@ added.
 
 Returns `true` on success and `false` on failure.
 
-### `pride_flags.get_flags = function()`
+### `pride_flags.get_flags()`
+
 Returns a list of all available flag identifiers. The flags
 are sorted by selection order.
 
-### `pride_flags.set_flag_at = function(pos, flag_name)`
+### `pride_flags.set_flag_at(pos, flag_name)`
+
 Sets the flag at an upper mast node at position `pos` to the flag `flag_name`.
 The node at `pos` *must* be `pride_flags:upper_mast`.
 Returns `true` on success and `false` otherwise.
 
-### `pride_flags.get_flag_at = function(pos)`
+### `pride_flags.get_flag_at(pos)`
+
 Returns the currently used flag at the upper mast node at position `pos`.
 The node at `pos` *must* be `pride_flags:upper_mast`.
 Returns a string on success and `nil` otherwise.
+
+### `pride_flags.get_wind(pos)`
+
+Returns the current wind strength at pos. The wind strength determines how
+fast a flag at pos would be waving at the time this function was called.
+
+This function will be called from time to time by the mod to update
+the flag waving speed of flags. It is called for every flag once about
+every 115 seconds (plusminus 10 seconds).
+
+This function is predefined in this mod by pseudorandomly changing the wind
+strength over time using a Perlin noise. By default, the wind strength is
+only controlled by the current time; the position is ignored.
+
+This function can be overwritten by mods to define your own wind algorithm.
+You can do whatever in this function, you only need to return a number in
+the end. The number should be roughly in the range between 0 and 50.
+
+This is how the wind strength affects the flag waving speed:
+
+* wind < 10: slow
+* 10 < wind < 20: medium
+* 20 < wind < 40: fast
+* wind > 40: very fast

init.lua

@@ -183,15 +183,9 @@ minetest.register_entity( "pride_flags:wavingflag", {
 	end,
 
 	reset_animation = function ( self, initial )
-		local coords = { x = os.time( ) % 65535, y = 0 }
-		local cur_wind
-		if old_get2d then
-			cur_wind = wind_noise:get2d(coords)
-		else
-			cur_wind = wind_noise:get_2d(coords)
-		end
-		cur_wind = cur_wind * 30 + 30
-		minetest.log("verbose", "[pride_flags] Current wind: " .. cur_wind)
+		local pos = self.object:get_pos( )
+		local cur_wind = pride_flags.get_wind( pos )
+		minetest.log("verbose", "[pride_flags] Current wind at "..minetest.pos_to_string(pos, 1)..": " .. cur_wind)
 		local anim_speed
 		local wave_sound
 
@@ -678,4 +672,19 @@ pride_flags.get_flag_at = function( pos )
 	end
 end
 
+-- Returns the wind strength at pos.
+-- Can be overwritten by mods.
+pride_flags.get_wind = function( pos )
+	-- The default wind function ignores pos.
+	-- Returns a wind between ca. 0 and 55
+	local coords = { x = os.time( ) % 65535, y = 0 }
+	local cur_wind
+	if old_get2d then
+		cur_wind = wind_noise:get2d(coords)
+	else
+		cur_wind = wind_noise:get_2d(coords)
+	end
+	cur_wind = cur_wind * 30 + 30
+	return cur_wind
+end