add random planar velocity when stopped

this seems to almost solve the problem of random standing.

mods/ENTITIES/mcl_mobs/api.lua

@@ -2244,7 +2244,14 @@ local follow_flop = function(self)
 
 			return
 		elseif self.state == "flop" then
-			self.state = "stand"
+			if not is_glider(self) then
+				self.state = "stand"
+				set_animation(self, "stand")
+			else
+				self.state = "walk"
+				set_animation(self, "walk")
+				return
+			end
 			self.object:set_acceleration({x = 0, y = 0, z = 0})
 			set_velocity(self, 0)
 		end
@@ -2490,10 +2497,14 @@ local do_states = function(self, dtime)
 		or random(1, 100) <= 30
 		or ( (self.fly and not self.keep_flying)
 		or not self.fly ) then
-
-			set_velocity(self, 0)
-			self.state = "stand"
-			set_animation(self, "stand")
+			if not is_glider(self) then
+				self.state = "stand"
+				set_animation(self, "stand")
+				set_velocity(self, 0)
+			else
+				self.state = "walk"
+				set_animation(self, "walk")
+			end
 			local yaw = self.object:get_yaw() or 0
 			yaw = set_yaw(self, yaw + 0.78, 8)
 		else
@@ -2519,9 +2530,14 @@ local do_states = function(self, dtime)
 		if self.runaway_timer > 5
 		or is_at_cliff_or_danger(self) then
 			self.runaway_timer = 0
-			set_velocity(self, 0)
-			self.state = "stand"
-			set_animation(self, "stand")
+			if not is_glider(self) then
+				self.state = "stand"
+				set_animation(self, "stand")
+				set_velocity(self, 0)
+			else
+				self.state = "walk"
+				set_animation(self, "walk")
+			end
 			local yaw = self.object:get_yaw() or 0
 			yaw = set_yaw(self, yaw + 0.78, 8)
 		else
@@ -2542,9 +2558,14 @@ local do_states = function(self, dtime)
 		or self.attack:get_hp() <= 0
 		or (self.attack:is_player() and mcl_mobs.invis[ self.attack:get_player_name() ]) then
 
-			self.state = "stand"
-			set_velocity(self, 0)
-			set_animation(self, "stand")
+			if not is_glider(self) then
+				self.state = "stand"
+				set_animation(self, "stand")
+				set_velocity(self, 0)
+			else
+				self.state = "walk"
+				set_animation(self, "walk")
+			end
 			self.attack = nil
 			self.v_start = false
 			self.timer = 0
@@ -3391,7 +3412,11 @@ local mob_staticdata = function(self)
 	self.remove_ok = true
 	self.attack = nil
 	self.following = nil
-	self.state = "stand"
+	if not is_glider(self) then
+		self.state = "stand"
+	else
+		self.state = "walk"
+	end
 
 	local tmp = {}
 
@@ -3582,21 +3607,26 @@ end
 
 local function check_ground(self) --return true if too close to the ground
 	local p = self.object:get_pos()
-	local n = minetest.find_nodes_in_area_under_air(vector.offset(p,0,-self.desired_altitude-1,0),vector.offset(p,0,0,0),{"group:solid"})
+	local n = minetest.find_nodes_in_area_under_air(vector.offset(p,0,-self.desired_altitude-1,0),vector.offset(p,0,0,0),{"group:solid","group:liquid"})
 	if #n > 0 then
 		return true
 	end
 end
 
+local function get_random_velocity(self)
+	local v = self.object:get_velocity()
+	return vector.new(math.random(self.walk_velocity),v.y,math.random(self.walk_velocity))
+end
+
 local function descend(self)
 	local v = self.object:get_velocity()
 	local gs = get_speed_over_ground(self)
 	local r = math.max(math.abs(self.fall_speed) - gs,1)
 	--minetest.log("descend "..tostring(r) .. " vel "..tostring(v.y).. " rate "..tostring(r))
 	if v.y > self.fall_speed then
-		self.object:set_velocity(vector.new(v.x,-r,v.z))
+		--self.object:set_velocity(vector.new(v.x,-r,v.z))
+		self.object:add_velocity(vector.new(0,-r/10,0))
 	end
-	
 end
 
 local function climb(self)
@@ -3613,6 +3643,12 @@ end
 local function check_flight(self,dtime)
 	if self.floater or not self.fly then return end --floaters don't need altitdude adjustment
 	--self.state = "walk"
+	local gs = get_speed_over_ground(self)
+	if gs < 1 then
+		local y = self.object:get_yaw()
+		self.object:set_yaw((y + math.random(-30,30)) % 360)
+		set_velocity(self,math.random(1,self.walk_velocity))
+	end
 	if not self.flap_timer and check_ground(self) then
 		climb(self)
 		self.flap_timer = 0
@@ -3777,8 +3813,13 @@ local mob_step = function(self, dtime)
 	if is_at_water_danger(self) and self.state ~= "attack" then
 		if random(1, 10) <= 6 then
 			set_velocity(self, 0)
-			self.state = "stand"
-			set_animation(self, "stand")
+			if not is_glider(self) then
+				self.state = "stand"
+				set_animation(self, "stand")
+			else
+				self.state = "walk"
+				set_animation(self, "walk")
+			end
 			yaw = yaw + random(-0.5, 0.5)
 			yaw = set_yaw(self, yaw, 8)
 		end
@@ -3827,9 +3868,14 @@ local mob_step = function(self, dtime)
 	follow_flop(self)
 
 	if is_at_cliff_or_danger(self) then
-			set_velocity(self, 0)
-			self.state = "stand"
-			set_animation(self, "stand")
+			if not is_glider(self) then
+				set_velocity(self, 0)
+				self.state = "stand"
+				set_animation(self, "stand")
+			else
+				self.state = "walk"
+				set_animation(self, "walk")
+			end
 			local yaw = self.object:get_yaw() or 0
 			yaw = set_yaw(self, yaw + 0.78, 8)
 	end