abstract the particle spawner start/stop functions

homedecor/handlers/water_particles.lua

@@ -0,0 +1,113 @@
+-- variables taken by the start... function
+--
+-- pos and node are as usual, from e.g. on_rightclick.
+--
+-- in the { particledef } table:
+--
+-- outletx/y/z are the exact coords of the starting point
+--     for the spawner, relative to the center of the node
+--
+-- velocityx/y are the speed of the particles,
+--     relative to a node placed while looking north (facedir 0)
+--
+-- spread is the radius from the starting point,
+-- along X and Z only, to randomly spawn particles.
+--
+-- soundname is the filename (without .ogg) of the sound file
+-- to be played along with the particle stream
+
+function homedecor.start_particle_spawner(pos, node, particledef, soundname)
+
+	local this_spawner_meta = minetest.get_meta(pos)
+	local id = this_spawner_meta:get_int("active")
+	local s_handle = this_spawner_meta:get_int("sound")
+
+	if id ~= 0 then
+		if s_handle then
+			minetest.after(0, function(s_handle)
+				minetest.sound_stop(s_handle)
+			end, s_handle)
+		end
+		minetest.delete_particlespawner(id)
+		this_spawner_meta:set_int("active", nil)
+		this_spawner_meta:set_int("sound", nil)
+		return
+	end
+
+	local fdir = node.param2
+
+	if fdir and fdir < 4 and (not id or id == 0) then
+
+		local outletx    = particledef.outlet_x
+		local outlety    = particledef.outlet_y
+		local outletz    = particledef.outlet_z
+		local velocityx  = particledef.velocity_x
+		local velocityz  = particledef.velocity_z
+		local spread     = particledef.spread
+
+		local minx_t = {  outletx - spread, -outletz - spread, outletx - spread, outletz - spread }
+		local maxx_t = {  outletx + spread, -outletz + spread, outletx + spread, outletz + spread }
+		local minz_t = { -outletz - spread,  outletx - spread, outletz - spread, outletx - spread }
+		local maxz_t = { -outletz + spread,  outletx + spread, outletz + spread, outletx + spread }
+
+		local minvelx_t = { velocityx.min, velocityz.min, -velocityx.max, -velocityz.max }
+		local maxvelx_t = { velocityx.max, velocityz.max, -velocityx.min, -velocityz.min }
+		local minvelz_t = { velocityz.min, velocityx.min, -velocityz.max,  velocityx.min }
+		local maxvelz_t = { velocityz.max, velocityx.max, -velocityz.min,  velocityx.max }
+
+		local minx = minx_t[fdir + 1]
+		local maxx = maxx_t[fdir + 1]
+		local minz = minz_t[fdir + 1]
+		local maxz = maxz_t[fdir + 1]
+
+		local minvelx = minvelx_t[fdir + 1]
+		local minvelz = minvelz_t[fdir + 1]
+		local maxvelx = maxvelx_t[fdir + 1]
+		local maxvelz = maxvelz_t[fdir + 1]
+
+		id = minetest.add_particlespawner({
+			amount = 60,
+			time = 0,
+			collisiondetection = true,
+			minpos = {x=pos.x - minx, y=pos.y + outlety, z=pos.z - minz},
+			maxpos = {x=pos.x - maxx, y=pos.y + outlety, z=pos.z - maxz},
+			minvel = {x = minvelx, y=-2, z = minvelz},
+			maxvel = {x = maxvelx, y=-2, z = maxvelz},
+			minacc = {x=0, y=0, z=0},
+			maxacc = {x=0, y=-0.05, z=0},
+			minexptime = 2,
+			maxexptime = 4,
+			minsize = 0.5,
+			maxsize = 1,
+			texture = "homedecor_water_particle.png",
+		})
+		s_handle = minetest.sound_play(soundname, {
+			pos = pos,
+			max_hear_distance = 5,
+			loop = true
+		})
+		this_spawner_meta:set_int("active", id)
+		this_spawner_meta:set_int("sound", s_handle)
+		return
+	end
+end
+
+function homedecor.stop_particle_spawner(pos)
+	local this_spawner_meta = minetest.get_meta(pos)
+	local id = this_spawner_meta:get_int("active")
+	local s_handle = this_spawner_meta:get_int("sound")
+
+	if id ~= 0 then
+		minetest.delete_particlespawner(id)
+	end
+
+	if s_handle then
+		minetest.after(0, function(s_handle)
+			minetest.sound_stop(s_handle)
+		end, s_handle)
+	end
+
+	this_spawner_meta:set_int("active", nil)
+	this_spawner_meta:set_int("sound", nil)
+end
+