VoxeLibre/mods/ITEMS/mcl_potions/lingering.lua

local lingering_image = function(colorstring, opacity)
	if not opacity then
		opacity = 127
	end
	return "mcl_potions_splash_overlay.png^[colorize:"..colorstring..":"..tostring(opacity).."^mcl_potions_splash_bottle.png"
end


local lingering_effect_at = {}

local function add_lingering_effect(pos, color, def)

	lingering_effect_at[pos] = {color = color, timer = 30, def = def}

	local timer = 0

	minetest.register_globalstep(function(dtime)

		timer = timer + dtime

		if timer >= 0.5 then

			for pos, vals in pairs(lingering_effect_at) do

				if lingering_effect_at[pos] then

					lingering_effect_at[pos].timer = lingering_effect_at[pos].timer - timer

					if lingering_effect_at[pos].timer > 0 then

						local d = 3 * (lingering_effect_at[pos].timer / 30.0)

						minetest.add_particlespawner({
														amount = 5 * math.ceil(d)^2,
														time = 1,
														minpos = {x=pos.x-d, y=pos.y+0.5, z=pos.z-d},
														maxpos = {x=pos.x+d, y=pos.y+1, z=pos.z+d},
														minvel = {x=-0.5, y=0, z=-0.5},
														maxvel = {x=0.5, y=0.5, z=0.5},
														minacc = {x=-0.2, y=0, z=-0.2},
														maxacc = {x=0.2, y=.05, z=0.2},
														minexptime = 1,
														maxexptime = 2,
														minsize = 2,
														maxsize = 4,
														collisiondetection = true,
														vertical = false,
														texture = "mcl_potions_sprite.png^[colorize:"..lingering_effect_at[pos].color..":127",
													})

						for i, obj in ipairs(minetest.get_objects_inside_radius(pos, math.ceil(d+1))) do

							obj = obj or obj:get_luaentity()

							if minetest.is_player(obj) or obj._cmi_is_mob then

								lingering_effect_at[pos].def.potion_fun(obj)
								lingering_effect_at[pos].timer = lingering_effect_at[pos].timer / 2

							end
						end

					else
						lingering_effect_at[pos] = nil
					end
				end
			end
			timer = 0
		end
	end)

end



local function register_lingering(name, descr, color, def)

    local id = "mcl_potions:"..name.."_lingering"
    minetest.register_craftitem(id, {
        description = descr,
        inventory_image = lingering_image(color),
        on_use = function(item, placer, pointed_thing)
            local velocity = 10
            local dir = placer:get_look_dir();
            local pos = placer:getpos();
            local obj = minetest.env:add_entity({x=pos.x+dir.x,y=pos.y+2+dir.y,z=pos.z+dir.z}, id.."_flying")
            obj:setvelocity({x=dir.x*velocity,y=dir.y*velocity,z=dir.z*velocity})
            obj:setacceleration({x=0, y=-9.8, z=0})
			if not minetest.settings:get_bool("creative_mode") then
				item:take_item()
			end
            return item
        end,
		stack_max = 1,
    })

    local w = 0.7

    minetest.register_entity(id.."_flying",{
        textures = {lingering_image(color)},
		hp_max = 1,
		visual_size = {x=w/2,y=w/2},
		collisionbox = {0,0,0,0,0,0},
        on_step = function(self, dtime)
          local pos = self.object:getpos()
          local node = minetest.get_node(pos)
          local n = node.name
					local d = 2
          			if n ~= "air"  or mcl_potions.is_obj_hit(self, pos) then
						minetest.sound_play("mcl_potions_breaking_glass", {pos = pos, max_hear_distance = 16, gain = 1})
						add_lingering_effect(pos, color, def)
            		 	self.object:remove()
					end
        end,
    })
end

register_lingering("water", "Lingering Potion", "#0000FF", {
    potion_fun = function(player)  end,
})

register_lingering("river_water", "Lingering Potion", "#0000FF", {
    potion_fun = function(player)  end,
})

register_lingering("awkward", "Lingering Awkward Potion", "#0000FF", {
    potion_fun = function(player)  end,
})

register_lingering("mundane", "Lingering Mundane Potion", "#0000FF", {
    potion_fun = function(player)  end,
})

register_lingering("thick", "Lingering Thick Potion", "#0000FF", {
    potion_fun = function(player)  end,
})

register_lingering("healing", "Lingering Healing", "#AA0000", {
    potion_fun = function(player) player:set_hp(player:get_hp() + 3*0.5) end,
})

register_lingering("healing_2", "Lingering Healing II", "#DD0000", {
    potion_fun = function(player, redx) player:set_hp(player:get_hp() + 6*0.5) end,
})

register_lingering("harming", "Lingering Harming", "#660099", {
    potion_fun = function(player, redx) mcl_potions.healing_func(player, -4*0.5) end,
})

register_lingering("harming_2", "Lingering Harming II", "#330066", {
    potion_fun = function(player, redx) mcl_potions.healing_func(player, -6*0.5) end,
})

register_lingering("leaping", "Lingering Leaping", "#00CC33", {
		potion_fun = function(player, redx) mcl_potions.leaping_func(player, 1.2, 135*0.25) end
})

register_lingering("leaping_2", "Lingering Leaping II", "#00EE33", {
		potion_fun = function(player, redx) mcl_potions.leaping_func(player, 1.4, 135*0.25) end
})

register_lingering("leaping_plus", "Lingering Leaping +", "#00DD33", {
		potion_fun = function(player, redx) mcl_potions.leaping_func(player, 1.2, 360*0.25) end
})

register_lingering("swiftness", "Lingering Swiftness", "#009999", {
		potion_fun = function(player, redx) mcl_potions.swiftness_func(player, 1.2, 135*0.25) end
})

register_lingering("swiftness_2", "Lingering Swiftness II", "#00BBBB", {
		potion_fun = function(player, redx) mcl_potions.swiftness_func(player, 1.4, 135*0.25) end
})

register_lingering("swiftness_plus", "Lingering Swiftness +", "#00BBBB", {
		potion_fun = function(player, redx) mcl_potions.swiftness_func(player, 1.2, 360*0.25) end
})

register_lingering("slowness", "Lingering Slowness ", "#000080", {
		potion_fun = function(player, redx) mcl_potions.swiftness_func(player, 0.85, 68*0.25) end
})

register_lingering("slowness_plus", "Lingering Slowness +", "#000066", {
		potion_fun = function(player, redx) mcl_potions.swiftness_func(player, 0.85, 180*0.25) end
})

register_lingering("poison", "Lingering Poison", "#335544", {
		potion_fun = function(player, redx) mcl_potions.poison_func(player, 2.5, 45*0.25) end
})

register_lingering("poison_2", "Lingering Poison II", "#446655", {
		potion_fun = function(player, redx) mcl_potions.poison_func(player, 1.2, 21*0.25) end
})

register_lingering("poison_plus", "Lingering Poison +", "#557766", {
		potion_fun = function(player, redx) mcl_potions.poison_func(player, 2.5, 90*0.25) end
})

register_lingering("regeneration", "Lingering Regeneration", "#A52BB2", {
		potion_fun = function(player, redx) mcl_potions.regeneration_func(player, 2.5, 45*0.25) end
})

register_lingering("regeneration_2", "Lingering Regeneration II", "#B52CC2", {
		potion_fun = function(player, redx) mcl_potions.regeneration_func(player, 1.2, 21*0.25) end
})

register_lingering("regeneration_plus", "Lingering Regeneration +", "#C53DD3", {
		potion_fun = function(player, redx) mcl_potions.regeneration_func(player, 2.5, 90*0.25) end
})

register_lingering("invisibility", "Lingering Invisibility", "#B0B0B0", {
	potion_fun = function(player, redx) mcl_potions.invisiblility_func(player, 135*0.25) end
})

register_lingering("invisibility_plus", "Lingering Invisibility +", "#A0A0A0", {
	potion_fun = function(player, redx) mcl_potions.invisiblility_func(player, 300*0.25) end
})

register_lingering("weakness", "Lingering Weakness", "#6600AA", {
	potion_fun = function(player, redx) mcl_potions.weakness_func(player, 1.2, 68*0.25) end
})

register_lingering("weakness_plus", "Lingering Weakness +", "#7700BB", {
	potion_fun = function(player, redx) mcl_potions.weakness_func(player, 1.4, 180*0.25) end
})