simple-shooter-game/mods/game/ctf_guns/grenades/grenades.lua

local function remove_flora(pos, radius)
	local pos1 = vector.subtract(pos, radius)
	local pos2 = vector.add(pos, radius)

	for _, p in ipairs(minetest.find_nodes_in_area(pos1, pos2, "group:flora")) do
		if vector.distance(pos, p) <= radius then
			minetest.remove_node(p)
		end
	end
end

local function check_hit(pos1, pos2, obj)
	local ray = minetest.raycast(pos1, pos2, true, false)
	local hit = ray:next()

	while hit and hit.type == "node" and vector.distance(pos1, hit.under) <= 1.6 do
		hit = ray:next()
	end

	if hit and hit.type == "object" and hit.ref == obj then
		return true
	end
end

local fragdef = {
   description = "Frag grenade (Kills anyone near blast)",
   image = "grenades_frag.png",
   explode_radius = 10,
   explode_damage = 26,
   on_collide = function(def, obj)
      return true
   end,
   on_explode = function(def, pos, name)
      if not name or not pos then return end

      local player = minetest.get_player_by_name(name)
      if not player then return end


      local radius = def.explode_radius

      minetest.add_particlespawner({
	    amount = 20,
	    time = 0.5,
	    minpos = vector.subtract(pos, radius),
	    maxpos = vector.add(pos, radius),
	    minvel = {x = 0, y = 5, z = 0},
	    maxvel = {x = 0, y = 7, z = 0},
	    minacc = {x = 0, y = 1, z = 0},
	    maxacc = {x = 0, y = 1, z = 0},
	    minexptime = 0.3,
	    maxexptime = 0.6,
	    minsize = 7,
	    maxsize = 10,
	    collisiondetection = true,
	    collision_removal = false,
	    vertical = false,
	    texture = "grenades_smoke.png",
      })

      minetest.add_particle({
	    pos = pos,
	    velocity = {x=0, y=0, z=0},
	    acceleration = {x=0, y=0, z=0},
	    expirationtime = 0.3,
	    size = 15,
	    collisiondetection = false,
	    collision_removal = false,
	    object_collision = false,
	    vertical = false,
	    texture = "grenades_boom.png",
	    glow = 10
      })

      minetest.sound_play("grenades_explode", {
			     pos = pos,
			     gain = 1.0,
			     max_hear_distance = 64,
      })

      remove_flora(pos, radius/2)

      for _, v in pairs(minetest.get_objects_inside_radius(pos, radius)) do
	 if v.punch ~= nil and v:get_hp() > 0 then
	    local footpos = vector.offset(v:get_pos(), 0, 0.1, 0)
	    local e_height = 0
	    
	    if v:get_properties().eye_height ~= nil then
	       e_height = v:get_properties().eye_height
	    else
	       e_height = 1
	    end
	    
	    local headpos = vector.offset(v:get_pos(), 0, e_height, 0)
	    local footdist = vector.distance(pos, footpos)
	    local headdist = vector.distance(pos, headpos)
	    local target_head = false

	    if footdist >= headdist then
	       target_head = true
	    end

	    local hit_pos1 = check_hit(pos, target_head and headpos or footpos, v)

	    -- Check the closest distance, but if that fails try targeting the farther one
	    if hit_pos1 or check_hit(pos, target_head and footpos or headpos, v) then
	       v:punch(player, 1, {
			  punch_interval = 1,
			  damage_groups = {
			     grenade = 1,
			     fleshy = def.explode_damage - ( (radius/3) * (target_head and headdist or footdist) )
			  }
				  }, nil)
	    end
	 end
      end
   end,
}

grenades.register_grenade("grenades:frag", fragdef)

local fragdef_sticky = table.copy(fragdef)
fragdef_sticky.description = "Sticky Frag grenade (Sticks to surfaces)"
fragdef_sticky.image = "grenades_frag_sticky.png"
fragdef_sticky.on_collide = function() return false end
grenades.register_grenade("grenades:frag_sticky", fragdef_sticky)

-- Smoke Grenade

local sounds = {}
local SMOKE_GRENADE_TIME = 30
grenades.register_grenade("grenades:smoke", {
	description = "Smoke grenade (Generates smoke around blast site)",
	image = "grenades_smoke_grenade.png",
	on_collide = function()
		return true
	end,
	on_explode = function(def, pos, pname)
		local player = minetest.get_player_by_name(pname)
		if not player or not pos then return end

		local pteam = ctf_teams.get(pname)

		if pteam then
			local fpos = ctf_map.current_map.teams[pteam].flag_pos

			if not fpos then return end

			if vector.distance(pos, fpos) <= 15 then
				minetest.chat_send_player(pname, "You can't explode smoke grenades so close to your flag!")
				player:get_inventory():add_item("main", "grenades:smoke")
				return
			end
		end

		minetest.sound_play("grenades_glasslike_break", {
			pos = pos,
			gain = 1.0,
			max_hear_distance = 32,
		})

		local hiss = minetest.sound_play("grenades_hiss", {
			pos = pos,
			gain = 1.0,
			loop = true,
			max_hear_distance = 32,
		})
		sounds[hiss] = true

		minetest.after(SMOKE_GRENADE_TIME, function()
			sounds[hiss] = nil
			minetest.sound_stop(hiss)
		end)

		for i = 0, 5, 1 do
			minetest.add_particlespawner({
				amount = 40,
				time = SMOKE_GRENADE_TIME + 3,
				minpos = vector.subtract(pos, 2),
				maxpos = vector.add(pos, 2),
				minvel = {x = 0, y = 2, z = 0},
				maxvel = {x = 0, y = 3, z = 0},
				minacc = {x = 1, y = 0.2, z = 1},
				maxacc = {x = 1, y = 0.2, z = 1},
				minexptime = 1,
				maxexptime = 1,
				minsize = 125,
				maxsize = 140,
				collisiondetection = false,
				collision_removal = false,
				vertical = false,
				texture = "grenades_smoke.png",
			})
		end
	end,
	particle = {
		image = "grenades_smoke.png",
		life = 1,
		size = 4,
		glow = 0,
		interval = 0.3,
	}
})