portalgun/scripts/gravityuse.lua

portalgun_power = {}
portalgun_power_tmp_power = 0

function portalgun_gravity(itemstack, user, pointed_thing)
    local ob = pointed_thing.ref
    local at = ob:get_attach()
    if at and at:get_luaentity() and at:get_luaentity().portalgun_power then
        ob:set_detach()
        local target = at:get_luaentity().target
        if target and target:get_luaentity() and (target:get_luaentity().itemstring or target:get_luaentity().wsc) then
            target:set_velocity({x = 0, y = -1, z = 0})
            target:set_acceleration({x = 0, y = -8, z = 0})
        end
        return itemstack
    end
    if not ob:get_attach() and (ob:is_player() or (ob:get_luaentity() and ob:get_luaentity().powerball ~= 1)) then
        --if 4 blocks or closer to player
        if vector.distance(ob:get_pos(), user:get_pos()) < 4 then
            portalgun_power.user = user
            portalgun_power.target = ob
            if ob:is_player() then
                portalgun_power.player = 1
            end
            local m = minetest.add_entity(ob:get_pos(), "portalgun:power")
            ob:set_attach(m, "", {x = 0, y = 0, z = 0}, {x = 0, y = 0, z = 0})
            return itemstack
        end
    end

    return itemstack
end

minetest.register_entity(
    "portalgun:power",
    {
        hp_max = 100,
        physical = false,
        weight = 0,
        collisionbox = {-0.2, -0.2, -0.2, 0.2, 0.2, 0.2},
        visual = "sprite",
        visual_size = {x = 1, y = 1},
        textures = {"portalgun_gravity.png"},
        spritediv = {x = 1, y = 1},
        is_visible = true,
        makes_footstep_sound = false,
        automatic_rotate = 0,
        timer = 0,
        time = 0.1,
        portalgun_power = 1,
        portalgun = 1,
        lifelime = 100,
        on_activate = function(self, staticdata)
            if portalgun_power.user then
                self.user = portalgun_power.user
                self.target = portalgun_power.target
                self.player = portalgun_power.player
                portalgun_power = {}
            else
                self.object:remove()
            end
        end,
        on_punch = function(self, puncher, time_from_last_punch, tool_capabilities, dir)
            if self.target and self.target:get_attach() then
                self.target:set_detach()
                self.target:set_hp(0)
            end
        end,
        on_step = function(self, dtime)
            self.timer = self.timer + dtime
            if self.timer < self.time then
                return self
            end
            self.timer = 0
            if self.target == nil or (not self.target:get_attach()) then
                self.object:set_hp(0)
                if self.sound then
                    minetest.sound_stop(self.sound)
                end
            end
            if self.player then
                self.lifelime = self.lifelime - 1
                if self.lifelime < 0 then
                    self.target:set_detach()
                    return self
                end
            end
            local pos = self.user:get_pos()
            if pos == nil then
                return self
            end
            pos.y = pos.y + 1.6
            local dir = self.user:get_look_dir()
            local npos = {x = pos.x + (dir.x * 2), y = pos.y + (dir.y * 2), z = pos.z + (dir.z * 2)}
            if minetest.registered_nodes[minetest.get_node(npos).name].walkable then
                return self
            end
            self.object:move_to(npos)
            return self
        end
    }
)

minetest.register_entity(
    "portalgun:power2",
    {
        hp_max = 100,
        physical = true,
        weight = 10,
        collisionbox = {-0.35, 0, -0.35, 0.35, 1, 0.35},
        visual = "sprite",
        visual_size = {x = 1, y = 1},
        textures = {"portalgun_gravity.png"},
        spritediv = {x = 1, y = 1},
        is_visible = true,
        makes_footstep_sound = false,
        automatic_rotate = 0,
        timer = 0,
        time = 0.025,
        portalgun_power = 1,
        portalgun = 1,
        lifelime = 1000,
        v = 0.3,
        ltime = 0,
        on_activate = function(self, staticdata)
            if portalgun_power.user then
                self.user = portalgun_power.user
                self.target = portalgun_power.target
                self.ltime = portalgun_power_tmp_power
                portalgun_power = {}
            else
                self.object:remove()
            end
        end,
        on_step = function(self, dtime)
            local pos = self.object:get_pos()
            local v = self.object:get_velocity()
            local v2 = {x = v.x - self.v, y = (v.y - self.v) * 0.99, z = v.z - self.v}

            if v2.x < 0.5 and v2.x > -0.5 then
                v2.x = 0
            end
            if v2.y < 0.5 and v2.y > -0.5 then
                v2.y = 0
            end
            if v2.z < 0.5 and v2.z > -0.5 then
                v2.z = 0
            end

            self.object:set_velocity(v2)
            self.ltime = self.ltime - self.v

            if self.ltime < self.v or (v2.x + v2.y + v2.z == 0) then
                self.lifelime = -1
            end

            local nexpos = {x = pos.x + (v.x * 0.05), y = pos.y + (v.y * 0.05) + 1, z = pos.z + (v.z * 0.05)}
            if minetest.registered_nodes[minetest.get_node(nexpos).name].walkable then
                self.lifelime = -1
            end

            self.lifelime = self.lifelime - 1
            if self.lifelime < 0 then
                self.target:set_detach()
            end

            if self.target == nil or (not self.target:get_attach()) then
                self.object:set_hp(0)
                return self
            end
            return self
        end
    }
)