towers shoot n stuff

src/color.lua

@@ -5,14 +5,16 @@ COLORS = {
 
     -- tones
     WHITE               = vec4(0.8, 0.8, 0.7, 1),
-    BLACK               = vec4(0, 0, 0, 1),
+    BLACK               = vec4(0, 0, 0.02, 1),
     TRUE_BLACK          = vec4(0, 0, 0, 1),
 
+    -- non-standard hues
+    WATER               = vec4(0.12, 0.3, 0.3, 1),
+    GRASS               = vec4(0.10, 0.25, 0.10, 1),
+    DIRT                = vec4(0.22, 0.20, 0.10, 1),
+    MOUNTAIN            = vec4(0.45, 0.30, 0.20, 1),
+
     -- hues
-    BLUE_STONE          = vec4(0.12, 0.3, 0.3, 1),
-    MYRTLE              = vec4(0.10, 0.25, 0.10, 1),
-    BROWN_POD           = vec4(0.25, 0.20, 0.10, 1),
-    BOTTLE_GREEN        = vec4(0.15, 0.30, 0.20, 1),
     MAGENTA             = vec4(1, 0, 1, 1),
     TEAL                = vec4(16/255, 126/255, 124/244, 1),
     YALE_BLUE           = vec4(4/255, 75/255, 127/255, 1),

src/entity.lua

@@ -0,0 +1,64 @@
+
+ENTITY_TYPE = {
+    ENTITY      = 0,
+    MOB         = 1,
+    TOWER       = 2,
+    PROJECTILE  = 3
+}
+
+ENTITIES = {}
+--  entity structure:
+--  {
+--      TOB             - number    - time of birth, const
+--
+--      hex             - vec2      - current occupied hex, if any
+--      position        - vec2      - current pixel position of it's translate (forced parent) node
+--      update          - function  - runs every frame with itself and its index as an argument
+--      node            - node      - scene graph node
+--  }
+--
+--  mob(entity) structure:
+--  {
+--      path            - 2d table  - map of hexes to other hexes, forms a path
+--      speed           - number    - multiplier on distance travelled per frame, up to the update function to use correctly
+--  }
+--
+--  tower(entity) structure:
+--  {
+--      -- @NOTE these should probably be wrapped in a 'weapon' struct or something, so towers can have multiple weapons
+--      range           - number    - distance it can shoot
+--      last_shot_time  - number    - timestamp (seconds) of last time it shot
+--      target_index    - number    - index of entity it is currently shooting
+--  }
+--
+--  bullet/projectile structure
+--  {
+--  }
+--
+function make_and_register_entity(type_, hex, node, update)
+    local entity = {}
+
+    entity.type     = type_
+    entity.TOB      = TIME
+    entity.hex      = hex
+    entity.position = hex_to_pixel(hex)
+    entity.update   = update or function() log("unimplemented update function!") end
+    entity.node     = am.translate(entity.position) ^ node
+
+    table.insert(ENTITIES, entity)
+    WIN.scene"world":append(entity.node)
+    return entity
+end
+
+function delete_entity(index)
+    WIN.scene"world":remove(ENTITIES[index].node)
+    ENTITIES[index] = nil
+end
+
+function do_entity_updates()
+    for index,entity in pairs(ENTITIES) do
+        entity.update(entity, index)
+    end
+end
+
+

src/grid.lua

@@ -6,9 +6,10 @@ require "hexyz"
 HEX_SIZE = 20
 
 -- with 1920x1080, this is the minimal dimensions to cover the screen (65x33)
+-- @NOTE added 2 cell padding, because we terraform the very outer edge and it looks ugly
 -- odd numbers are important because we want a 'true' center
-HEX_GRID_WIDTH = 65
-HEX_GRID_HEIGHT = 33
+HEX_GRID_WIDTH = 67
+HEX_GRID_HEIGHT = 35
 HEX_GRID_DIMENSIONS = vec2(HEX_GRID_WIDTH, HEX_GRID_HEIGHT)
 
 -- leaving y == 0 makes this the center in hex coordinates
@@ -29,7 +30,6 @@ end
 
 GRID_PIXEL_DIMENSIONS = grid_pixel_dimensions()
 
-
 HEX_GRID_INTERACTABLE_REGION_PADDING = 2
 function is_interactable(tile, evenq)
     return point_in_rect(evenq, {
@@ -44,25 +44,27 @@ function is_passable(tile, mob)
     return tile.elevation > -0.5 and tile.elevation < 0.5
 end
 
--- map elevation to appropriate tile color.
+-- map elevation to appropriate color
 function color_at(elevation)
-    if elevation < -0.5 then -- lowest elevation : impassable
-        return COLORS.BLUE_STONE{ a = (elevation + 1.4) / 2 + 0.2 }
+    if elevation < -0.5 then -- lowest elevation
+        return COLORS.WATER{ a = (elevation + 1.4) / 2 + 0.2 }
 
-    elseif elevation < 0 then -- med-low elevation : passable
-        return math.lerp(COLORS.MYRTLE, COLORS.BROWN_POD, elevation + 0.5){ a = (elevation + 1.8) / 2 + 0.2 }
+    elseif elevation < 0 then -- med-low elevation
+        return math.lerp(COLORS.DIRT, COLORS.GRASS, elevation + 0.5){ a = (elevation + 1.8) / 2 + 0.2 }
 
-    elseif elevation < 0.5 then -- med-high elevation : passable
-        return math.lerp(COLORS.MYRTLE, COLORS.BROWN_POD, elevation + 0.5){ a = (elevation + 1.6) / 2 + 0.2 }
+    elseif elevation < 0.5 then -- med-high elevation
+        return math.lerp(COLORS.DIRT, COLORS.GRASS, elevation + 0.5){ a = (elevation + 1.6) / 2 + 0.2 }
 
-    elseif elevation < 1 then     -- highest elevation : impassable
-        return COLORS.BOTTLE_GREEN{ a = (elevation + 1.0) / 2 + 0.2 }
+    elseif elevation < 1 then     -- high elevation
+        return COLORS.MOUNTAIN{ ra = elevation }
 
     else
         log('bad elevation'); return vec4(0)
     end
 end
 
+-- hex_neighbours returns all coordinate positions that could be valid for a map extending infinite in all directions
+-- grid_neighbours only gets you the neighbours that are actually in the grid
 function grid_neighbours(map, hex)
     return table.filter(hex_neighbours(hex), function(_hex)
         return map.get(_hex.x, _hex.y)
@@ -76,9 +78,24 @@ function random_map(seed)
     local world = am.group():tag"world"
     for i,_ in pairs(map) do
         for j,noise in pairs(map[i]) do
-            local off = hex_to_evenq(vec2(i, j))
-            local mask = vec4(0, 0, 0, math.max(((off.x - HEX_GRID_DIMENSIONS.x/2) / HEX_GRID_DIMENSIONS.x) ^ 2
-                                             , ((-off.y - HEX_GRID_DIMENSIONS.y/2) / HEX_GRID_DIMENSIONS.y) ^ 2))
+            local evenq = hex_to_evenq(vec2(i, j))
+
+            -- check if we're on an edge -- terraform edges to be passable
+            if  evenq.x == 0 or  evenq.x == (HEX_GRID_WIDTH - 1)
+            or -evenq.y == 0 or -evenq.y == (HEX_GRID_HEIGHT - 1) then
+                noise = 0
+
+            else
+                -- scale noise to be closer to 0 the closer we are to the center
+                -- @NOTE i don't know if this 100% of the time makes the center tile passable, but it probably does 99.9+% of the time
+                local nx, ny = evenq.x/HEX_GRID_WIDTH - 0.5, -evenq.y/HEX_GRID_HEIGHT - 0.5
+                local d = math.sqrt(nx^2 + ny^2) / math.sqrt(0.5)
+                noise = noise * d^0.125 -- arbitrary, seems to work good
+            end
+
+            -- light shading on edge cells
+            local mask = vec4(0, 0, 0, math.max(((evenq.x - HEX_GRID_WIDTH/2) / HEX_GRID_WIDTH) ^ 2
+                                             , ((-evenq.y - HEX_GRID_HEIGHT/2) / HEX_GRID_HEIGHT) ^ 2))
             local color = color_at(noise) - mask
 
             local node = am.circle(hex_to_pixel(vec2(i, j)), HEX_SIZE, color, 6)
@@ -92,15 +109,6 @@ function random_map(seed)
         end
     end
 
-    -- the center of the map in some radius is always considered 'passable' terrain and is home base
-    -- terraform this area to ensure it's passable
-    -- @NOTE no idea why the y-coord doesn't need to be transformed
-    -- @TODO @FIXME also terraform the edges of the map to be passable - it is theoretically possible to get maps where mobs can be stuck from the very beginning
-    local home = spiral_map(HEX_GRID_CENTER, 3)
-    for _,hex in pairs(home) do
-        map[hex.x][hex.y].elevation = 0
-        map[hex.x][hex.y].node.color = color_at(0)
-    end
     world:append(am.circle(hex_to_pixel(HEX_GRID_CENTER), HEX_SIZE/2, COLORS.MAGENTA, 4))
 
     WORLDSPACE_COORDINATE_OFFSET = -GRID_PIXEL_DIMENSIONS/2

src/hexyz.lua

@@ -426,59 +426,32 @@ end
 -- PATHFINDING
 
 
--- maps each hex of |map| to a numeric value, which is its distance from |start|
--- returns this new map
-function breadth_first_distance(map, start, neighbour_f)
-    local neighbour_f = neighbour_f or function(map, hex) return hex_neighbours(hex) end
-
-    local frontier = { start }
-
-    local distance = {}
-    distance[start.x] = {}
-    distance[start.x][start.y] = 0
+--[[ @TODO bad breadth first
+    local frontier = { _tower.hex }
+    local history = {}
+    history[_tower.hex.x] = {}
+    history[_tower.hex.x][_tower.hex.y] = true
 
     while not (#frontier == 0) do
         local current = table.remove(frontier, 1)
 
-        for _,next_ in pairs(neighbour_f(map, current)) do
-            if not map_get(distance, next_.x, next_.y) then
-                table.insert(frontier, next_)
-                map_set(distance, next_.x, next_.y, 1 + map_get(distance, current.x, current.y))
-            end
+        for _,neighbour in pairs(grid_neighbours(HEX_MAP, _tower.hex)) do
+            if not (history[neighbour.x] and history[neighbour.x][neighbour.y]) then
+                local mob = mob_on_hex(neighbour)
+                if mob then
+                    _tower.target = mob
+                    break
                 end
+                table.insert(frontier, neighbour)
             end
-
-    return setmetatable(distance, { __index = {
-        get = function(x, y) return map_get(distance, x, y) end
-    }})
         end
 
--- maps each hex of |map| to an adjacent cell that is on the path to |start|, or nil if no path exists
--- returns this new map
-function breadth_first_vectorfield(map, start, neighbour_f)
-    local neighbour_f = neighbour_f or function(map, hex) return hex_neighbours(hex) end
-
-    local frontier = { start }
-
-    local came_from = {}
-    came_from[start.x] = {}
-    came_from[start.x][start.y] = false
-
-    while not (#frontier == 0) do
-        local current = table.remove(frontier, 1)
-
-        for _,next_ in pairs(neighbour_f(map, current)) do
-            if not map_get(came_from, next_.x, next_.y) then
-                table.insert(frontier, next_)
-                map_set(came_from, next_.x, next_.y, current)
-            end
-        end
+        if _tower.target then
+            log(_tower.target)
+            break
         end
-
-    came_from.get = function(x, y) return map_get(came_from, x, y) end
-
-    return came_from
     end
+]]
 
 -- generic A* pathfinding
 --
@@ -511,7 +484,7 @@ function Astar(map, start, goal, neighbour_f, heuristic_f, cost_f)
         end
 
         for _,next_ in pairs(neighbour_f(map, current.hex)) do
-            local new_cost = map_get(path_so_far, current.hex.x, current.hex.y) + cost_f(current, next_)
+            local new_cost = map_get(path_so_far, current.hex.x, current.hex.y) + cost_f(current.hex, next_)
             local next_cost = map_get(path_so_far, next_.x, next_.y)
 
             if not next_cost or new_cost < next_cost then

src/main.lua

@@ -6,16 +6,20 @@ math.random()
 math.random()
 
 require "color"
+require "entity"
 require "grid"
 require "mob"
+require "projectile"
 require "tower"
 
 -- Globals
-WIN = am.window{ width = 1920, height = 1080 }
+WIN = am.window{ width = 1920, height = 1080, title = "hexyz" }
+
+OFF_SCREEN = vec2(WIN.width * 2) -- arbitrary pixel position that is garunteed to be off screen
 
 TIME = 0
 SCORE = 0
-OFF_SCREEN = vec2(WIN.width * 2) -- random pixel position that is garunteed to be off screen
+MOUSE = vec2(0)
 
 local COORDINATE_DISPLAY_TYPES = {
     CENTERED_EVENQ = 0,
@@ -27,9 +31,9 @@ local COORDINATE_DISPLAY_TYPE = COORDINATE_DISPLAY_TYPES.CENTERED_EVENQ
 local function game_action(scene)
     TIME                    = am.current_time()
     SCORE                   = TIME
+    MOUSE                   = WIN:mouse_position()
 
-    local mouse = WIN:mouse_position()
-    local hex = pixel_to_hex(mouse - WORLDSPACE_COORDINATE_OFFSET)
+    local hex               = pixel_to_hex(MOUSE - WORLDSPACE_COORDINATE_OFFSET)
     local rounded_mouse     = hex_to_pixel(hex) + WORLDSPACE_COORDINATE_OFFSET
     local evenq             = hex_to_evenq(hex)
     local centered_evenq    = evenq{ y = -evenq.y } - vec2(math.floor(HEX_GRID_WIDTH/2)
@@ -37,19 +41,25 @@ local function game_action(scene)
     local tile = HEX_MAP.get(hex.x, hex.y)
     local hot = is_interactable(tile, evenq{ y = -evenq.y })
 
+    do_mob_spawning()
+    do_entity_updates()
+
     if WIN:mouse_pressed"left" then
         if hot and is_buildable(hex, tile, nil) then
-            make_tower(hex)
+            make_and_register_tower(hex)
         end
     end
 
-    if WIN:key_pressed"f3" then
+    if WIN:key_pressed"escape" then
+        WIN.scene = game_scene()
+
+    elseif WIN:key_pressed"f3" then
         COORDINATE_DISPLAY_TYPE = (COORDINATE_DISPLAY_TYPE + 1) % #table.keys(COORDINATE_DISPLAY_TYPES)
-    end
 
-    do_tower_updates()
-    do_mob_updates()
-    do_mob_spawning()
+    elseif WIN:key_pressed"f4" then
+        log(HEX_MAP.seed)
+        print(HEX_MAP.seed)
+    end
 
     if tile and hot then
         WIN.scene"hex_cursor".center = rounded_mouse
@@ -94,7 +104,8 @@ local function toolbelt()
     return toolbelt
 end
 
-local function game_scene()
+-- @NOTE must be global to allow the game_action to reference it
+function game_scene()
     local score = am.translate(WIN.left + 10, WIN.top - 20) ^ am.text("", "left"):tag"score"
     local coords = am.translate(WIN.right - 10, WIN.top - 20) ^ am.text("", "right"):tag"coords"
     local hex_cursor = am.circle(OFF_SCREEN, HEX_SIZE, COLORS.TRANSPARENT, 6):tag"hex_cursor"
@@ -122,12 +133,8 @@ local function game_scene()
     return scene
 end
 
-local function init()
 require "texture"
 load_textures()
 WIN.scene = am.scale(1) ^ game_scene()
-end
-
-init()
 noglobals()
 

src/mob.lua

@@ -1,54 +1,37 @@
 
 
-local MOBS = {}
---[[
-    mob structure:
-    {
-        TOB         - float     -- time stamp in seconds of when the tower was spawned
-        hex         - vec2      -- hexagon the mob is on
-        position    - vec2      -- true pixel coordinates
-        node        - node      -- the root graph node for this mob
-        update      - function  -- function that gets called every frame with itself as an argument
-        path        - 2d table  -- map of hexes to other hexes, forms a path
-        speed       - number    -- multiplier on distance travelled per frame, up to the update function to use correctly
-    }
-]]
-
 require "extra"
 require "sound"
 
-
-local MOB_UPDATES = {
-    BEEPER = function(mob, index)
-        mob.hex = pixel_to_hex(mob.position)
-
-        local frame_target = mob.path[mob.hex.x] and mob.path[mob.hex.x][mob.hex.y]
-
-        if frame_target then
-            mob.position = mob.position + math.normalize(hex_to_pixel(frame_target.hex) - mob.position) * mob.speed
-            mob.node.position2d = mob.position
-
-        else
-            if mob.hex == HEX_GRID_CENTER then
+function mob_die(mob, entity_index)
     WIN.scene"world":action(
         am.play(am.sfxr_synth(SOUNDS.EXPLOSION1), false, math.random() + 0.5)
     )
+    delete_entity(entity_index)
+end
 
-                table.remove(MOBS, index)
-                WIN.scene"world":remove(mob.node)
-            else
-                log("stuck")
+-- @NOTE returns i,v in the table
+function mob_on_hex(hex)
+    return table.find(ENTITIES, function(entity)
+        return entity.type == ENTITY_TYPE.MOB and entity.hex == hex
+    end)
+end
+
+function do_hit_mob(mob, damage, index)
+    mob.health = mob.health - damage
+
+    if mob.health < 1 then
+        mob_die(mob, index)
     end
 end
 
-        -- passive animation
-        if math.random() < 0.01 then
-            mob.node"rotate":action(am.tween(0.3, { angle = mob.node"rotate".angle + math.pi*3 }))
-        else
-            mob.node"rotate".angle = math.wrapf(mob.node"rotate".angle + am.delta_time, math.pi*2)
+function check_for_broken_mob_pathing(hex)
+    for _,entity in pairs(ENTITIES) do
+        if entity.type == ENTITY_TYPE.MOB and entity.path[hex.x] and entity.path[hex.x][hex.y] then
+            entity.path = get_mob_path(entity, HEX_MAP, entity.hex, HEX_GRID_CENTER)
+        end
     end
 end
-}
 
 -- check if a the tile at |hex| is passable by |mob|
 local function mob_can_pass_through(mob, hex)
@@ -56,8 +39,11 @@ local function mob_can_pass_through(mob, hex)
     return tile and tile.elevation < 0.5 and tile.elevation > -0.5
 end
 
-local function get_mob_path(map, start, goal, mob)
-    return Astar(map, goal, start, -- goal and start are switched intentionally
+-- @TODO performance.
+-- try reducing map size by identifying key nodes (inflection points)
+-- there are performance hits everytime we spawn a mob and it's Astar's fault
+function get_mob_path(mob, map, start, goal)
+    return Astar(map, goal, start,
         -- neighbour function
         function(map, hex)
             return table.filter(grid_neighbours(map, hex), function(_hex)
@@ -70,13 +56,13 @@ local function get_mob_path(map, start, goal, mob)
 
         -- cost function
         function(from, to)
-            return math.abs(map.get(to.x, to.y).elevation)
+            return math.abs(map.get(from.x, from.y).elevation - map.get(to.x, to.y).elevation)
         end
     )
 end
 
 -- @FIXME there's a bug here where the position of the spawn hex is sometimes 1 closer to the center than we want
-local function get_spawn_hex(mob)
+local function get_spawn_hex()
     local spawn_hex
     repeat
         -- ensure we spawn on an random tile along the map's edges
@@ -100,48 +86,61 @@ local function get_spawn_hex(mob)
         spawn_hex = evenq_to_hex(vec2(x, -y))
         local tile = HEX_MAP[spawn_hex.x][spawn_hex.y]
 
-    until mob_can_pass_through(mob, spawn_hex)
+    until is_passable(tile)
 
     return spawn_hex
 end
 
-local function make_mob()
-    local mob = {}
+local function make_and_register_mob()
+    local mob = make_and_register_entity(
+        -- type
+        ENTITY_TYPE.MOB,
 
-    mob.TOB         = TIME
-    mob.update      = MOB_UPDATES.BEEPER
-    mob.hex         = get_spawn_hex(mob)
-    mob.position    = hex_to_pixel(mob.hex)
-    mob.path        = get_mob_path(HEX_MAP, mob.hex, HEX_GRID_CENTER, mob)
-    mob.speed       = 10
+        -- hex spawn position
+        get_spawn_hex(),
 
-    mob.node = am.translate(mob.position)
-               ^ am.scale(2)
-               ^ am.rotate(mob.TOB)
-               ^ pack_texture_into_sprite(TEX_MOB1_1, 20, 20)
+        -- node
+        am.scale(2)
+        ^ am.rotate(TIME)
+        ^ pack_texture_into_sprite(TEX_MOB1_1, 20, 20),
 
-    WIN.scene"world":append(mob.node)
+        -- update
+        function(_mob, _mob_index)
+            _mob.hex = pixel_to_hex(_mob.position)
 
-    return mob
+            local frame_target = _mob.path[_mob.hex.x] and _mob.path[_mob.hex.x][_mob.hex.y]
+
+            if frame_target then
+                _mob.position = _mob.position + math.normalize(hex_to_pixel(frame_target.hex) - _mob.position) * _mob.speed
+                _mob.node.position2d = _mob.position
+
+            else
+                if _mob.hex == HEX_GRID_CENTER then
+                    mob_die(_mob, index)
+                else
+                    log("stuck")
+                end
             end
 
-function mob_on_hex(hex)
-    return table.find(MOBS, function(mob)
-        return mob.hex == hex
-    end)
+            -- passive animation
+            if math.random() < 0.01 then
+                _mob.node"rotate":action(am.tween(0.3, { angle = _mob.node"rotate".angle + math.pi*3 }))
+            else
+                _mob.node"rotate".angle = math.wrapf(_mob.node"rotate".angle + am.delta_time, math.pi*2)
+            end
+        end
+    )
+
+    mob.path        = get_mob_path(mob, HEX_MAP, mob.hex, HEX_GRID_CENTER)
+    mob.health      = 10
+    mob.speed       = 1
 end
 
 local SPAWN_CHANCE = 50
 function do_mob_spawning()
     --if WIN:key_pressed"space" then
     if math.random(SPAWN_CHANCE) == 1 then
-        table.insert(MOBS, make_mob())
-    end
-end
-
-function do_mob_updates()
-    for i,mob in pairs(MOBS) do
-        mob.update(mob, i)
+        make_and_register_mob()
     end
 end
 

src/projectile.lua

@@ -0,0 +1,33 @@
+
+
+
+function make_and_register_projectile(hex, vector, velocity)
+    local projectile = make_and_register_entity(
+        -- type
+        ENTITY_TYPE.PROJECTILE,
+
+        hex,
+
+        -- node
+        am.line(vector, vector * 4, 2, COLORS.CLARET),
+
+        function(_projectile, _projectile_index)
+            _projectile.position        = _projectile.position + vector * velocity
+            _projectile.node.position2d = _projectile.position
+            _projectile.hex             = pixel_to_hex(_projectile.position)
+
+            local mob_index,mob = mob_on_hex(_projectile.hex)
+            if mob and (math.distance(mob.position, _projectile.position) > _projectile.hitbox_radius) then
+                do_hit_mob(mob, _projectile.damage, mob_index)
+                delete_entity(_projectile_index)
+                WIN.scene"world":action(am.play(am.sfxr_synth(SOUNDS.HIT1)))
+            end
+        end
+    )
+
+    projectile.vector = vector
+    projectile.velocity = velocity
+    projectile.damage = 5
+    projectile.hitbox_radius = 10
+end
+

src/scratch

@@ -0,0 +1,5 @@
+
+
+x = y - floor(z/2)
+
+j + floor(z/2) = j2

src/sound.lua

@@ -2,6 +2,8 @@
 SOUNDS = {
     EXPLOSION1      = 49179102, -- this slowed sounds metal as fuck
     EXPLOSION2      = 19725402,
+    EXPLOSION3      = 69338002,
+    HIT1            = 25811004,
     LASER1          = 79859301,
     PUSH1           = 30455908,
     BIRD1           = 50838307,

src/texture.lua

@@ -1,4 +1,5 @@
 
+
 function load_textures()
     TEX_MARQUIS             = am.texture2d("../res/marquis.png")
 
@@ -6,8 +7,10 @@ function load_textures()
 
     TEX_WALL_CLOSED         = am.texture2d("../res/wall_closed.png")
     TEX_TOWER1              = am.texture2d("../res/tower1.png")
+    TEX_TOWER2              = am.texture2d("../res/tower2.png")
 
     TEX_MOB1_1              = am.texture2d("../res/mob1_1.png")
+    TEX_MOB2_1              = am.texture2d("../res/mob2_1.png")
 end
 
 function pack_texture_into_sprite(texture, width, height)

src/tower.lua

@@ -1,43 +1,59 @@
 
-local TOWERS = {}
---[[
-    tower structure:
-    {
-        TOB         - float     -- time stamp in seconds of when the tower was spawned
-        hex         - vec2      -- hexagon the tower is on
-        position    - vec2      -- true pixel coordinates
-        node        - node      -- the root graph node for this tower
-        update      - function  -- function that gets called every frame with itself as an argument
-    }
-]]
 
 function is_buildable(hex, tile, tower)
     local blocked = mob_on_hex(hex)
     return not blocked and is_passable(tile)
 end
 
-function make_tower(hex)
-    local tower = {}
-
-    tower.TOB           = TIME
-    tower.hex           = hex
-    tower.position      = hex_to_pixel(tower.hex)
-    tower.node          = am.translate(tower.position)
-                          ^ pack_texture_into_sprite(TEX_TOWER1, 55, 55)
-
-    tower.update        = function(_tower) end
+function make_and_register_tower(hex)
+    local tower = make_and_register_entity(
+        -- type
+        ENTITY_TYPE.TOWER,
+
+        -- spawning hex
+        hex,
+
+        -- node
+        pack_texture_into_sprite(TEX_TOWER2, 45, 34),
+
+        -- update function
+        function(_tower, _tower_index)
+            if not _tower.target_index then
+                for index,entity in pairs(ENTITIES) do
+                    if entity and entity.type == ENTITY_TYPE.MOB then
+                        local d = math.distance(entity.hex, _tower.hex)
+                        if d <= _tower.range then
+                            _tower.target_index = index
+                            break
+                        end
+                    end
+                end
+            else
+                if ENTITIES[_tower.target_index] == nil then
+                    _tower.target_index = false
 
-    -- make this cell impassable
-    --HEX_MAP.get(hex.x, hex.y).elevation = 2
+                elseif (TIME - _tower.last_shot_time) > 1 then
+                    local entity = ENTITIES[_tower.target_index]
 
-    WIN.scene"world":append(tower.node)
+                    make_and_register_projectile(
+                        _tower.hex,
+                        math.normalize(hex_to_pixel(entity.hex) - _tower.position),
+                        5
+                    )
 
-    return tower
+                    _tower.last_shot_time = TIME
+                    _tower.node:action(am.play(am.sfxr_synth(SOUNDS.EXPLOSION3)))
+                end
             end
-
-function do_tower_updates()
-    for i,tower in pairs(TOWERS) do
-        tower.update(tower, i)
         end
+    )
+
+    tower.range             = 10
+    tower.last_shot_time    = tower.TOB
+    tower.target_index      = false
+
+    -- make this cell impassable
+    HEX_MAP[hex.x][hex.y].elevation = 2
+    check_for_broken_mob_pathing(hex)
 end