contrib/action_nitro/src/game/ai.nit

   1 # This file is part of NIT ( http://www.nitlanguage.org ).
   2 #
   3 # Licensed under the Apache License, Version 2.0 (the "License");
   4 # you may not use this file except in compliance with the License.
   5 # You may obtain a copy of the License at
   6 #
   7 #     http://www.apache.org/licenses/LICENSE-2.0
   8 #
   9 # Unless required by applicable law or agreed to in writing, software
  10 # distributed under the License is distributed on an "AS IS" BASIS,
  11 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 # See the License for the specific language governing permissions and
  13 # limitations under the License.
  14
  15 # Smart enemies
  16 module ai
  17
  18 import core
  19
  20 redef class Enemy
  21
  22         # Square of the range to shoot at the player
  23         fun range2: Float do return 32.0*32.0
  24
  25         redef fun update(dt, world)
  26         do
  27                 super
  28
  29                 var player = world.player
  30                 if is_alive and player != null and player.is_alive and can_shoot(world) then
  31                         # Shoot if possible
  32                         if player.center.dist2(self.center) < range2 then
  33                                 aim_and_shoot(world, player)
  34                         end
  35                 end
  36         end
  37
  38         # Aim to shoot at `target`
  39         fun aim_and_shoot(world: World, target: Body)
  40         do
  41                 # TODO aim forward of `moving` target
  42                 var angle = self.center.atan2(target.center)
  43
  44                 shoot(angle, world)
  45         end
  46
  47         # Go to `target` using jetpack-like movement
  48         fun go_to(target: Point3d[Float], displacement: Float) do
  49                 var sc = center
  50                 var k = 1.0
  51                 if target.x < sc.x then
  52                         inertia.x -= k
  53                         if inertia.x < -displacement then inertia.x = -displacement
  54                 else
  55                         inertia.x += k
  56                         if inertia.x > displacement then inertia.x = displacement
  57                 end
  58                 if target.y < sc.y then
  59                         inertia.y -= k
  60                         if inertia.y < -displacement then inertia.y = -displacement
  61                 else
  62                         inertia.y += k
  63                         if inertia.y > displacement then inertia.y = displacement
  64                 end
  65         end
  66 end
  67
  68 redef class JetpackEnemy
  69         redef fun update(dt, world)
  70         do
  71                 super
  72
  73                 var player = world.player
  74                 if is_alive and player != null and player.is_alive and can_shoot(world) then
  75                         # Move towards player
  76                         var target = player.center
  77                         go_to(target, 40.0)
  78                 end
  79         end
  80 end
  81
  82 redef class Boss
  83         redef fun range2 do return 64.0*64.0
  84 end