Refactor character and enemy AI movement logic; implement delta time for smoother updates and replace object (a reserved keyword) with prop.

game/props/base.rb

@@ -0,0 +1,74 @@
+class Prop
+  SIZE = [25, 15]
+
+  # The base class for all props in the game. Props are things that can be interacted with, but do not move (unlike characters).
+  # They cannot be walked through, but can be interacted with (e.g. a chest can be opened, a torch can be lit, a radar can be used).
+  # They are placed at the center of a tile, and their position is represented by the tile coordinate
+  # A prop is one that is placed at the center of a tile (radar, torch & chest)
+  attr_reader :x, :y
+
+  def initialize(x, y)
+    @x = x
+    @y = y
+    @frames_count = 0
+    @spritesheet = nil
+  end
+
+  def collides?(rect)
+    return true if intersects?(self.rect, rect)
+    false
+  end
+
+  def rect
+    [@x * 120 + 90 - SIZE[0] / 2, @y * 120 + 90 - SIZE[1], *SIZE]
+  end
+
+  def update
+    # For now, placeables don't have any behavior
+  end
+
+  def draw
+    return unless @spritesheet
+
+    cam_x, cam_y = $bus.get(:camera_pos) || [0, 0]
+    screen_x = @x * 120 + 90 - cam_x
+    screen_y = @y * 120 + 90 - cam_y
+
+    elapsed = Gosu.milliseconds / 1000.0
+    frame_index = ((elapsed * @frames_count).floor) % @frames_count
+
+    @spritesheet[frame_index].draw(screen_x - 20, screen_y - 20, screen_y, 2, 2)
+
+    return unless DEBUG
+
+    # collision box centered on same point
+    Gosu.draw_rect(screen_x - SIZE[0] / 2, screen_y - SIZE[1], *SIZE, Gosu::Color.new(0x88ff0000), Float::INFINITY)
+  end
+end
+
+class Radar < Prop
+  def initialize(x, y)
+    super(x, y)
+    @frames_count = 4
+    @spritesheet = Gosu::Image.load_tiles("assets/images/radar.png", 20, 20, retro: true)
+  end
+end
+
+class Torch < Prop
+  def initialize(x, y)
+    super(x, y)
+    @frames_count = 4
+    @spritesheet = Gosu::Image.load_tiles("assets/images/torch.png", 20, 20, retro: true)
+  end
+end
+
+class Chest < Prop
+  def initialize(x, y)
+    super(x, y)
+    @wood = rand(0..64)
+    @metal = rand(0..16)
+    @science = rand(0..4)
+    @frames_count = 1
+    @spritesheet = Gosu::Image.load_tiles("assets/images/chest.png", 20, 20, retro: true)
+  end
+end