Class: Entity::Block

Inherits:
OwnedEntity show all
Defined in:
lib/game_2d/entity/block.rb

Constant Summary collapse

MAX_LEVEL = 
5
HP_PER_LEVEL = 
5
MAX_HP = 
MAX_LEVEL * HP_PER_LEVEL

Constants included from EntityConstants

EntityConstants::CELL_WIDTH_IN_PIXELS, EntityConstants::MAX_VELOCITY, EntityConstants::PIXEL_WIDTH, EntityConstants::WIDTH

Instance Attribute Summary collapse

Attributes inherited from OwnedEntity

#owner_id

Attributes inherited from Entity

#a, #moving, #space, #x, #x_vel, #y, #y_vel

Instance Method Summary collapse

Methods inherited from OwnedEntity

#owner, #owner=

Methods inherited from Entity

#above, #accelerate, #angle_to_vector, #beneath, #bottom_cell_y, #cx, #cy, #direction, #direction_to, #doomed?, #draw, #draw_angle, #draw_animation, #draw_image, #draw_zorder, #drop_diagonal, #empty_above?, #empty_on_left?, #empty_on_right?, #empty_underneath?, #entities_obstructing, #going_past_entity, #grab!, #grabbed?, #i_hit, #initialize, #left_cell_x, #move, #move_x, #move_y, #moving?, #next_to, #occupied_cells, #on_left, #on_right, #opaque, #pixel_x, #pixel_y, #release!, #right_cell_x, #sleep_now?, #slide_around, #slow_by, #slower_speed, #teleportable?, #top_cell_y, #underfoot, #vector_to_angle, #wake!, #warp

Methods included from ClassMethods

#bottom_cell_y_at, #constrain_velocity, #left_cell_x_at, #right_cell_x_at, #top_cell_y_at

Methods included from Transparency

#transparent?

Methods included from Registerable

#nullsafe_registry_id, #registry_id, #registry_id=, #registry_id?, #registry_id_safe

Methods included from Serializable

#<=>, #==, as_json, #eql?, from_json, #hash, #to_json

Constructor Details

This class inherits a constructor from Entity

Instance Attribute Details

#hp ⇒ Object

Returns the value of attribute hp.



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# File 'lib/game_2d/entity/block.rb', line 10

def hp
  @hp
end

Instance Method Details

#all_state ⇒ Object 



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# File 'lib/game_2d/entity/block.rb', line 14

def all_state; super.push(hp); end

#as_json ⇒ Object 



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# File 'lib/game_2d/entity/block.rb', line 15

def as_json; super.merge!(:hp => hp); end

#destroy! ⇒ Object 



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# File 'lib/game_2d/entity/block.rb', line 123

def destroy!
  owner.disown_block if owner
end

#harmed_by(other, damage = 1) ⇒ Object 



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# File 'lib/game_2d/entity/block.rb', line 118

def harmed_by(other, damage=1)
  self.hp -= damage
  @space.doom(self) if hp <= 0
end

#image_filename ⇒ Object 



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# File 'lib/game_2d/entity/block.rb', line 133

def image_filename; "#{level_name}.gif"; end

#level ⇒ Object 



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# File 'lib/game_2d/entity/block.rb', line 127

def level; (hp - 1) / HP_PER_LEVEL; end

#level_name ⇒ Object 



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# File 'lib/game_2d/entity/block.rb', line 129

def level_name
  %w(dirt brick cement steel unlikelium)[level]
end

#look_ahead_for_support ⇒ Object

Find the highest (if dropping) or lowest (if rising) height that meets the requirements for support



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# File 'lib/game_2d/entity/block.rb', line 88

def look_ahead_for_support
  support_heights = yield *possible_sources_of_support

  (y_vel > 0) ? support_heights.min : support_heights.max
end

#look_ahead_for_support_both_sides ⇒ Object

Need a source of support at the exact same height on both sides



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# File 'lib/game_2d/entity/block.rb', line 72

def look_ahead_for_support_both_sides
  look_ahead_for_support do |left, right|
    left & right
  end
end

#look_ahead_for_support_either_side ⇒ Object

Any source of support will do, either side or both



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# File 'lib/game_2d/entity/block.rb', line 80

def look_ahead_for_support_either_side
  look_ahead_for_support do |left, right|
    left + right
  end
end

#possible_sources_of_support ⇒ Object

Sources of support must intersect with the points next to us, and be:

  • Level with our lower edge, if dropping

  • A point above our upper edge, if rising

  • Close enough that our current velocity will

take us past that point during this tick

This just returns the heights at which we might find support



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# File 'lib/game_2d/entity/block.rb', line 102

def possible_sources_of_support
  target_height = if y_vel > 0 # dropping
    y + HEIGHT - 1
  else # rising
    y - 1
  end

  left_support = opaque(space.entities_at_point(x - 1, target_height)).collect(&:y)
  right_support = opaque(space.entities_at_point(x + WIDTH, target_height)).collect(&:y)

  # Filter out heights we aren't going to reach this tick with
  # our current velocity
  not_too_far = lambda {|its_y| (its_y - y).abs <= y_vel.abs }
  [left_support.find_all(&not_too_far), right_support.find_all(&not_too_far)]
end

#should_fall? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/game_2d/entity/block.rb', line 22

def should_fall?
  return false if owner || !empty_underneath?

  case level
    when 0
      true
    when 1
      !(supported_on_left && supported_on_right)
    when 2
      !(supported_on_left || supported_on_right)
    when 3
      empty_on_left? && empty_on_right? && empty_above?
    when 4
      false
  end
end

#supported_on_left ⇒ Object 



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# File 'lib/game_2d/entity/block.rb', line 39

def supported_on_left
  opaque(space.entities_exactly_at_point(x - WIDTH, y)).any?
end

#supported_on_right ⇒ Object 



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# File 'lib/game_2d/entity/block.rb', line 43

def supported_on_right
  right_support = opaque(space.entities_exactly_at_point(x + WIDTH, y)).any?
end

#to_s ⇒ Object 



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# File 'lib/game_2d/entity/block.rb', line 135

def to_s; "#{super} (#{@hp} HP)"; end

#update ⇒ Object 



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# File 'lib/game_2d/entity/block.rb', line 47

def update
  if should_fall?
    # applies acceleration, but that's all
    space.fall(self)
  else
    self.x_vel = self.y_vel = 0
  end
  # Reduce velocity if necessary, to exactly line up with
  # an upcoming source of support (so we don't move past it)
  if x_vel == 0 && y_vel != 0
    case level
      when 1
        new_y = look_ahead_for_support_both_sides
        self.y_vel = new_y - y if new_y
      when 2
        new_y = look_ahead_for_support_either_side
        self.y_vel = new_y - y if new_y
    end
  end

  move
end

#update_from_json(json) ⇒ Object 



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# File 'lib/game_2d/entity/block.rb', line 17

def update_from_json(json)
  self.hp = json[:hp] if json[:hp]
  super
end