Module: Chingu::Traits::CollisionDetection

Defined in:
lib/chingu/traits/collision_detection.rb

Overview

Research: 1) QuadTrees: lab.polygonal.de/2007/09/09/quadtree-demonstration/ 2) Sweep and Prune

SEE: www.shmup-dev.com/forum/index.php?board=65.0

Makes use of 3 attributes

@bounding_box      - a Rect-instance, uses in bounding_box collisions
@radius            -
@detect_collisions - [true|false], should object be checked for collisions with Object.each_collision

Defined Under Namespace

Modules: ClassMethods

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#bounding_box ⇒ Object

Returns the value of attribute bounding_box.



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# File 'lib/chingu/traits/collision_detection.rb', line 38

def bounding_box
  @bounding_box
end

#radius ⇒ Object

Returns the value of attribute radius.



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# File 'lib/chingu/traits/collision_detection.rb', line 38

def radius
  @radius
end

Class Method Details

.included(base) ⇒ Object

attr_accessor :detect_collisions # slowed down example9 with 3 fps



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# File 'lib/chingu/traits/collision_detection.rb', line 41

def self.included(base)
  base.extend(ClassMethods)
end

Instance Method Details

#bounding_box_collision?(object2) ⇒ Boolean

Collide self with a given game object by checking both objects bounding_box’es Returns true if colliding.

Returns:

  • (Boolean) 


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# File 'lib/chingu/traits/collision_detection.rb', line 75

def bounding_box_collision?(object2)
  self.bounding_box.collide_rect?(object2.bounding_box)
end

#collides?(object2) ⇒ Boolean

The standard method called when self needs to be checked for a collision with another object By default it calls bounding_box_collision? which will check for intersectons between the two objects “bounding_box” attributs (a Chingu::Rect instance)

Returns:

  • (Boolean) 


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# File 'lib/chingu/traits/collision_detection.rb', line 66

def collides?(object2)
  bounding_box_collision?(object2)
  #radius_collision?(object2)
end

#each_bounding_box_collision(klasses = []) ⇒ Object

Explicit bounding_box-collision Works like each_collision but with inline-code for speedups



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# File 'lib/chingu/traits/collision_detection.rb', line 128

def each_bounding_box_collision(klasses = [])
  Array(klasses).each do |klass|
    klass.all.each do |object|
      yield(self, object) if @bounding_box.collide_rect?(object.bounding_box)
    end
  end
end

#each_collision(klasses = []) ⇒ Object

Collides self with all objects of given classes Yields self and the objects it collides with



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# File 'lib/chingu/traits/collision_detection.rb', line 103

def each_collision(klasses = [])
  Array(klasses).each do |klass|        
    klass.all.each do |object|
      yield(self, object)   if collides?(object)
    end
  end
end

#each_radius_collision(klasses = []) ⇒ Object

Explicit radius-collision Works like each_collsion but with inline-code for speedups



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# File 'lib/chingu/traits/collision_detection.rb', line 115

def each_radius_collision(klasses = [])
  Array(klasses).each do |klass|
    klass.all.each do |object|
      yield(self, object) if distance(@x, @y, object.x, object.y) < @radius + object.radius
    end
  end
end

#radius_collision?(object2) ⇒ Boolean

Collide self using distance between 2 objects and their radius. Returns true if colliding.

Returns:

  • (Boolean) 


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# File 'lib/chingu/traits/collision_detection.rb', line 83

def radius_collision?(object2)
  distance(self.x, self.y, object2.x, object2.y) < self.radius + object2.radius
end

#setup_trait(options) ⇒ Object

Automaticly try to set a bounding_box and radius. Don’t overwrite if they already exists.



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# File 'lib/chingu/traits/collision_detection.rb', line 48

def setup_trait(options)
  if @x and @y and @image
    @bounding_box ||= Rect.new(@x, @y, @image.width, @image.height)
  end
  
  if @image
    @radius ||= (@image.height + @image.width) / 2 * 0.80
  end
  
  ## @detect_collisions = true
  super
end

#update_trait ⇒ Object

Have bounding box follow game objects x/y



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# File 'lib/chingu/traits/collision_detection.rb', line 90

def update_trait
  if defined?(@bounding_box) && @bounding_box.is_a?(Rect)
    @bounding_box.x = self.x
    @bounding_box.y = self.y
  end
  
  super
end