Module: Rubygame::Sprites::DepthSortGroup

Defined in:

lib/rubygame/sprite.rb

Overview

DepthSortGroup is a mix-in module that extends Group to sort its sprites by their @depth attribute, so that sprites with low depths will appear on top of sprites with higher depths. A sprite’s depth can be any Numeric, or nil (which will be counted as 0).

If two sprites have exactly the same depth, there is no guarantee about which one will be drawn on top of the other. (But, whichever one is on top will stay on top, at least until the group is re-sorted.)

If a sprite’s depth changes after it has been added to the group, you must use the #sort_sprites method for the change to have any effect.

Instance Method Summary

• #<<(sprite) ⇒ Object

  Add a single sprite to the group.

• #push(*sprites) ⇒ Object

  Add multiple sprites to the group, then re-sort all sprites.

• #sort_sprites ⇒ Object

  Sort sprites by depth, in descending order, so that sprites with low depths will be drawn on top of sprites with high depths.

Instance Method Details

#<<(sprite) ⇒ Object

Add a single sprite to the group. For efficiency reasons, this method doesn’t re-sort sprites afterwards. You should use #sort_sprites after you’re done adding sprites. Or, better yet, just use #push.

# File 'lib/rubygame/sprite.rb', line 488

def <<(sprite)
	super
end

#push(*sprites) ⇒ Object

Add multiple sprites to the group, then re-sort all sprites.

# File 'lib/rubygame/sprite.rb', line 493

def push(*sprites)
	sprites.each { |sprite|
		self << sprite
	}
	sort_sprites()
	return self
end

#sort_sprites ⇒ Object

Sort sprites by depth, in descending order, so that sprites with low depths will be drawn on top of sprites with high depths.

If a sprite has a depth of nil, it is sorted as if its depth were 0 (zero).

# File 'lib/rubygame/sprite.rb', line 505

def sort_sprites
	self.sort! { |a,b| (b.depth or 0) <=> (a.depth or 0) }
end