/lib/chingu/traits/viewport.rb

 1#--
 2#
 3# Chingu -- OpenGL accelerated 2D game framework for Ruby
 4# Copyright (C) 2009 ippa / ippa@rubylicio.us
 5#
 6# This library is free software; you can redistribute it and/or
 7# modify it under the terms of the GNU Lesser General Public
 8# License as published by the Free Software Foundation; either
 9# version 2.1 of the License, or (at your option) any later version.
10#
11# This library is distributed in the hope that it will be useful,
12# but WITHOUT ANY WARRANTY; without even the implied warranty of
13# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14# Lesser General Public License for more details.
15#
16# You should have received a copy of the GNU Lesser General Public
17# License along with this library; if not, write to the Free Software
18# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19#
20#++
21
22module Chingu
23  module Traits
24    #
25    # A chingu trait providing velocity and acceleration logic. 
26    # Adds parameters: velocity_x/y, acceleration_x/y and modifies self.x / self.y
27    # Also keeps previous_x and previous_y which is the x, y before modification.
28    # Can be useful for example collision detection
29    #
30    module Viewport
31      attr_accessor :viewport
32      
33      module ClassMethods
34        def initialize_trait(options = {})
35          trait_options[:viewport] = {:apply => true}.merge(options)
36        end
37      end
38      
39      def setup_trait(options)
40        @viewport_options = {:debug => false}.merge(options)
41        
42        @viewport = Chingu::Viewport.new()
43        @viewport.x = options[:viewport_x] || 0
44        @viewport.y = options[:viewport_y] || 0
45        
46        super
47      end
48      
49      def inside_viewport?(object)
50        puts "Deprecated, use self.viewport.inside?() instead"
51        object.x >= @viewport.x && object.x <= (@viewport.x + $window.width) &&
52        object.y >= @viewport.y && object.y <= (@viewport.y + $window.height)
53      end
54
55      # Returns true object is outside the view port
56      def outside_viewport?(object)
57        puts "Deprecated, use self.viewport.outside?() instead"
58        not inside_viewport?(object)
59      end
60      
61			# Take care of laggy viewport movements
62      def update_trait
63				@viewport.move_towards_target
64				super
65      end
66      
67      #
68      # Override game states default draw that draws objects relative to the viewport.
69      # It only draws game objects inside the viewport. (GOSU does no such optimizations)
70      #
71      def draw
72        #self.game_objects.draw_relative(-@viewport.x, -@viewport.y)
73        @viewport.apply { super }
74      end      
75    end
76  end
77end