Finished allowing placement and collision detection. However, the placement is very inconsistent. Thinking about redoing coordinates again...

gamegrid.rb

@@ -0,0 +1,71 @@
+# Nathan Hinton
+# Holds a grid of each otem in the game
+
+class GameGrid
+  def initialize(game_width, game_height)
+
+    @game_grid = []
+    game_width.times do |xx|
+      @game_grid.append(Array.new(game_height))
+    end
+  end
+
+
+  ## Add an item to the grid
+  # @param x [Integer] The x position (top left corner of item)
+  # @param y [Integer] The y position (top left corner of item)
+  # @param item [Object] The item to add. Should be an actual reference to the item
+  # @retval [Boolean] True if the item was placed, false otherwise (space conflict)
+  def add_item(x, y, item)
+    size_x = item.size_x
+    size_y = item.size_y
+
+    puts "#{item.to_s}"
+    puts "top left: (#{x}, #{y}), size: (#{size_x}, #{size_y})"
+
+    # Check that the grid is empty in those spots:
+    size_x.times do |xx|
+      size_y.times do |yy|
+        unless @game_grid[x + xx][y + yy].nil?
+          puts "Failed to add item: #{item.to_s}:"
+          puts " - top left: (#{x}, #{y}), size: (#{size_x}, #{size_y}), collision: (#{xx}, #{yy})"
+          return false
+        end
+      end
+    end
+
+    # place item in grid
+    size_x.times do |xx|
+      size_y.times do |yy|
+        @game_grid[x + xx][y + yy] = item
+      end
+    end
+    return true
+  end
+
+  ## Add an item to the grid
+  # @param x [Integer] The x position (top left corner of item)
+  # @param y [Integer] The y position (top left corner of item)
+  # @param item [Object] The item to remove. Used to ensure we are removing the right thing.
+  def remove_item(x, y, item)
+    size_x = item.size_x
+    size_y = item.size_y
+
+    # Check that the grid is empty in those spots:
+    size_x.times do |xx|
+      size_y.times do |yy|
+        if @game_grid[x + xx][y + yy] != item
+          raise RuntimeError.new('Item mismatch in internal game grid! Game state corrupted1')
+        end
+      end
+    end
+
+    # place item in grid
+    size_x.times do |xx|
+      size_y.times do |yy|
+        @game_grid[x + xx][y + yy] = nil
+      end
+    end 
+ end
+
+end