Added HUD widgets, make Boot and Close use button_up instead of button_down

lib/hud/widgets/health.rb

@@ -0,0 +1,48 @@
+class IMICFPS
+  class HUD
+    class HealthWidget < HUD::Widget
+      def setup
+        @spacer = 0
+        @text = Text.new("")
+        @width = 512
+        @height = 24
+        @slant = 32
+
+        @color = Gosu::Color.rgba(100, 100, 200, 128)
+        @shield = Gosu::Color.rgba(200, 100, 50, 200)
+
+        @health = 0.0
+      end
+
+      def draw
+        @text.draw
+        fill_quad(
+          window.width / 2 - @width / 2, @spacer, # TOP LEFT
+          window.width / 2 + @width / 2, @spacer, # TOP RIGHT
+          window.width / 2 + @width / 2 - @slant, @spacer + @height, # BOTTOM RIGHT
+          window.width / 2 - @width / 2 + @slant, @spacer + @height, # BOTTOM LEFT
+          @color
+        )
+
+        # Current Health
+        fill_quad(
+          window.width / 2 - @width / 2, @spacer, # TOP LEFT
+          (window.width / 2 - @width / 2) + @width * @health, @spacer, # TOP RIGHT
+          (window.width / 2 - @width / 2) + @width * @health - @slant, @spacer + @height, # BOTTOM RIGHT
+          window.width / 2 - @width / 2 + @slant, @spacer + @height, # BOTTOM LEFT
+          @shield
+        )
+      end
+
+      def update
+        percentage = "#{(@health * 100).round}".rjust(3, "0")
+        @text.text = "[Health #{percentage}%]"
+        @text.x = window.width / 2 - @text.width / 2
+        @text.y = @spacer + @height / 2 - @text.height / 2
+
+        @health += 0.1 * window.dt
+        @health = 0 if @health > 1.0
+      end
+    end
+  end
+end