Moved camera into in own file

i-mic-rts.rb

@@ -5,6 +5,7 @@ rescue LoadError
 end
 
 require_relative "lib/window"
+require_relative "lib/camera"
 
 require_relative "lib/states/boot"
 require_relative "lib/states/game"

lib/camera.rb

@@ -0,0 +1,74 @@
+class IMICRTS
+  class Camera
+    attr_reader :position, :velocity, :drag
+    def initialize(scroll_speed: 10, position: CyberarmEngine::Vector.new(0.0, 0.0))
+      @scroll_speed = scroll_speed
+      @position = position
+      @velocity = CyberarmEngine::Vector.new(0.0, 0.0)
+
+      @drag = 0.8
+    end
+
+    def window; $window; end
+
+    def draw(&block)
+      if block
+        Gosu.translate(@position.x, @position.y) do
+          block.call
+        end
+      end
+    end
+
+    def update
+      move
+      @velocity *= @drag
+
+      @position += @velocity * @scroll_speed
+    end
+
+    def center
+      CyberarmEngine::Vector.new(window.width / 2, window.height / 2) - @position
+    end
+
+    def center_around(vector, factor)
+      @velocity *= 0
+      delta = lerp(self.center, vector, factor)
+      @position += delta * window.dt
+    end
+
+    def lerp(vec1, vec2, factor)
+      (vec1 - vec2) * factor.clamp(0.0, 1.0)
+    end
+
+    def move
+      @velocity.x += @scroll_speed * window.dt if Gosu.button_down?(Gosu::KB_LEFT)  || window.mouse_x < 15
+      @velocity.x -= @scroll_speed * window.dt if Gosu.button_down?(Gosu::KB_RIGHT) || window.mouse_x > window.width - 15
+      @velocity.y += @scroll_speed * window.dt if Gosu.button_down?(Gosu::KB_UP)    || window.mouse_y < 15
+      @velocity.y -= @scroll_speed * window.dt if Gosu.button_down?(Gosu::KB_DOWN)  || window.mouse_y > window.height - 15
+
+      if @drag_start
+        @velocity *= 0.0
+        @position = CyberarmEngine::Vector.new(window.mouse_x, window.mouse_y) - @drag_start
+      end
+    end
+
+    def button_down(id)
+      case id
+      when Gosu::KB_H
+        @position.x, @position.y = 0.0, 0.0
+        @velocity *= 0.0
+      when Gosu::MS_MIDDLE
+        @position_start = @position.clone
+        @drag_start = CyberarmEngine::Vector.new(window.mouse_x, window.mouse_y) - @position
+      end
+    end
+
+    def button_up(id)
+      case id
+      when Gosu::MS_MIDDLE
+        @position_start = nil
+        @drag_start = nil
+      end
+    end
+  end
+end

lib/states/game.rb

@@ -2,8 +2,10 @@ class IMICRTS
   class Game < CyberarmEngine::GuiState
     def setup
       @units = []
+      @camera = Camera.new
+      @mouse_pos = CyberarmEngine::Text.new("X: 0\nY: 0", x: 500, y: 10, z: Float::INFINITY)
 
-      stack(height: 1.0) do
+      @sidebar = stack(height: 1.0) do
         background [0xff555555, Gosu::Color::GRAY]
 
         label "SIDEBAR", text_size: 78
@@ -24,7 +26,6 @@ class IMICRTS
         )
         end
 
-        label ""
 
         button("Leave", width: 1.0) do
           finalize
@@ -35,9 +36,52 @@ class IMICRTS
 
     def draw
       super
+
       Gosu.draw_rect(0, 0, window.width, window.height, Gosu::Color.rgb(10, 175, 35))
 
-      @units.each(&:draw)
+      @camera.draw do
+        @units.each(&:draw)
+
+        draw_rect(@anchor.x - 10, @anchor.y - 10, 20, 20, Gosu::Color::RED, Float::INFINITY) if @anchor
+        # draw_rect(@camera.center.x - 10, @camera.center.y - 10, 20, 20, Gosu::Color::BLACK, Float::INFINITY)
+
+        # mouse_center = CyberarmEngine::Vector.new(window.mouse_x, window.mouse_y) - @camera.position
+        # draw_rect(mouse_center.x - 10, mouse_center.y - 10, 20, 20, Gosu::Color::YELLOW, Float::INFINITY)
+      end
+
+      @mouse_pos.draw
+    end
+
+    def update
+      super
+
+      @camera.update
+
+      if @anchor
+        @camera.center_around(@anchor, 0.9)
+      end
+
+      @mouse_pos.text = "X: #{window.mouse_x}\nY: #{window.mouse_y}"
+    end
+
+    def button_down(id)
+      super
+
+      case id
+      when Gosu::MS_LEFT
+        unless @sidebar.hit?(window.mouse_x, window.mouse_y)
+          @anchor = CyberarmEngine::Vector.new(window.mouse_x, window.mouse_y) - @camera.position
+        end
+      when Gosu::MS_RIGHT
+        @anchor = nil
+      end
+      @camera.button_down(id)
+    end
+
+    def button_up(id)
+      super
+
+      @camera.button_up(id)
     end
 
     def finalize

lib/window.rb

@@ -1,11 +1,25 @@
 class IMICRTS
   class Window < CyberarmEngine::Engine
     def setup
-      Gosu.milliseconds # Start counter
+      @last_update_time = Gosu.milliseconds
 
       self.caption = "I-MIC RTS (#{Gosu.language})"
-      push_state(Boot)
-      # push_state(MainMenu)
+      # push_state(Boot)
+      push_state(MainMenu)
+    end
+
+    def update
+      super
+
+      @last_update_time = Gosu.milliseconds
+    end
+
+    def delta_time
+      Gosu.milliseconds - @last_update_time
+    end
+
+    def dt
+      delta_time / 1000.0
     end
   end
 end