Implemented Zoom

lib/camera.rb

@@ -1,12 +1,17 @@
 class IMICRTS
   class Camera
-    attr_reader :position, :velocity, :drag
+    attr_reader :position, :velocity, :zoom, :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
+      @zoom = 1.0
+      @min_zoom = 0.25
+      @max_zoom = 4.0
+
+      @drag = 0.8 # Used to arrest velocity
+      @grab_drag = 0.5 # Used when camera is panned using middle mouse button
     end
 
     def window; $window; end
@@ -14,7 +19,10 @@ class IMICRTS
     def draw(&block)
       if block
         Gosu.translate(@position.x, @position.y) do
-          block.call
+          center_point = center
+          Gosu.scale(@zoom, @zoom, center.x, center.y) do
+            block.call
+          end
         end
       end
     end
@@ -26,8 +34,18 @@ class IMICRTS
       @position += @velocity * @scroll_speed
     end
 
+    def mouse_pick(x, y)
+      mouse = CyberarmEngine::Vector.new(x, y)
+
+      normalized = (mouse / @zoom - @position / @zoom) * @zoom
+      normalized.x = normalized.x.floor
+      normalized.y = normalized.y.floor
+
+      return normalized
+    end
+
     def center
-      CyberarmEngine::Vector.new(window.width / 2, window.height / 2) - @position
+      (CyberarmEngine::Vector.new(window.width / 2, window.height / 2) / @zoom - @position / @zoom) * @zoom
     end
 
     def center_around(vector, factor)
@@ -48,7 +66,7 @@ class IMICRTS
 
       if @drag_start
         @velocity *= 0.0
-        @position = CyberarmEngine::Vector.new(window.mouse_x, window.mouse_y) - @drag_start
+        @position = lerp(@position, CyberarmEngine::Vector.new(window.mouse_x, window.mouse_y) - @drag_start, @grab_drag)
       end
     end
 
@@ -57,9 +75,13 @@ class IMICRTS
       when Gosu::KB_H
         @position.x, @position.y = 0.0, 0.0
         @velocity *= 0.0
+      when Gosu::MS_WHEEL_UP
+        @zoom = (@zoom + 0.25).clamp(@min_zoom, @max_zoom)
+      when Gosu::MS_WHEEL_DOWN
+        @zoom = (@zoom - 0.25).clamp(@min_zoom, @max_zoom)
       when Gosu::MS_MIDDLE
         @position_start = @position.clone
-        @drag_start = CyberarmEngine::Vector.new(window.mouse_x, window.mouse_y) - @position
+        @drag_start = CyberarmEngine::Vector.new(window.mouse_x, window.mouse_y)
       end
     end