Stubbed Map, implemented optimized Map tile rendering, made Camera viewport explicitly defined

lib/map.rb

@@ -0,0 +1,62 @@
+class IMICRTS
+  class Map
+    Tile = Struct.new(:position, :color, :size)
+
+    def initialize(width:, height:, tile_size: 32)
+      @width, @height = width, height
+      @tile_size = tile_size
+
+      @tiles = []
+
+      height.times do |y|
+        width.times do |x|
+          @tiles.push(
+            Tile.new(
+              CyberarmEngine::Vector.new(x * @tile_size, y * @tile_size, ZOrder::TILE),
+              Gosu::Color.rgb(rand(25), rand(150..200), rand(25)),
+              @tile_size
+            )
+          )
+        end
+      end
+    end
+
+    def draw(camera)
+      visible_tiles(camera).each do |tile|
+        Gosu.draw_rect(
+          tile.position.x, tile.position.y,
+          @tile_size, @tile_size,
+          tile.color, tile.position.z
+        )
+      end
+    end
+
+    def visible_tiles(camera)
+      _tiles = []
+
+      top_left = camera.center - CyberarmEngine::Vector.new($window.width / 2, $window.height / 2) / camera.zoom
+      top_left.x = top_left.x.ceil
+      top_left.y = top_left.y.ceil
+
+      top_left /= @tiles.first.size
+
+      # +1 to overdraw a bit to hide pop-in
+      _width  = ($window.width / @tile_size) + 1
+      _height = ($window.height / @tile_size) + 1
+
+      _height.times do |y|
+        _width.times do |x|
+          if tile = tile_at(x + top_left.x, y + top_left.y)
+            _tiles.push(tile)
+          end
+        end
+      end
+
+      return _tiles
+    end
+
+    def tile_at(x, y)
+      @tiles[x + y * @width]
+    end
+  end
+end