add platform vector and platform quadtree to game type

fcore/platform.sml

@@ -0,0 +1,94 @@
+structure Platform =
+struct
+  (* collision height of a platform.
+   * Visual height may (and probably will) be different. *)
+  val platHeight = 3
+  val rPlatHeight = 3.0
+
+  fun helpGenerateTree (pos, platVec, acc) =
+    if pos = Vector.length platVec then
+      acc
+    else
+      let
+        val {id, x, y, width} = Vector.sub (platVec, pos)
+        val acc = QuadTree.insert
+          (x, y, width, platHeight, 0, 0, 1920, 1080, id, acc)
+      in
+        helpGenerateTree (pos + 1, platVec, acc)
+      end
+
+  fun generateTree platVec = helpGenerateTree (0, platVec, QuadTree.empty)
+
+  fun helpGetDrawVecWider
+    (pos, platVec, acc, winWidth, winHeight, ratio, yOffset) =
+    if pos = Vector.length platVec then
+      Vector.concat acc
+    else
+      let
+        val plat = Vector.sub (platVec, pos)
+        val {x, y, width, id = _} = plat
+
+        val x = Real32.fromInt x * ratio
+        val y = Real32.fromInt y * ratio + yOffset
+
+        val width = Real32.fromInt width * ratio
+        val height = rPlatHeight * ratio
+
+        val block = Block.lerp
+          (x, y, width, height, winWidth, winHeight, 0.0, 0.0, 0.0)
+        val acc = block :: acc
+      in
+        helpGetDrawVecWider
+          (pos + 1, platVec, acc, winWidth, winHeight, ratio, yOffset)
+      end
+
+  fun helpGetDrawVecTaller
+    (pos, platVec, acc, winWidth, winHeight, ratio, xOffset) =
+    if pos = Vector.length platVec then
+      Vector.concat acc
+    else
+      let
+        val plat = Vector.sub (platVec, pos)
+        val {x, y, width, id = _} = plat
+
+        val x = Real32.fromInt x * ratio + xOffset
+        val y = Real32.fromInt y * ratio
+
+        val width = Real32.fromInt width * ratio
+        val height = rPlatHeight * ratio
+
+        val block = Block.lerp
+          (x, y, width, height, winWidth, winHeight, 0.0, 0.0, 0.0)
+        val acc = block :: acc
+      in
+        helpGetDrawVecTaller
+          (pos + 1, platVec, acc, winWidth, winHeight, ratio, xOffset)
+      end
+
+  fun getDrawVec (platVec, width, height) =
+    let
+      val wratio = width / 1920.0
+      val hratio = height / 1080.0
+    in
+      if wratio < hratio then
+        let
+          val scale = 1080.0 * wratio
+          val yOffset =
+            if height > scale then (height - scale) / 2.0
+            else if height < scale then (scale - height) / 2.0
+            else 0.0
+        in
+          helpGetDrawVecWider (0, platVec, [], width, height, wratio, yOffset)
+        end
+      else
+        let
+          val scale = 1920.0 * hratio
+          val xOffset =
+            if width > scale then (width - scale) / 2.0
+            else if width < scale then (scale - width) / 2.0
+            else 0.0
+        in
+          helpGetDrawVecTaller (0, platVec, [], width, height, hratio, xOffset)
+        end
+    end
+end