diff --git a/build.bat b/build.bat
index f9c8aed..3a54032 100644
--- a/build.bat
+++ b/build.bat
@@ -2,7 +2,7 @@
 
 pushd %~dp0
 rem cl main.cpp -I.. user32.lib
-rem clang core_main.cpp -O0 -Wall -Wno-unused-function -fno-exceptions -fdiagnostics-absolute-paths -g -o main.exe -Wl,user32.lib
+clang core_main.cpp -O0 -Wall -Wno-unused-function -fno-exceptions -fdiagnostics-absolute-paths -g -o main.exe -Wl,user32.lib
 rem ubuntu run clang core_main.cpp -O0 -Wall -Wno-unused-function -fno-exceptions -fdiagnostics-absolute-paths -g -o core.out
 
 main examples/arms_race/arms_race.core
diff --git a/core_typechecking.cpp b/core_typechecking.cpp
index bc5796f..b091490 100644
--- a/core_typechecking.cpp
+++ b/core_typechecking.cpp
@@ -1263,7 +1263,13 @@ resolve_expr(Ast_Expr *ast, Resolve_Flag flags, Ast_Type *compound_and_const_str
           if(is_pointer(type)) type = type->base;
           type_complete(type);
 
+          if(!type->ast){
+            compiler_error(node->pos, "Builtin type %Q doesn't have anything to access using '.' operator", typestring(type));
+          }
           scope = ((Ast_Decl *)type->ast)->scope;
+          if(!scope){
+            compiler_error(node->pos, "Internal compiler error? Type %Q doesn't have scope, you cannot use '.' on this variable", typestring(type));
+          }
         }
 
         Operand right = resolve_expr(node->right, AST_CANT_BE_NULL, 0, scope);
diff --git a/modules/Math.core b/modules/Math.core
index 85a07ee..45704ce 100644
--- a/modules/Math.core
+++ b/modules/Math.core
@@ -1,8 +1,11 @@
-
 sqrtf :: #foreign (value: F32): F32
 cosf  :: #foreign (value: F32): F32
 sinf  :: #foreign (value: F32): F32
 
+floorf :: #foreign (value: F32): F32
+roundf :: #foreign (value: F32): F32
+ceilf  :: #foreign (value: F32): F32
+
 Vec2I  :: struct;; x: S64; y: S64
 Vec2   :: struct;; x: F32; y: F32
 
@@ -19,6 +22,22 @@ Vec2   :: struct;; x: F32; y: F32
 "/"    :: (a: Vec2, b: F32) : Vec2 ;; return {a.x/b, a.y/b}
 "/"    :: (a: F32, b: Vec2) : Vec2 ;; return {a/b.x, a/b.y}
 
+"*"    :: (a: Vec2I, b: Vec2I): Vec2I ;; return {a.x*b.x, a.y*b.y}
+"*"    :: (a: Vec2I, b: S64) : Vec2I ;; return {a.x*b, a.y*b}
+"*"    :: (a: S64, b: Vec2I) : Vec2I ;; return {a*b.x, a*b.y}
+"-"    :: (a: Vec2I, b: Vec2I): Vec2I ;; return {a.x-b.x, a.y-b.y}
+"-"    :: (a: Vec2I, b: S64) : Vec2I ;; return {a.x-b, a.y-b}
+"-"    :: (a: S64, b: Vec2I) : Vec2I ;; return {a-b.x, a-b.y}
+"+"    :: (a: Vec2I, b: Vec2I): Vec2I ;; return {a.x+b.x, a.y+b.y}
+"+"    :: (a: Vec2I, b: S64) : Vec2I ;; return {a.x+b, a.y+b}
+"+"    :: (a: S64, b: Vec2I) : Vec2I ;; return {a+b.x, a+b.y}
+"/"    :: (a: Vec2I, b: Vec2I): Vec2I ;; return {a.x/b.x, a.y/b.y}
+"/"    :: (a: Vec2I, b: S64) : Vec2I ;; return {a.x/b, a.y/b}
+"/"    :: (a: S64, b: Vec2I) : Vec2I ;; return {a/b.x, a/b.y}
+
+FloorVec2ToVec2I :: (a: Vec2): Vec2I ;; return {floorf(a.x)->S64, floorf(a.y)->S64}
+CastVec2ToVec2I :: (a: Vec2): Vec2I ;; return {a.x->S64, a.y->S64}
+
 F32_Clamp :: (min: F32, value: F32, max: F32): F32
   if value > max;; return max
   if value < min;; return min
@@ -31,3 +50,8 @@ F32_ClampBottom :: (min: F32, value: F32): F32
 F32_Absolute :: (val: F32): F32
   if val < 0;; return -val
   return val
+
+F32_Min :: (a: F32, b: F32): F32
+  if a > b ;; return b ; return a
+F32_Max :: (a: F32, b: F32): F32
+  if a > b ;; return a ; return b
diff --git a/modules/Multimedia.core b/modules/Multimedia.core
index d8c3daa..c06e72c 100644
--- a/modules/Multimedia.core
+++ b/modules/Multimedia.core
@@ -29,6 +29,8 @@ MUWindow :: struct
   x: S64
   y: S64
   sizef: Vec2
+  size: Vec2I
+  resizable: Bool
 
 MUTime :: struct
   total      : F64
diff --git a/modules/win32_multimedia.core b/modules/win32_multimedia.core
index 903e395..3fcc1a4 100644
--- a/modules/win32_multimedia.core
+++ b/modules/win32_multimedia.core
@@ -93,7 +93,12 @@ SetWindowPosition :: (window: HWND, style: DWORD, pos: Vec2I): void
   AdjustWindowRect(window, style, &rect)
   SetWindowPos(window, 0, rect.left, rect.top, 0, 0, SWP_NOACTIVATE | SWP_NOZORDER | SWP_NOSIZE)
 
-StartMultimedia :: (x: S64 = 1280, y: S64 = 720, title: String = "Hello people!", target_ms: F64 = 0.0166666)
+StartMultimedia :: (
+  x: S64 = 1280, y: S64 = 720,
+  title: String = "Hello people!",
+  window_resizable: Bool = false,
+  target_ms: F64 = 0.0166666
+)
   Mu.time.delta = target_ms
   if timeBeginPeriod(1) == TIMERR_NOERROR
     Mu.os.good_scheduling = true
@@ -113,7 +118,7 @@ StartMultimedia :: (x: S64 = 1280, y: S64 = 720, title: String = "Hello people!"
   }
   Assert(RegisterClassW(&w) != 0)
 
-  style: DWORD = GetWindowStyle(false)
+  style: DWORD = GetWindowStyle(window_resizable)
   Mu.os.window = CreateWindowExW(
     dwExStyle = 0, hWndParent = 0, hMenu = 0, lpParam = 0,
     X = CW_USEDEFAULT, Y = CW_USEDEFAULT, nWidth = x->int, nHeight = y->int,
@@ -132,9 +137,11 @@ StartMultimedia :: (x: S64 = 1280, y: S64 = 720, title: String = "Hello people!"
   Mu.os.window_dc = GetDC(Mu.os.window)
   Mu.os.bitmap    = CreateBitmap(Mu.os.window_dc, size)
 
+  Mu.window.resizable = window_resizable
   Mu.screen = Mu.os.bitmap.data
   Mu.window.x = size.x
   Mu.window.y = size.y
+  Mu.window.size = size
   Mu.window.sizef.x = Mu.window.x->F32
   Mu.window.sizef.y = Mu.window.y->F32
 
@@ -149,7 +156,7 @@ UpdateMultimedia :: (): Bool
   size := GetWindowSize(Mu.os.window)
   if size.x != Mu.window.x || size.y != Mu.window.y
     DestroyBitmap(&Mu.os.bitmap)
-    CreateBitmap(Mu.os.window_dc, size)
+    Mu.os.bitmap = CreateBitmap(Mu.os.window_dc, size)
 
   Mu.screen = Mu.os.bitmap.data
   Mu.window.x = size.x