diff --git a/lib/collider.nim b/lib/collider.nim
index 031c641..72c7af6 100644
--- a/lib/collider.nim
+++ b/lib/collider.nim
@@ -61,6 +61,12 @@ proc newBoxCollider*(x, y, w, h: int): PBoxCollider =
   new(result)
   init(result, int16(x), int16(y), UInt16(w), UInt16(h))
 
+
+proc newBoxCollider*(pos: TPoint, w, h: int): PBoxCollider =
+  new(result)
+  init(result, pos.x, pos.y, UInt16(w), UInt16(h))
+
+
 # CircleCollider
 
 proc init*(obj: PCircleCollider, x, y: int16, r: UInt16) =
@@ -76,6 +82,11 @@ proc newCircleCollider*(x, y, r: int): PCircleCollider =
   new(result)
   init(result, int16(x), int16(y), UInt16(r))
 
+proc newCircleCollider*(pos: TPoint, r: int): PCircleCollider =
+  new(result)
+  init(result, pos.x, pos.y, UInt16(r))
+
+
 # MaskCollider
 
 proc init*(obj: PMaskCollider, mask: PMask, x, y: int16) =
@@ -87,6 +98,10 @@ proc newMaskCollider*(mask: PMask, x, y: int): PMaskCollider =
   new(result)
   init(result, mask, int16(x), int16(y))
 
+proc newMaskCollider*(mask: PMask, pos: TPoint): PMaskCollider =
+  new(result)
+  init(result, mask, pos.x, pos.y)
+
 
 # methods
 
diff --git a/lib/common.nim b/lib/common.nim
index 3ef7929..a4874b4 100644
--- a/lib/common.nim
+++ b/lib/common.nim
@@ -15,6 +15,46 @@ const UE_UPDATE_FPS*: cint = 2
 proc distance*(a: TPoint, b: TPoint): float32 =
   return sqrt(pow(toFloat(b.x) - toFloat(a.x), 2.0) + pow(toFloat(b.y) - toFloat(a.y), 2.0))
 
+proc distance*(ax, ay: int16, b: TPoint): float32 {.inline.} =
+  return distance((ax, ay), b)
+
+proc distance*(a: TPoint, bx, by: int16): float32 {.inline.} =
+  return distance(a, (bx, by))
+
+proc distance*(ax, ay: int, b: TPoint): float32 {.inline.} =
+  return distance((ax.int16, ay.int16), b)
+
+proc distance*(a: TPoint, bx, by: int): float32 {.inline.} =
+  return distance(a, (bx.int16, by.int16))
+
+
+# angle direction from one to other point
+proc direction*(a: TPoint, b: TPoint): float64 =
+  let dx = float(a.x - b.x)
+  let dy = float(a.y - b.y)
+  return -(arctan2(dy, dx) / pi) * 180.0 + 90.0
+
+proc direction*(ax, ay: int16, b: TPoint): float64 {.inline.} =
+  return direction((ax, ay), b)
+
+proc direction*(a: TPoint, bx, by: int16): float64 {.inline.} =
+  return direction(a, (bx, by))
+
+proc direction*(ax, ay: int, b: TPoint): float64 {.inline.} =
+  return direction((ax.int16, ay.int16), b)
+
+proc direction*(a: TPoint, bx, by: int): float64 {.inline.} =
+  return direction(a, (bx.int16, by.int16))
+
+
+# convert degrees to radians
+template toRad*(a: float64): expr =
+  (a * pi / 180.0)
+
+# convert radians to degrees
+template toDeg*(a: float64): expr =
+  (a * 180.0 / pi)
+
 
 # create TColor
 proc color*(r: int, g: int, b: int): TColor {.inline.} =
diff --git a/lib/entity.nim b/lib/entity.nim
index ad2cff6..1ba6ae6 100644
--- a/lib/entity.nim
+++ b/lib/entity.nim
@@ -1,12 +1,13 @@
 import
-  sdl,
+  sdl, math,
   common, engine, image, collider
 
 type
 
   PEntity* = ref TEntity
   TEntity* = object of TObject
-    fX, fY: int16
+    fX, fY: float
+    fXi, fYi: int16
     fLayer*: int
     updateLayer*, deleteEntity*: bool
     kind*: string
@@ -21,14 +22,16 @@ proc free*(obj: PEntity) =
 
 proc init*(obj: PEntity,
            graphic: PImage,
-           x: int16 = 0'i16,
-           y: int16 = 0'i16,
+           x: float = 0.0,
+           y: float = 0.0,
            layer: int = 0,
            kind: string = "",
            collider: PCollider = nil
           ) =
   obj.fX = x
+  obj.fXi = x.round.int16
   obj.fY = y
+  obj.fYi = y.round.int16
   obj.fLayer = layer
   obj.updateLayer = false
   obj.deleteEntity = false
@@ -38,19 +41,20 @@ proc init*(obj: PEntity,
 
 
 proc newEntity*(graphic: PImage,
-                x: int = 0,
-                y: int = 0,
+                x: float = 0.0,
+                y: float = 0.0,
                 layer: int = 0,
                 kind: string = "",
                 collider: PCollider = nil
                ): PEntity =
   new(result, free)
-  init(result, graphic, int16(x), int16(y), layer, kind, collider)
+  init(result, graphic, x, y, layer, kind, collider)
+
 
 # render
 
 proc renderEntity*(obj: PEntity) =
-  obj.graphic.blit(obj.fX, obj.fY)
+  obj.graphic.blit(obj.fXi, obj.fYi)
 
 method render*(obj: PEntity) {.inline.} =
   obj.renderEntity()
@@ -66,33 +70,51 @@ method update*(obj: PEntity) {.inline.} =
 # get/set methods
 
 method getRect*(obj: PEntity): TRect {.inline.} =
-  result.x = obj.fX + obj.graphic.x
-  result.y = obj.fY + obj.graphic.y
+  result.x = obj.fXi + obj.graphic.x
+  result.y = obj.fYi + obj.graphic.y
   result.w = UInt16(obj.graphic.surface.w)
   result.h = UInt16(obj.graphic.surface.h)
 
 
 method getCircle*(obj: PEntity): TCircle {.inline.} =
   result.r = UInt16(min(obj.graphic.surface.w, obj.graphic.surface.h)/2)
-  result.x = obj.fX + result.r + obj.graphic.x
-  result.y = obj.fY + result.r + obj.graphic.y
+  result.x = obj.fXi + result.r + obj.graphic.x
+  result.y = obj.fYi + result.r + obj.graphic.y
 
 # x
-method x*(obj: PEntity): int {.inline.} =
+method x*(obj: PEntity): float {.inline.} =
   return obj.fX
 
+method xi*(obj: PEntity): int {.inline.} =
+  return obj.fXi
+
 method `x=`*(obj: PEntity, value: int) {.inline.} =
-  obj.fX = int16(value)
-  obj.collider.x = obj.fX + obj.graphic.x
+  obj.fX = float(value)
+  obj.fXi = int16(value)
+  obj.collider.x = obj.fXi + obj.graphic.x
+
+method `x=`*(obj: PEntity, value: float) {.inline.} =
+  obj.fX = value
+  obj.fXi = value.round.int16
+  obj.collider.x = obj.fXi + obj.graphic.x
 
 
 # y
-method y*(obj: PEntity): int {.inline.} =
+method y*(obj: PEntity): float {.inline.} =
   return obj.fY
 
+method yi*(obj: PEntity): int {.inline.} =
+  return obj.fYi
+
 method `y=`*(obj: PEntity, value: int) {.inline.} =
-  obj.fY = int16(value)
-  obj.collider.y = obj.fY + obj.graphic.y
+  obj.fY = float(value)
+  obj.fYi = int16(value)
+  obj.collider.y = obj.fY.round.int16 + obj.graphic.y
+
+method `y=`*(obj: PEntity, value: float) {.inline.} =
+  obj.fY = value
+  obj.fYi = value.round.int16
+  obj.collider.y = obj.fYi + obj.graphic.y
 
 
 # layer