Camera functions to convert between world and screen coordinates

DepthsBelow/DepthsBelow/Camera.cs

@@ -28,6 +28,16 @@ namespace DepthsBelow
 			Speed = 300;
 		}
 
+		public Vector2 ScreenToWorld(Vector2 screenPos)
+		{
+			return Vector2.Transform(screenPos, Matrix.Invert(Transform));
+		}
+
+		public Vector2 WorldToScreen(Vector2 worldPos)
+		{
+			return Vector2.Transform(worldPos, Transform);
+		}
+
 		public void Update(GameTime gameTime)
 		{
 			float elapsed = gameTime.ElapsedGameTime.Milliseconds / 1000.0f;
@@ -48,7 +58,6 @@ namespace DepthsBelow
 				Matrix.CreateTranslation(new Vector3(-Position.X, -Position.Y, 0))
 				* Matrix.CreateRotationZ(Rotation)
 				* Matrix.CreateScale(Zoom)
-				//* Matrix.CreateTranslation(new Vector3(
 			;
 		}
 	}

DepthsBelow/DepthsBelow/MouseInput.cs

@@ -68,9 +68,10 @@ namespace DepthsBelow
 			}
 
 			// Grid highlighting
-			Point currentGrid = Grid.ScreenToGrid(new Vector2(ms.X + core.camera.Position.X, ms.Y + core.camera.Position.Y));
-			Vector2 currentScreen = Grid.GridToScreen(currentGrid);
-			gridRectangle = new Rectangle((int)currentScreen.X, (int)currentScreen.Y, Grid.TileSize, Grid.TileSize);
+			Vector2 clickWorldPos = core.camera.ScreenToWorld(new Vector2(ms.X, ms.Y));
+			Point clickGridPos = Grid.WorldToGrid(clickWorldPos);
+			Vector2 rectWorldPos = Grid.GridToWorld(clickGridPos);
+			gridRectangle = new Rectangle((int)rectWorldPos.X, (int)rectWorldPos.Y, Grid.TileSize, Grid.TileSize);
 
 			lastMouseState = ms;
 		}