World Co-Ordinates for Mouse in Screen Space for 2D

Well I managed to fix the problem I was having in my previous post.  This works for both translations in X and Y, and also for camera scale (zoom level).  I haven’t figured out how to include rotation yet but as that isn’t particularly important for what I’m trying to do I’ll let that slide for now.

Assuming you have a 2D camera class that implements a transformation matrix like so:

transform = Matrix.CreateScale(
new Vector3((scale * scale * scale),
(scale * scale * scale), 0))
* Matrix.CreateRotationZ(rotation)
* Matrix.CreateTranslation(new Vector3(
position.X, position.Y, 0));

The world space mouse co-ordinates can be obtained like so:

float mouseWorldX = (mouse.X - camera.Position.X) /
 (float)Math.Pow(camera.Scale, 3);
float mouseWorldY = (mouse.Y - camera.Position.Y) /
 (float)Math.Pow(camera.Scale, 3);

Tagged with: C# • XNA

Filed under: Game Design

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