GetClientRect not pixel-perfect...

I've been making a 2D game with D3D and I'd like to implement the mouse to work with it. I've come up with an algorithm that works fine but the only problem is, is that I'm basing it off the size of the client area of the window. After looking long and hard to what is wrong, I found that getting the coordinates from GetClientRect() is slightly off. The X value is fine but the Y is off by ~20 when the window is at 800x800 (I have no menus or anything else special on the window). Is this true or am I going crazy and is there a way around this, because this takes away a lot of accuracy from the cursor.

Cheers.

Sounds like you either need to convert from screen coords to client coords or vice versa.

Just to note as well.....

Toolbars are included in the client area, that is; Y==0 is under the toolbar.

There's no toolbars or anything in there. I'll go back through my code later and make sure (I'm probably wrong). If there is, I'll try and rack up some proof.

As Bubba said it is probably a screen to client issue.

Mouse coords are relative to the top left of the screen (in screen coords).

Client rects are relative to the top left of the window's client area (excluding menu but not toolbar).

If your window is almost full screen you may not have noticed this.

Try converting using ClientToScreen() or ScreenToClient() .