Question

I’m creating a GUI that has 1 to many OpenGL view forms. Now the basics are working, I have a list of Viewer Forms and each encapsulates an OpenTK.GLControl member in its designer class.

I need to get the actual cursor position in the window that I drag an icon onto so that when I release left click, it drops it into the GL window at that location. This is simplified from what it actually needs to do but just as a first step, once this can happen, the rest will come easily.

Now when I use GLControl.MousePosition.X, GLControl.MousePosition.Y to get the cursor position, it actual gives me the screen position, rather than the position in the window. Unfortunately this isn’t particularly useful for what I need to do.

I have looked at OpenTK.GameWindow.Mouse and this seems to work really well in my little test projects. It get’s the exact position of the cursor in the window. However, I can’t use the gamewindow in this project because gamewindow doesn’t have some of the more GUI form friendly things that GLcontrol has such as Dock, TabIndex, Paint and other GUI related members. (or at least I can’t seem to find any way for GameWindow to support them anyway, do let me know if I’m wrong)

So what I’m really asking is, does anybody have a really nice/simple way for me to get the window position of the cursor in a form using OpenTK.GLControl

In fact, even if it’s tricky please let me know 🙂 I just need to be able to do it!

Answer 1

Your problem lies outside the scope of OpenGL which only deals with drawing stuff amd OpenTK which glues OpenGL to .net. It’s a problem of Windows Forms. Windows Forms has a class Control with a method →PointToClient which you can use to transform from screen to client coordinates. If using OpenTK with GTK there is similar for GLWidget/Widget classes.