[R] How to chain user mouse handlers in rgl

[Duncan Murdoch]

On 01/03/2008 5:41 AM, Dieter Menne wrote:
> Dear Rglers,
> 
> With rgl, I would like to set marker when a button is pressed, but leave the
> standard trackball handling otherwise. Thanks to Duncan and Oleg for helping
> me handling key down.

I don't think there's currently an easy way to do that.  What you would 
have to do is to replicate the trackball handler in yours.  (You can see 
what it does in the src/rglview.cpp in the rgl source.)

If you want to write the R code (and docs for it) to fix this, I'll put 
it into rgl.

Duncan Murdoch

> How do I say in a custom mouse handler "after having done your work, forward
> to standard trackball once only"? The example below shows the idea, but it
> works only once, then reverts to standard trackball handling.
> 
> Dieter
> 
> #----------------------
> library(rgl)
> r3dDefaults
> open3d()
> shade3d(cube3d(color=rep(rainbow(6),rep(4,6))))
> 
> 
> btn3d <- function() {
>   begin <- function(x, y) {
>     # Add checking for key down later
>     cat(x,y,"\n")
>     # Forward to trackball (no easier way?)
>     newhandler <- par3d("mouseMode")
>     newhandler[1] <- "trackball"
>     par3d(mouseMode =  newhandler)
>    }
>    rgl.setMouseCallbacks(1, begin)
>  }
> 
> btn3d()
> 
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