callbacks: User callbacks on mouse events

In rgl: 3D Visualization Using OpenGL

Description

Set and get user callbacks on mouse events.

Usage

rgl.setMouseCallbacks(button, begin = NULL, update = NULL, end = NULL, 
                      dev = cur3d(), subscene = currentSubscene3d(dev))
rgl.getMouseCallbacks(button, 
                      dev = cur3d(), subscene = currentSubscene3d(dev))

rgl.setWheelCallback(rotate, 
                      dev = cur3d(), subscene = currentSubscene3d(dev))

rgl.getWheelCallback(dev = cur3d(), subscene = currentSubscene3d(dev))

Arguments

button	Which button?
begin	Called when mouse down event occurs
update	Called when mouse moves
end	Called when mouse is released
rotate	Called when mouse wheel is rotated
dev, subscene	The rgl device and subscene to work with

Details

The set functions set event handlers on mouse events that occur within the current rgl window. The begin and update events should be functions taking two arguments; these will be the mouse coordinates when the event occurs. The end event handler takes no arguments. The rotate event takes a single argument, which will be equal to 1 if the user pushes the wheel away by one click, and 2 if the user pulls the wheel by one click.

Alternatively, the handlers may be set to NULL, the default value, in which case no action will occur.

If a subscene has multiple listeners, the user action will still only be called for the subscene that received the mouse event. It should consult par3d("listeners") if it makes sense to take action on the whole group of subscenes.

The get function retrieves the callbacks that are currently set.

Value

The set functions are called for the side effect of setting the mouse event handlers.

The rgl.getMouseCallbacks function returns a list containing the callback functions or NULL if no user callback is set. The rgl.getWheelCallback returns the callback function or NULL.

Author(s)

Duncan Murdoch

See Also

par3d to set built-in handlers

Examples

 pan3d <- function(button, dev = cur3d(), subscene = currentSubscene3d(dev)) {
   start <- list()
   
   begin <- function(x, y) {
     activeSubscene <- par3d("activeSubscene", dev = dev)
     start$listeners <<- par3d("listeners", dev = dev, subscene = activeSubscene)
     for (sub in start$listeners) {
       init <- par3d(c("userProjection","viewport"), dev = dev, subscene = sub)
       init$pos <- c(x/init$viewport[3], 1 - y/init$viewport[4], 0.5)
       start[[as.character(sub)]] <<- init
     }
   }
   
   update <- function(x, y) {
     for (sub in start$listeners) {
       init <- start[[as.character(sub)]]
       xlat <- 2*(c(x/init$viewport[3], 1 - y/init$viewport[4], 0.5) - init$pos)
       mouseMatrix <- translationMatrix(xlat[1], xlat[2], xlat[3])
       par3d(userProjection = mouseMatrix %*% init$userProjection, dev = dev, subscene = sub )
      }
   }
   rgl.setMouseCallbacks(button, begin, update, dev = dev, subscene = subscene)
   cat("Callbacks set on button", button, "of rgl device", dev, "in subscene", subscene, "\n")
 }
 shade3d(icosahedron3d(), col = "yellow")
 # This only works in the internal display...
 pan3d(1)

rgl documentation built on Feb. 1, 2021, 3:01 a.m.