The Ygdrasil User's Guide

the selector node

You can also choose children by number instead of by name. This is handy if you have a lot of selection options, because you don't have to explicitly name all the nodes. It's also useful if you're controlling the selector using variables - for instance, you could set up a value node as a counter to step through the different selections.

The children of the selector can be any node type, not just object nodes. If you want to make the selector choose between whole groups of multiple nodes, just make each group a transform node. The transform would be the child of the selector, so when it gets selected, it turns on all of its children too.

The selector is not just a visibility control - it completely activates and deactivates its children. So, nodes like lights, triggers, and animations are deactivated when they are not selected. You can then swap whole sections of your scene in and out, deactivating parts of the world that you don't need. Sometimes this can make complex scenes run faster.

However, nodes like timers, animations, and sounds will not automatically start when they are selected - you do have to send them their start and stop messages after selecting them to start them running. This is particularly true of sounds, since sound playback is really handled by a completely separate program from YG itself.

Using the selector

Note that the pointAtTrigger also makes the small shapes grow slightly when you just point at them, which lets the user know that they are "active" in some way.

Also, the first child of the selector is just "node ()". this is a completely empty YG node, and is used to make the selector begin with nothing shown.

initial state	click on the sphere	click on the cone	click on the torus

#include "User0"

light(position(1 -1 1))
light(position(-1 -.5 .75),diffuse(.4 .4 .4))


pointAtTrigger (when(start,ball.size(1.1)),
		when(stop,ball.size(1)),
		when(button1,shapeSelector.select("bigball")))
{
	object ball (file("redsphere.b3d"),position(-3 5 3))
}

pointAtTrigger (when(start,cone.size(1.1)),
		when(stop,cone.size(1)),
		when(button1,shapeSelector.select("bigcone")))
{
	object cone  (file("greencone.b3d"),position(0 5 3))
}

pointAtTrigger (when(start,donut.size(1.1)),
		when(stop,donut.size(1)),
		when(button1,shapeSelector.select("bigdonut")))
{
	object donut (file("purpletorus.b3d"),position(3 5 3))
}

selector shapeSelector ()
{
	node()
	object bigball (file("redsphere.b3d"),position(0 15 5),size(4))
	object bigcone  (file("greencone.b3d"),position(0 15 5),size(4))
	object bigdonut (file("purpletorus.b3d"),position(0 15 5),
		size(4),orientation(15 0 0))
}

selector ()
{
	childnode0 ()
	childnode1 () 
	childnode2 ()
	...
}