[Updated for QLab 4.1 13 JUL 17]
This workspace creates a projected simulation of a follow spot that can be controlled using a Wacom tablet. This is another workspace which uses OSCULATOR. For details of what Osculator is, and how it works, translating MIDI fades in QLab to OSC messages refer to Fading OSC.
Here it is in action:
How It Works: To use Osculator to generate OSC messages, to control QLab, it is necessary to set up an Osculator routing to QLab.
Open Osculator, click on the Parameters gear icon, select OSC routing, and enter: osc.udp://localhost:53000 in the Target OSC URL.
Close the Parameters window. Press Caps Lock and draw something with the pen on your WACOM tablet.
The Osculator main window will immediately populate with all the recognised parameters for tablets. Your tablet may not support all parameters, in particular the cheaper ones don’t support pen tilt.
When you press CAPS LOCK, the cursor should lock in place, and the tablet output will be directed to Osculator. If your cursor is still moving, then your Wacom driver is out of date or incompatible. The Wacom driver for my very old Graphire 4×5 didn’t work, and there didn’t seem to be a more up to date version, but a quick trawl round the net quickly found a work around using the Wacom Driver 6.1.7-5 for Intuos 2. Of course, if you are going to use this method on a big production the bigger the tablet and the more features the better, but for experimenting, older models are available on ebay very cheaply.
You now need to set all the messages you want to use from the tablet, to Event Type OSC message, using the pop up menus, and then set a routing for each using the new pop up. In this example I am using the x and y pen positions and the pen tip pressure data.
When we select New… on the Value pop up menu we go to the OSC routing window.
We have previously set up QLab as the default target so all we need to do is click in the Rewrite Address column, in the Routes table, where it currently has ‘same address’. This will open the OSC Routing Editor Pane where the address can be rewritten to the OSC address for the Qlab parameter we want to control.
For the x axis: /cue/LIGHT/translationX
Repeat for the y axis with: /cue/LIGHT/translationY
Repeat for pressure with /cue/LIGHT/scaleX
Osculator produces an output of 0.0 to 1.0 for these parameters, so we now need to scale them to the numbers that Qlab will need as arguments to the OSC messages we have set.
Select the scalings page from the View menu (or press cmd-f, or click the curl icon next to the Chan. column in the main Osculator window).
For x and y we will need values to allow image placement any where on the surface we are using, and the pressure, which we are using to change the scale of the image will need a much smaller range. In the example I’ve used -600 min +600max for x and y and 0min to 2 max for scaleX
Save the Osculator file. Instructions for making this file open automatically with Qlab are contained in Fading OSC.
In QLab, open a new workspace and create a Title Cue. Number it LIGHT
Change the default text of the Titles Cue to a bullet point (alt-8)
Change the font size of the bullet point to 600
Engage Caps Lock, start the Titles cue and place the pen on the tablet. You should now have control of the white circles xy position on the surface and pressing harder on the pen stylus should make the circle bigger.
As a further refinement you can make the pen proximity start and stop the Titles cue.
Create a script cue, number it SPOT and add this script:
This creates a toggle that will start cue “LIGHT” if it is not running and stop it, if it is.
In Osculator change the event type of /wacom/.…../proximity to OSC Routing and rewrite the value to:
Engage CAPS LOCK again and bring the pen to the tablet.
You can change the shape of the spotlight beam using pictograph characters in the Titles cue text. The easiest way to access these is from the Character Viewer.
You can also use a white shape on a transparent background saved as a PNG with alpha in a Video cue instead of a Titles cue.
The two important things to remember are:
CAPS LOCK must be engaged to route the tablet output to Osculator.
The cue that contains your spotlight shape, whether Titles or Video, must be numbered LIGHT.
The workspace, and Osculator files can be downloaded Here
Cover Picture: Wilflet Public Domain from Wiki Commons