use P2D / P3D without loadPixels

[clankill3r]

I want to dig into this later, but I was wondering if it is possible to use let's say the face detection with P2D instead of FX2D?
I need to use shaders too, so FX2D is not really an option for me.

But with P2D, I don't get any detections, unless I use loadPixels, which is really bad for the framerate.

I'm using 0.9.0.