Re: Gen patch-a-day


Forums > Gen > Gen patch-a-day
February 28, 2012 | 6:10 pm

Here’s one for the gaffers and camera assistants in the house! By that I mean that this patch requires an image that is evenly-lit and properly exposed. That’s why there’s no jit.qt.grab, because it would be too easy to use your laptop’s built-in camera with your face lit by the computer screen. Yuk!!! Also shooting at a fairly high resolution will make the details nicer.

The patch is based on the idea that all human skin, despite large differences in saturation and brightness, has approximately the same hue. We use that fact to apply a blur to the skin only, leaving details like eyes, nose, and mouth sharp. So the technique can be used to smooth out blemishes or–if you push it–create a cartoon effect.

In certain cases, for example very light or very dark complexions, you may find it easier to use the little gswitch object to look at the alpha channel while you adjust the threshold.

It’s worth taking the time to dig into the jit.gl.pix objects for some useful tips. The blur uses the cell object to achieve sub-pixel displacement, regardless of image size. The technique for creating this cheap blur can also be used to do more specialized blurs. Our saturation boost is done in the hsl colorspace. We smooth the edges of our key with the smoothstep object.

If you have experience working with compositing/finishing applications like Shake, Nuke, Smoke, or even Da Vinci Resolve, you’ll appreciate working with a nodal interface like Max. Now that gen brings that nodal interface to the world of openGL hacking, you can easily bring cool film techniques to your real-time video processing. Just don’t forget to use your camera and lighting skills, too.