Making Things See

Project 6: Invisible Pencil

This application is going to take the tracking interface we created in the last section and turn it into a drawing program. We’ll still track the closest point that the Kinect can see, but now instead of simply displaying it as a circle on top of the depth image, we’ll use that point to draw a line.

To draw a line in Processing, you need two points. Processing’s line function takes four values: the x- and y-coordinates of the first point followed the x- and y-coordinates of the second point. It draws a line on the screen that connects these two points that you give it. To transform our closest point tracking code into drawing code, we’ll need to draw a line on each frame instead of a circle. And we’ll want our line to ...