First I tried detecting the “shaking motion” of an image target, by comparing an image target’s position change per unit time. I could use this trick to implement the action of leaving a trail of gunpowder from the firework. But this didn’t work because the frame rate of AR camera was extremely low, so if I actually shake the image target in front of the camera, it appears discontinuous and Vuforia would no longer recognize it.
So I tried something else- I managed to add two image targets to the scene and Vuforia could recognize both of them. I then wanted to get their relative positions but I was stuck. Some Googling gave me several fixes but none of them worked and I was frustrated for a while until I realized it was caused by a bug in my own code. Oops.
There’s really not much image to show here because most of all this was just Googling and debugging. To see my progress you can check out my next few blog posts.