Hardware: General
Architecture | Alignment and Masking
| Rigging lasers | Computer-controlled
lasers
Software: The choice of LithTech
| 2D input ->3D world | Iterations on interactivity
| Implementing a storyline
Interface between the 2D input (lasers) and the 3D world (LithTech)
An important challenge in our interactivity was to take the 2D information gathered through laser detection and transform it so as to be able to project it in our 3D world run by LithTech. The following diagram explains this process:
The laser server runs the detection program, which returns the x and y coordinates of the detected laser points. The LithTech server takes this 2D coordinate to cast a ray that runs through the focal point of the viewing frustum and the detected point on the near clipping plane. This insures that the distortion caused by perspective does not produce inaccurate transposition between 2D and 3D. Once the ray has been cast, we check whether it intersects with a polygon of an object whose type can be determined. That is, we can choose to handle intersection with dinosaurs and ignore everything else. Then, at the point of intersection, we draw a sphere - it is the magic bio-bubble that will bring the dinosaurs back to life!
