P8 Project

• Project title: 1050 project P8: Active Zones for CSG
• Names of the team members
• Short description of the assignment
• Definition of the active zone and explanation of how it is computed
• A short description of how/why it is used in the applet
• An example of a CSG expression and of the active zone expression for a primmitive
• Reference to the Active Zone paper with a link to http://www.gvu.gatech.edu/~jarek/
• Window with a running applet (described in the next slide)
• Explanations of the User Interface commands for dragging/chaning primitives
• Link to the course code

Start with your P3 assignment with a CSG editor
You will not need it tree editing (but it is nice if you have it)
You need to be able to render a CSG defined region and to circulate which one is the current primitive and to move the primitive
Implement a recursive procedure that compute the path to each primitive and stores it with the primitive (you can represent the path as a string of characters or bits).

Let A be the current primitive, Z its active zone, and S0 the region defined by the expression S whith A replaced by the empty set
Render the background in white, S0 in blue, AZ in red, Z–A in green. Remember that S0 and AZ are disjoint and that their union is S.
Hardwire your code with an interesting CSG tree and select the default current primitive so that it has at at least 3 branching nodes, two of which being Boolean expression with two or more primtives, with at least one i-node and one u-node.

In the project web page, print the CSG expression, say which primtive is the defailt active primitive, provide the CSG expressions for its I-zone, U-zone, active zone, and S0. Include an image showing the corresponding regions and explain the color coding.