# Shared Flashcard Set

## Details

ED2 Test2 - 2
sajdkas
7
Anthropology
01/25/2010

Term
 How do you detect degenerate triangles?
Definition
 you find 2 edges of the triangle and crossing the edges. if the result of the norm of the vector is 0 it is degenerate
Term
 What is BSP?
Definition
 It is splitting the world up in a way using partitions\splits using planes rather than splitting up the world by boxes or cubes, which allows us to cull pats of hte world and the objects in it which reduce the amount of information that needs to be processed at one time.
Term
 What is the Plane equation?
Definition
 Ax + By + Cz - D = 0; ABC is the normal of the plane D is the distance to the plane/plane offset XYZ is the point on the plane if the result is zero
Term
 What are the types of diving planes?
Definition
 Arbitrary/General: No restrictions placed on how they are generated Hint Planes: placed by the level designed in the map editing tool Auto-partitioning/polygon aligned: planes are derived from the input geometry. Mose useful method for building a BSP tree, also used exclusively with indoor or enclosed environments
Term
 What are Node Based Trees?
Definition
 Stores polygons/geometry in the nodes and leaves Classic form of the BSP tree Allows for quick rendering of the scene from back to front Not a good choice for collision detection Tree construction ends when no polygons to split by remain
Term
 What are leaf-based trees?
Definition
 Stores polygons/geometry exclusively in the leaves polygons in the leaves form "clusters" Clusters form convex subsections of the world good for collision detection good for frustum culling no control over draw order of individual faces Splitting stops when Leaf contains less than some minimum number of polys a fixed tree depth has been reached a good dividing plane cannot be found
Term
 What is the Sutherland-Hodgman Polygon-Clipping algorithm?
Definition
 0: When both points lie in front of the plane, the end point is output 1: When the edge goes from in front of the plane to behind the plane, the intersection point is the output 2: When both points lie behind the plane, nothing is output 3: When the edge goes from behind the plane to in front of the plane, both intersection and the endpoint are output
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