Hierarchies & Higher Level Structures
Problem: how to collect many disparate models into a coherent whole?
E.g. at origin, far way, really small, very big models
We use model hierarchies
Root node corresponds to complete model
Demo: GLUT light and materials demos
Problem: how to color models so they look "realistic"
E.g. back side dark, far away darker, shiny surfaces, light sources
Several approaches, in two groups
Detailed, photorealistic approaches
Basic idea: don't render stuff that will not be visible anyway
Each face has a front side, and a back side
Compare the normal from the front face to the vector to the eye
Simple way to do this: after project to unit c
Problem: do two polygons intersect?
Trivial accept on intersect (slower)
Compare each edge in one polygon to every edge in the other
If any one pair intersects, the polygons intersect
If no pair inters
Occluders: cast shadows
Receivers: have shadows on them
Point light sources: make hard shadows
Area light sources: make soft shadows
Umbra: the fully shadowed region
Penumbra: the partially shadowed region
Existing APIs do not
Problem: how to do reflections on shiny objects?
Model whats out there as textures
From each point on geometry, look up the texture color needed
We are talking about mirror like specular reflections here,
A router is blasting out IP packets whose total length (data plus header) is
1,024 bytes. Assuming that packets live for 10 sec, what is the maximum data line speed
the router can operate at without danger or cycli