[Angel p236-240; Foley p 229-242 ]
Introduction to Projection Transformations
Mapping: 
Projection: Mapping with m less than n
Planar Projection: maps 3D object onto plane
Parallel Projection
-
parallel lines preserve relative length
Perspective Projection
-
produces foreshortening
-
non-linear
A Taxonomy of Projections
A Basic Projection Matrix
Let's use the following example to construct a matrix that performs a perspective
transformation:
From similar triangles, we can see that y'/d = y/z
Thus, y' = yd/z
Similarly, x' = xd/z
We can express this in matrix form by altering the value of the homogeneous
parameter, h:
-
non-linear because of divide by h
-
can incorporate scaling
