Graphics Reference
In-Depth Information
X
(
x
,
y
,
z
)
Plan view
screen
(
x
p
,
y
p
)
x
−
x
p
Z
d
z
Y
(
x
,
y
,
z
)
Side view
screen
(
x
p
,
y
p
)
y
y
p
Z
d
z
Fig. 7.32.
The plan and side views for computing the perspective projection trans-
form.
which, after all, is rather elegant. Notice that this transform takes into account
the sign change that coours with the
x
-coordinate. Some topics will leave this
sign reversal until the mapping is made to screen coordinates
7.11 Summary
The purpose of this chapter was to introduce transforms and matrices - I hope
this has been achieved. This end of the chapter is not really the end of the
subject, as one can do so much with matrices and quaternions. For example,
it would be interesting to see how a matrix behaves when some of its elements
are changed dynamically, and what happens when we interpolate between a
pair of quaternions. Such topics are addressed in later chapters.
