Graphics Reference
In-Depth Information
However, in lighting calculations, the vector
v
in
is often reversed and points toward the light,
which means that its sign must be reversed in these equations:
v
out
=
2
n
ˆ
·
v
in
n
ˆ
−
v
in
(5.11)
n
v
in
·
t
−
r
p
=
r
+
n
·
v
in
We use Eq. (5.11) later in Section 10.2.
