Graphics Reference
In-Depth Information
203
4
=
2
1
=
DET
36
242
003
2
1
36
2
3
=
1
042
2
=
20 3
42
1
36
1
9
r
=
1
=
20 2
200
4
1
36
4
9
s
=
22
=
240
r
=
1
9 and s
=
4
9 confirms that the ray intersects the triangle. The point of intersection is given by
2
3 2 i
p
=
t
+
v
=
4 j
+
4 j
+
2 k
4
3 i
8
3 j
4
3 k
=
4 j
+
+
4
3 4
3 4
P
=
3
Using Eq. (6.31), we find that
k
=
2 j unchanged
m
=
8 i unchanged
i
j k
n
=
2
42
=−
6 i
+
2 j
+
10 k
3
12
n
·
p 21 =
6 i
+
2 j
+
10 k
·
2 j
+
4 k
=
36
1
36 8 i
2
3
=
·
3 i
j
+
2 k
=
1
36
1
9
r
=
6 i
+
2 j
+
10 k
·
2 j
=
1
36 8 i
4
9
s
=
·
2 i
4 j
+
2 k
=
which are identical to the previous results.
6.13 A point inside a triangle
Having discovered how to test whether a line intersects a triangle, it is an opportune moment
to describe how to test whether a point is inside or outside a triangle. Once again, we draw
upon barycentric coordinates to reveal the solution.
 
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