CSUDH Computer Science Department
CSC
461 Computer Graphics I
(
Fall
200
5
)
Final Examination
(1
0
:
0
0
a
m
–
12:00
pm
,
December
12
, 200
5
)
1.
(
2
0 points,
4
points each)
Briefly e
xplain
1)
Additive color model and subtractive color model
2)
P
rojection normalization
an
d projection pipeline
3)
Opacity and RGBA color
4)
Local rendering and global rendering
5)
Advantages and disadvantages of orthogonal projection
2.
(20 points)
Assume that
a unit cube
is rotated
with 5
degree
s each step
around a given
line x+
z
=
2 and y
=1 at the lo
cation (
1
,
1
, 1)
and alternately shrinks and grows with 50%.
Outline how to implement this rotating and scaling cube in OpenGL
by
(specifying the
parameters of transformation functions used, if any)
1)
(4 points) Outlining the
main function
2)
(6
points) Outli
ning the display callback
3)
(6
points) Outlining the idle callback
4)
(4 points) Outlining the reshape callback
3.
(
20
points)
The OpenGL function
gl
Frustum
requires
that
six parameters
be
used to
determine the projection matrix and the viewing volume. Assu
me the projection plane
is the default plane z = 0). Consider the function call
gl
Frustrum
(
1
,
5
,
3, 9
,
2
,
6
)
.
1)
(
2
points)
Explain the difference of
glFrustrum
from the function
glPerspective
.
2)
(6 points)
Explain the six parameters of the
glFrustrum
functi
on
by illustrating the
view volume
3)
(6 points)
Describe the t
hree
steps to
find
the projection
matrix
4)
(6
points)
Find the final projection matrix
4.
(20
points) The Phong reflection model
uses the four vectors and supports the three
types of material

ligh
t interactions.
CSC461
Final Examinat
ion
(
Fall
200
5
)
1
1)
(3 points) One of the four vectors is the reflection vector. What are the other three
vectors?
2)
(3 points) What are the three types of material

light interactions?
3)
(4 points) What are the assumptions in the Phong reflection model with whic
h the
reflection vector can be computed with the given other vectors?
4)
(4 points) Describe the
four
steps of shading in OpenGL.
5)
(6 points) Show how the reflection vector is computed in terms of other vectors.
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