Computer Science
455
Instructor:
R. P. Burton
Second Quiz
February 4-5,
2008
Name _________________________________________ Score
____________/31
- The ink is an ink
jet printer is deflected
- magnetically
- electrostatically
- mechanically
- (it is not deflected;
it is deposited in a raster fashion on a selenium drum)
(b)
- The writing device
in a mechanical plotter is
- an ink pen
- a laser
- a carbide-tipped
stylus
- (any of the above)
(d)
- The thrust of CS
455 is
- special-purpose
software packages
- general-purpose
software packages
(b)
- World coordinate
space is the coordinate space of
- original definitions
of basic shapes
- the application
- a generic output
device
- a specific output
device
(b)
- The primary objective
of standards is
- control
- profit
- interoperability
(c)
- What is scan conversion?
- presenting the contents
of the frame buffer on the display
- producing the contents
of the frame buffer
- conversion from
metric graphics to nonmetric (typically US) graphics
(b)
- The line segment
goes between (0,0) and (50, -60). Which of the following happens
at every step of the execution of the DDA algorithm?
- x increases by 1
- y increases by 1
- x decreases by 1
- y decreases by 1
- (none of the above)
(d)
- The line segment
goes between (0,0) and (50, -60). Which of the following happens
at every step of the execution of the symmetric
DDA algorithm?
- x increases by 1
- y increases by 1
- x decreases by 1
- y decreases by 1
- (none of the above)
(e)
- Which if the following
is NOT an advantage of the Bresenham circle-drawing algorithm?
- takes advantage
of the 8-way symmetry of a circle
- requires only simple
arithmetic operations
- requires no calculation
of initial values
- always increments
(or decrements) x or y
- (all are advantages)
(c)
- If multiple processors
are available for drawing a Bresenham line segment, the segment should
be broken
- roughly equally
among the processors
- at the points where
the decision variable cycles start
(a)
- To find the memory
location in the frame buffer for the first pixel representing a line,
it is necessary to calculate the row (row number x width) and add to
that the column number. To find the memory location of the next
pixel
- requires less calculation
- requires roughly
the same calculation
- requires more calculation
(a)
- What’s wrong
with solving the implicit equation for a circle to determine y values
as a function of x values?
- nothing
- it’s slow, but
uniform
- is fast, but not
uniform
- it’s both slow
and nonuniform
- it doesn’t really
make a circle
(d)
- What’s wrong
using the parametric equation for a circle to determine x and y values?
- nothing
- it’s slow, but
uniform
- is fast, but not
uniform
- it’s both slow
and nonuniform
- it doesn’t really
make a circle
(b)
- What’s wrong
using the DDA technique for a circle to determine x and y values?
- nothing
- it’s slow, but
uniform
- is fast, but not
uniform
- it’s both slow
and nonuniform
- it doesn’t really
make a circle
(e)
- What’s wrong
using the Bresenham technique for a circle to determine x and y values?
- nothing
- it’s slow, but
uniform
- is fast, but not
uniform
- it’s both slow
and nonuniform
- it doesn’t really
make a circle
(a)
- The Bresenham techniques
____ extend to other conics such as ellipses, parabolas, and hyperbolas.
- do
- do not
(a)
- For drawing a hollow
circle, all the pixels should
- be centered as close
as possible on the actual circle
- be contained inside
the actual circle
- be on the outside
of the actual circle
(b)
- Which of the following
is NOT a reason for tessellating a polygon into a collection of triangles?
- scan conversion
algorithms for modern graphics hardware typically are written for triangles
- to support subsequent
antialiasing
- triangles are planar,
whereas polygons may not be
(b)
- Concavities in
polygons can be detected by looking at cross products.
- true
- false
(a)
- Inside-outside
tests done with the odd-even approach can produce results which are
different from those done with the nonzero winding number approach,
even when there are no roundoff problems.
- true
- false
(a)
- The plane Ax +
By + Cz + D = 0 has at least one feature different from the plane –Ax
– By – Cz – D = 0.
- true
- false
(a)
- What is the sum
of A, B, C, and D for the plane containing the vertices (1,2,3), (4,5,6),
and (6,5,4)?
- 0
- 6
- 12
- 24
- (none of the above)
(a -6x +
12y -6z)
- What is a polymarker?
- a marker with RGB
components
- a collection of
markers
- an attribute of
a polygon describing its visibility (or invisibility)
(b)
- Graphics systems
are not capable of presenting either points or line segments.
At best, they can present small or narrow areas.
- true
- false
(a)
- The appropriate
representation of a point on a display surface has the attributes of
position, color, and reflectivity.
- true
- false
(b)
- What is the meaning
of “A” as in RGBA?
- intensity
- black
- white
- transparency
- (there is no such
thing as “RGBA”)
(d)
- A graphics system
which can display a scene consisting of 256 colors from a pallet of
more than 16 million is no more reasonable than a box of 200 crayons
of which only a few can be used to produce a drawing.
- true
- false
(b)
- What kind on end
caps are produced when the DDA or Bresenham line-drawing algorithm as
adapted to double/triple/quadruple/… thickness lines?
- butt
- round
- projected end
- (none of the above)
- (The DDA and Bresenham
algorithms do not lend themselves to thicker lines)
(d)
- What is the slope
of a line perpendicular to a line with slope m?
- -m
- 1/m
- -1/m
(c)
- The scan-line fill
technique discussed in class accommodates all of the following EXCEPT
- concave polygons
- polygons with holes
- polygons with horizontal
edges
- (no exceptions here)
(d)
- The scan-line fill
technique requires a sorted edge table, but the active edge list
(with “top” and “bottom” pointers) serves only to increase its
efficiency.
- true
- false
(b)