BSCS Bachelor of Science in Computer Science: Computer Graphics Fundamentals Questions 2 — Questions and Answers
Question 1: Which shading model computes illumination at each vertex and interpolates colors across a polygon?
- Phong shading
- Gouraud shading (Correct answer)
- Flat shading
- Ray shading
Correct answer: Gouraud shading
Gouraud shading interpolates per-vertex lighting across the polygon surface, producing smoother results than flat shading.
Question 2: In homogeneous coordinates, what does the w-component equal to 0 represent?
- A point at the origin
- A point at infinity (direction vector) (Correct answer)
- A normalized vector
- An invalid coordinate
Correct answer: A point at infinity (direction vector)
A homogeneous coordinate with w=0 represents a direction vector or point at infinity rather than a finite point.
Question 3: What is the purpose of the z-buffer algorithm in 3D rendering?
- Anti-aliasing edges
- Depth sorting for correct occlusion (Correct answer)
- Computing surface normals
- Texture coordinate mapping
Correct answer: Depth sorting for correct occlusion
The z-buffer stores the depth of the closest fragment at each pixel, ensuring correctly occluded surfaces are hidden.
Question 4: Which transformation preserves angles and ratios of distances along parallel lines?
- Perspective projection
- Affine transformation (Correct answer)
- Projective transformation
- Shear transformation
Correct answer: Affine transformation
Affine transformations (translation, rotation, scaling, shear) preserve parallelism and ratios of collinear distances.
Question 5: In Bezier curves, what role do control points that lie OFF the curve play?
- They define knot vectors
- They attract the curve toward them without the curve passing through (Correct answer)
- They define end conditions only
- They split the curve into segments
Correct answer: They attract the curve toward them without the curve passing through
Off-curve control points act as magnetic attractors, pulling the Bezier curve toward them without requiring the curve to interpolate those points.
Question 6: What does the term 'aliasing' refer to in the context of rasterization?
- Color banding from limited bit depth
- Jagged staircase artifacts on diagonal edges (Correct answer)
- Z-fighting between coplanar surfaces
- Texture stretching on angled surfaces
Correct answer: Jagged staircase artifacts on diagonal edges
Aliasing in rasterization produces jagged staircase artifacts (jaggies) because a continuous edge is approximated by discrete pixels.
Question 7: Which color model is most appropriate for describing light emitted by displays?
- CMYK
- HSL
- RGB (Correct answer)
- YCbCr
Correct answer: RGB
RGB is an additive color model matching how display devices emit red, green, and blue light to form colors.
BSCS Bachelor of Science in Computer Science: Computer Graphics Fundamentals Questions 2
Which shading model computes illumination at each vertex and interpolates colors across a polygon?