Which line algorithm uses an integer decision variable to choose pixels?
A Painter’s algorithm
B Flood fill
C Ray casting
D Bresenham algorithm
Answer: D. Bresenham algorithm. Bresenham’s line algorithm updates an error term incrementally using integer arithmetic.
For DDA line drawing, how many steps are used?
A |dx| × |dy|
B min(|dx|, |dy|)
C |dx| + |dy|
D max(|dx|, |dy|)
Answer: D. max(|dx|, |dy|). DDA takes the larger coordinate difference as its step count so increments stay at most one pixel.
Which line-clipping method assigns region codes to endpoints?
A Phong coefficients
B Cohen–Sutherland outcodes
C Bresenham error codes
D Bézier weights
Answer: B. Cohen–Sutherland outcodes. Cohen–Sutherland uses outcodes to classify endpoints against clip boundaries.
When can Cohen–Sutherland immediately accept a line?
A One endpoint is inside
B Both endpoints are outside
C Both outcodes are zero
D The slope is zero
Answer: C. Both outcodes are zero. Zero outcodes place both endpoints inside the clipping region.
Line endpoints sharing which bit guarantees immediate rejection?
A Common outside bit
B Equal endpoint depths
C Different endpoint colors
D Shared vertex index
Answer: A. Common outside bit. A shared set bit means both endpoints lie outside the same clip half-plane.
How does polygon clipping proceed in Sutherland–Hodgman?
A One boundary at a time
B Color channel
C One texture at a time
D One vertex at a time
Answer: A. One boundary at a time. The algorithm clips the polygon successively against each boundary of the clip region.
How are scan-line fill spans determined?
A Edge intersections
B Camera positions
C Texture colors
D Vertex normals
Answer: A. Edge intersections. For each scan line, intersections with polygon edges define the spans to fill.
Line clipping keeps which part of a segment?
A Brightest portion
B Inside portion
C Longest portion
D Outside portion
Answer: B. Inside portion. Clipping retains the portion that lies within the view region.
Window-to-viewport mapping mainly combines which operations?
A Rotate and shade
B Scale and translate
C Clip and tessellate
D Sample and blend
Answer: B. Scale and translate. The mapping scales window coordinates to viewport dimensions and translates them to viewport position.
Object coordinates enter world space through which transform?
A Texture transform
B Projection transform
C Object-to-world transform
D Raster transform
Answer: C. Object-to-world transform. The model transform places local object coordinates into the world coordinate system.
World coordinates map into camera space through which matrix?
A Object scale matrix
B Texture matrix
C Viewport matrix
D Inverse camera transform
Answer: D. Inverse camera transform. The view transform applies the inverse of the camera’s world-space pose.
Camera coordinates become clip coordinates at which stage?
A Projection matrix
B Normal matrix
C Texture matrix
D Model matrix
Answer: A. Projection matrix. The projection matrix maps view-space geometry into homogeneous clip space.
For column-vector 2D homogeneous translation, where are tx and ty stored?
A First row
B Last row
C Last column
D Main diagonal
Answer: C. Last column. With column vectors, translation occupies the final column of the 3×3 affine matrix.
Positive rotation in a standard Cartesian plane is which direction?
A Counterclockwise
B Toward the origin
C Downward
D Clockwise
Answer: A. Counterclockwise. Positive angular rotation follows the counterclockwise convention.
Nonuniform scaling generally changes what?
A Camera focal length
B Relative proportions
C Pixel count only
D Object position only
Answer: B. Relative proportions. Different scale factors along axes change the shape’s relative proportions.
Wireframe rendering emphasizes what?
A Filled surface colors
B Texture samples
C Polygon edges only
D Depth values
Answer: C. Polygon edges only. Wireframe rendering draws edges without filling polygon interiors.
In flat shading, which normal typically represents a polygon?
A One normal per pixel
B One face normal
C One texture normal
D One camera normal
Answer: B. One face normal. Flat shading uses a single face normal for the polygon’s lighting.
Gouraud shading interpolates what across a polygon?
A Face connectivity
B Texture dimensions
C Vertex intensities
D Camera positions
Answer: C. Vertex intensities. Gouraud shading computes lighting at vertices and interpolates the resulting intensities.
Phong shading interpolates what across a polygon?
A Vertex indices
B Clip outcodes
C Pixel depths
D Surface normals
Answer: D. Surface normals. Phong shading interpolates normals and evaluates lighting across the surface.
Lambert diffuse brightness depends on which term?
A |N − L|
B N × L
C N + L
D max(N·L, 0)
Answer: D. max(N·L, 0). Lambert diffuse response is proportional to the nonnegative dot product of the normal and light direction.
For a Phong highlight, which directions should align?
A View and reflected ray
B Vertex/index alignment
C Near/far alignment
D Texture/viewport alignment
Answer: A. View and reflected ray. In the Phong model, the highlight peaks when the viewing direction aligns with the reflected light direction.
Alpha blending combines which colors?
A Texture and depth
B Foreground and background
C Near and far
D Vertex and normal
Answer: B. Foreground and background. Alpha blending combines a source color with the destination color according to opacity.
Nearest-neighbor filtering selects what at a texture sample?
A Longest edge
B Four texels
C Average mip levels
D Nearest texel
Answer: D. Nearest texel. Nearest-neighbor filtering uses the texel closest to the sampled texture coordinate.
Bilinear texture filtering blends how many nearby texels?
A Eight mip levels
B One polygon face
C Four neighboring texels
D Two distant texels
Answer: C. Four neighboring texels. Bilinear filtering interpolates among four neighboring samples in one texture level.
Why are mipmaps useful during strong minification?
A Extra polygon edges
B Larger depth values
C Higher camera speed
D Prefiltered texture levels
Answer: D. Prefiltered texture levels. Mipmaps provide prefiltered, reduced-resolution levels that lessen aliasing during minification.