Advanced Computer Graphics – Midterm Take-Home Exam

due by Monday 2019. 10. 28.

1. [20pts] Explain the following transformations that are applied in the rendering pipeline. a) model transform (model
space→world space), b) view transform (world space→camera space), and c) projection transform (camera space→
projection image space).

2. [10pts] Explain how distributed raytracing can generate soft shadows.

3. [10pts] Explain how the bounding volume hierarchy can speed up the ray tracing.

4. [10pts] Compare the bump mapping and the displacement mapping.

5. [10pts] Compare the nearest neighbor and the linear interpolations in the texture mapping.

6. [20pts] We want to run the scan-line algorithm for the following triangle. The edge information in the edge table is
(ab: ∆y=2, ∆x=-3, x=6), (ac: ∆y=4, ∆x=1, x=6), (bc: ∆y=3, ∆x=3, x=3). Write the changes of the active edge list
for each scan-line, and specify the pixels inside of the triangle.

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7. [20pts] Suppose that we use a partial adjacency representation to store triangle meshes. It is composed of an edge
table, a face table, and a vertex table. The edge table contains vertex and face adjacency, the face table contains
vertex and edge adjacency, and the vertex table contains face adjacency. Face split is an operation which splits a face
into two faces. One face, one vertex, and two edges are added to the triangle mesh after a face split. Figure a) shows
a triangle mesh and its partial adjacency representation. Figure b) is the triangle mesh after the face split of F1. Write
the partial adjacency representation of b).

Face Table
Edge Table
F0: v0,v1,v2; e0,e1,e2
e0: v0,v1; F0,Æ;
F1: v1,v3,v2; e1,e3,e4
e1: v1,v2; F0,F1;
Vertex Table
e2: v0,v2; F0,Æ;
v0: F0
e3: v1,v3; F1,Æ;
v1: F1,F0
e4: v2,v3; F1,Æ;
v2: F0,F1
v3: F1
a) A triangle mesh before the triangle split and its partial adjacency representation

b) A triangle mesh after the triangle split of F1

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