CS 184: MIDTERM-EXAM TOPICS 2009

Computer graphics hardware and its abstract view:

• Display devices: calligraphic, raster.
• Frame buffer organization, color map.

Scene description format:

• Hierarchical scene composition.
• Groups and instance calls.
• Dynamic, time-varying, constructs.

Modeling and object representations:

• CSG, Brep, Voxels,
• Winged-edge data structure
  
• Procedural object generation, e.g., sweep operations;
• Instantiations and hierarchy,
• Abstractions, level of details.
• Degrees of freedom.

2D & 3D transformations, matrix representation, compound transforms;

• Rigid-body transforms and affine transforms,
• Change of coordinate systems, reinterpretation of coordinates:
• Window-to-Viewport transformation.
• Homogeneous coordinates: purpose, implementation.

        Splines:

• Parameterized polynomial curves; in particular, cubics.
• Approximating splines vs. interpolating splines
• Cubic Hermite and Bézier curve segments, and methods to assemble them.
• G0, G1, G2, C1, C2, continuity, and conditions for achieving them.
• Sketching curve segments from points; finding the point for some value t=[0,1]
• DeCasteljeau algorithm for the construction for Bézier curves.
• Concept of approximating complicated curves with many (cubic) spline segments.
• Cubic B-spline, how to make smooth closed curves.
• Bicubic Bézier patches. B-spline surfaces.
  
• Catmull-Clark and Loop subdivision surfaces.

Clipping: points, lines, polygons, hierarchies:

•  Sutherland-Hodgman clipping,
  
• Use of bounding boxes.
• Front- and Back-plane clipping.

Modeling, viewing/rendering pipeline:

• Master-, world-, image-, NDC-, screen-coordinate systems; transformations between them.
• Efficient and logical ordering of the various functions in the viewing pipeline.

Polygon rasterization:

• Pixel sampling,
• Inside/outside determination by parity/winding_#,
• Scan-line algorithm.

Visibility determination; hidden feature elimination:

• Backface elimination; face normals: formula by Martin Newell .
• Painter's algorithm.
  
• Z-buffer algorithm for hidden feature elimination, scan-line implementation.

Illumination models:

• The various types of light.
• Surface models, idealized and real:
  
Lambert surfaces, ideal mirrors, Phong lighting model;
diffuse-, mirror-, and (Phong)specular- reflection;  metal vs. plastic.

Rendering / shading techniques:

• The classical rendering pipeline.
  
• Scan-line rendering algorithm.
• Principles of  ray-casting.
• Principles of  ray-tracing.
• Reflected and refracted rays.
• Distribution ray-tracing
  
• Area light sources.
• Gouraud shading, Phong shading, and their limitations
• Surface Decorations: Texture mapping; bump mapping, displacement mapping, environment mapping.