C O M P U T E R G R A P H I C S Guoying Zhao 1 / 14 C O M P U T E R G R A P H I C S Guoying Zhao 1 / 14 Going-through

C O M P U T E R G R A P H I C S Guoying Zhao 2 / 14 C O M P U T E R G R A P H I C S Guoying Zhao 2 / 14 L1 Terms  Computer graphics?  Interactive computer graphics?  CAD, CAM, NPR  SIGGRAPH The history of computer graphics: Pioneer Questions  Graphics Vs. Image ? Computer Graphics Vs. Image Processing  Computer Graphics Applications?  Differences between Steroscopic Display and Three Dimensional Viewing Devices

C O M P U T E R G R A P H I C S Guoying Zhao 3 / 14 C O M P U T E R G R A P H I C S Guoying Zhao 3 / 14 L2 Term:  Ray tracing, radiosity, resolution, frame buffer, refresh rate, raster, pixel, scan line, rasterization Questions:  Elements of Image formation  Additive color and subtractive color  Pinhole Camera model  Advantages of Synthetic Camera Model  Pipeline architecture? Explaination of each step

C O M P U T E R G R A P H I C S Guoying Zhao 4 / 14 C O M P U T E R G R A P H I C S Guoying Zhao 4 / 14 L3-L4 OpenGL is a state machine? Understanding of OpenGL code.

C O M P U T E R G R A P H I C S Guoying Zhao 5 / 14 C O M P U T E R G R A P H I C S Guoying Zhao 5 / 14 L5: Geometry and Representation  Elements of geometry: Scalars, Vectors, Points  What characteristics of polygons would be usually considered: Simple, convex, flat.  How to judge if a polygon is convex?  Convex Hull  What is Homogeneous Coordinates? why do we need it?

C O M P U T E R G R A P H I C S Guoying Zhao 6 / 14 C O M P U T E R G R A P H I C S Guoying Zhao 6 / 14 L6: Transformation Transformations  translation, rotation, scaling, shear, and their Homogeneous Coordinates transformation matrix  can build arbitrary transformation matrices from simple transformations Building models  outwardly facing polygons? how to judge?  Geometry vs Topology? Giving example?  Data structures for building polygonal models: Vertex list vs. Edge list?  Vertex Arrays?

C O M P U T E R G R A P H I C S Guoying Zhao 7 / 14 C O M P U T E R G R A P H I C S Guoying Zhao 7 / 14 L7: Viewing Classical viewing:  Basic elements involved in Viewing. –One or more objects - A viewer with a projection surface –Projectors that go from the object(s) to the projection surface  Two basic viewing: parallel projection and perspective projection  Taxonomy of Planar Geometric Projections: characteristics of each view. Vanishing points? Computer Viewing  Fundamental operations of viewing in pipeline architecture? Positioning the camera, Selecting a lens, clipping  Projection Matrices: Rather than derive a different projection matrix for each type of projection, we can convert all projections to orthogonal projections with the default view volume. Understand how to do so for Orthogonal Normalization, Oblique Projections, Perspective projections?

C O M P U T E R G R A P H I C S Guoying Zhao 8 / 14 C O M P U T E R G R A P H I C S Guoying Zhao 8 / 14 L8: HSR  What is Hidden Surface Removal?  Why to do it? –Avoiding ambiguity –Improving rendering rates  Algorithms? Object-space algorithms Area-Subdivision Method Depth Sorting Method Image-space algorithms Ray Casting Method Z-buffer  Especially z-buffer algorithm?

C O M P U T E R G R A P H I C S Guoying Zhao 9 / 14 C O M P U T E R G R A P H I C S Guoying Zhao 9 / 14 L9: Shading Light Sources? Point, spotlight, ambient Phong model? (Diffuse, Specular, Ambient, I =k d I d l · n + k s I s (v · r ) a + k a I a ) explain each term? Modified phone model (Blinn-phone model): half-way vector, half-way angle, Replace (v · r ) a by (n · h ) b Phong shading vs. Gouraud shading

C O M P U T E R G R A P H I C S Guoying Zhao 10 / 14 C O M P U T E R G R A P H I C S Guoying Zhao 10 / 14 L10: Texture Mapping and Blending Texture mapping Mapping Methods: Texture Mapping, Environment Mapping, Bump Mapping Coordinate systems involved? Two-part mapping? Using cylinder or sphere as intermediate object? Strategies for second step? Point sampling vs area averaging? Magnification, Minification? Mipmapping? Compositing and blending: Opacity and Transparency? Depth cueing? How can we use alpha blending for antialiasing?

C O M P U T E R G R A P H I C S Guoying Zhao 11 / 14 C O M P U T E R G R A P H I C S Guoying Zhao 11 / 14 L11: 2D graphics-1 Line Drawing Algorithms  DDA algorithm  Midpoint algorithm  Bresenham’s line algorithm Circle Generating Algorithms  Bresenham’s circle algorithm  Extension to Ellipse drawing

C O M P U T E R G R A P H I C S Guoying Zhao 12 / 14 C O M P U T E R G R A P H I C S Guoying Zhao 12 / 14 L12: 2D graphics-2 Polygon Filling  Scan-line Conversion Approaches  Area Filling Approaches  How to judge a point inside or outside a polygon Scan-line Conversion Approaches?  4-connected area and 8-connected area? Antialiasing  What’s aliasing?  Antialiasing Methods? Clipping  Line clipping: Cohen-Sutherland, Cyrus-Beck/Liang-Barsky Parametric Line Clipping

C O M P U T E R G R A P H I C S Guoying Zhao 13 / 14 C O M P U T E R G R A P H I C S Guoying Zhao 13 / 14 L13: Hierarchical model Symbol-Instance Table? pros and cons? Graph? Tree? DAG model? Simple tree model for humanoid? DOF? Depth first tree transversal algorithm? Tree traversal function: explicitly (stacks, depending on particular tree) vs. implicitly (recursively) Left-child right-sibling structure? Preorder Traversal?

C O M P U T E R G R A P H I C S Guoying Zhao 14 / 14 C O M P U T E R G R A P H I C S Guoying Zhao 14 / 14 L14: Particle system and animation Scene Graph? Separator Nodes in scene graph? Particle system? Repulsive forces vs. Attractive forces? Spatial subdivision technique? Animation? computer animation? Technologies?