CS 184: COMPUTER GRAPHICS


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Lecture #21 -- Mon 4/11/2011.

Warm-up questions:

How many degrees of freedom are associated with:

-- all planar quadrilaterals in 3-space?

-- with the mechanical 2D linkage below?




Which point maps into the origin (0,0,0)
in the complete perspective transform
into the full (±
1) canonical view cube?


How to find the solutions:   Transform some key sample points by the given matrix and see what happens; then solve the resulting equation.

The Modern Rendering Pipeline

Let's look again at the overview of the Classical Rendering Pipeline.
In the middle portion we see the three options for doing the necessary  clipping  (discussed last time).
In the last few stages of the pipeline the most advances have occured in the last decade.
The are due to the availability of ever more powerful (and more general)  GPUs,
and the introduction of ever more sophisticated  shader  programs.

A brief review of the development of computer graphics hardware.

This is a subset of the slides presented by David Luebke, Nvidia,
as an invited keynote speaker at the Interactive 3D Graphics and Games conference, San Francisco, Feb. 19, 2011.
David Luebke graciously allowed me to use some of his material,
but he did not want me to put it on the web in the public domain -- so pay attention! )


Let's briefly recap the surface decoration effects that you had an opportunity to explore with Assignment #8:
Texture mapping:
Bump mapping:
Displacement mapping:
Environment mapping:

Implementation of all these techniques:
This typically occurs through special graphics hardware: GPU's (Graphics Processing Units),
using special Shader programs that work on a  per-vertex
per-fragment or per-pixel  basis.
Example of a typical processing pipeline (as seen by DirectX)
Another schematic view of the same pipeline segment


On 4/7/2011 I received a copy of a brand new textbook that has just been published:
E. Angel and D Shreiner: "Interactive Computer Graphics: A top-down apporach with shader-based OpenGL" 6th Edition, Addison Wesley, 2011.
(If I could turn back the clock by 6 months, I would use this as the textbook for CS 184.)
It does a good job guiding you to these newer developments in the rendering pipeline.
(And it would have made assignment #8 somewhat less confusing).


The Course Project

CS 184 is now officially a DESIGN-Course!
ABET requirements specify, that such courses:
-- have a  DESIGN-Project  and
-- teach and test  Technical Communication Skills.

Start planning for it now!  Consult Project Page!


Smooth Surfaces

A Bezier patch is just the external product of two Bezier curves.
But it is tedious to assemble many of them into a smooth surface.

A B-spline surface is just the external product of two B-spline curves.
It is difficult to make closed surfaces of higher genus with multiple tunnels or handles.
Here is a generalization to arbitrary topologies:

Subdivision Curves and Surfaces

A good introductory booklet on Splines with interactive demos:
"Interactive Curves and Surfaces," (with Multimedia Tutorial on CAGD), A. Rockwood and P. Chambers, Morgan Kaufman Publishers, Inc.
[ This was used in recent offerings of CS 284. ]


Reading Assignments:

Shirley:  2nd and 3rd Ed: Ch.15 :  But without the detailed math relating to basis functions  (we cover that in  CS 284)


Start of the CS 184 Course Project:
Form your teams: 1, 2, or 3 persons; select a tentative design task; write a short proposal
(100-300 words) before Friday April 15, 11:00pm


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