# CG Lecture 3, Thurs 2016-09-01

1. Today will end at 5 because the President is holding a reception.

2. If you're interested, the Fall 2014 version of this course is here. This year is 90% the same.

3. Here is My local cache of Angel's web site . It may be faster to access.

(Several times, I've been glad to have a local cache of some web site, because the web site later vanished.)

4. Linear algebra tutorial

1. For students confused by the linear algebra questions on homework 1, the following may help:

2. Also see wikipedia.

3. Some older graphics texts have appendices summarizing the relevant linear algebra.

4. The scalar (dot) product is needed to do things like this:

1. compute how a ball bounces off a wall in pong
2. compute lighting effects (how light reflects from a surface)
5. The cross product's applications include:

1. compute torque and angular momentum.
2. compute the area of a parallelogram.

It is the only operator that you'll probably ever see that is not associative. Ax(BxC) != (AxB)xC.

6. The triple product (A.BxC) computes the volume of a parallelepiped.

5. We'll continue with the textbook powerpoint slides.

1. 2_2, Programming with WebGL Part 1: Background.
2. 2_3, Programming with WebGL Part 1: Background
3. 2_4, Programming with WebGL Part 2: Complete Programs
4. 2_5, Programming with WebGL Part 2: Complete Programs