CG Class 7, Mon 2017-09-18

W Randolph Franklin, RPI

Table of contents

1 Serpinski gasket links fixed

There were some obsolete and suboptimal links in class04 and 05 and the syllabus. I (think I've) fixed them now. Sorry.
The gasket programs are here.
My firefox has stopped running webgl. However chrome works.

SIGGRAPH is the world's leading CG conference. I'll show various videos from it.

There are several ways; here is the easiest.
Reference: http://www.w3schools.com/js/js_output.asp
Examples to do inside square.js:
1. window.alert('this is an alert');
2. window.alert('vertices length: ' + vertices.length + ' 1: ' + vertices[1]);
Note that you can write variable values as well as strings.
Another way is to write to the console log thus:

console.log('this is a log message');
In firefox, you can display the log window with F12.
An advantage of the log is that you see all the messages together.
I'll demo these methods.

For today's demo program, I'll modify triangle to add a slider that controls the amount of green to add to the triangle color.

The amount of green will be read from a slider.
Scrounge your slider code from gasket5.
The value will be transmitted to the fragment shader in a uniform variable.
Scrounge around in Angel's examples to see how to use a uniform variable. (I grepped for 'uniform').

We'll continue with the textbook powerpoint slides.

I'm replacing the Angel lecture at Incremental and Quaternion Rotation, with my own material. Feel free to read ahead.