1   Iclicker questions

1. Why does WebGL have the triangle-strip object type, in addition to the triangle type?
   1. It leads to smaller, faster, graphics objects.
   2. It leads to bigger, faster, graphics objects.
   3. It's not possible to split some complicated polygons into lots of simple triangles, but you can split them into triangle-strips.
   4. The standards writers were being paid by the word.
2. What is the physical principle underlying LCD?
   1. Fire an energetic electron at a rare earth atom and a photon of light is emitted.
   2. Plowing your family farm as a kid can suggest an way to invent electronic television.
   3. A solution of corkscrew shaped molecules can rotate polarized light.
   4. Putting your finger close to a capacitor can change its capacitance.
   5. If two coils of wire are close, then an alternating current in one can induce a current in the other.
3. Standards ...
   1. allow programmers to move between projects
   2. allow different types of hardward to be substituted in.
   3. ..... operating systems ......
   4. allow vendors to lock in customers.
   5. can prevent the latest HW from being used to its fullest.
4. Color printing on a sheet of paper exemplifies
   1. additive color
   2. subtractive color
   3. multiplicative color
   4. divisive color
   5. exponential color
5. Red is a primary color of which color space?
   1. additive color
   2. subtractive color
   3. multiplicative color
   4. divisive color
   5. exponential color
6. Major components of the WebGl model as discussed in class are:
   1. Objects, viewer, light sources, planets, material attributes.
   2. Still cameras, video cameras, objects, light sources.
   3. Objects, viewer, light sources, material attributes.
   4. Colored objects, black and white objects, white lights, colored lights
   5. Flat objects, curved objects, near lights, distant lights.

2   SIGGRAPH 2017 videos

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

1. BendSketch: Modeling Freeform Surfaces Through 2D Sketching.

   My local copies (MP4 and WEBM) are here.

3   Textbook slides

We'll continue with the textbook powerpoint slides.

1. 3_1, Programming with WebGL Part 3: Shaders
2. 3_2, Programming with WebGL Part 3: Shaders (2nd set with this title)
3. 3_3, Programming with WebGL Part 4: Color and Attributes
4. 3_4, Programming with WebGL Part 5: More GLSL
5. 3_5, Programming with WebGL Part 6: Three Dimensions
6. 3_6, Programming with WebGL Part 6: Three Dimensions ctd

4   Today's original demo program

For today's demo program, I'll modify triangle to add a slider that skews a vertex. Then we can maybe rotate.

5   Text chapter 3 programs

Now, we'll see how the programs in <https://wrf.ecse.rpi.edu/Teaching/graphics/SEVENTH_EDITION/CODE/03/>`_ work.

triangle, cad1 and cad2 are simple interactive drawing programs.

File locations:

1. Textbook site.
2. My local web copy .
3. There's another copy on RCS at /afs/rpi.edu/home/56/frankwr/public_html/ECSE-4750/Angel/7E/03
4. which is also visible on the web.