CG Class 27, Mon 2018-12-03

1   OpenGL in Guha vs WebGL in Angel

  1. Guha, the text I used before Angel, uses OpenGL. Angel uses WebGL.

  2. OpenGL has a C API; WebGL uses Javascript.

  3. That OpenGL is the obsolete version 2; WebGL is based on the current OpenGL 3.

  4. OpenGL 2 has an immediate mode design: you draw things and they are forgotten.

    In WebGL you send buffers to the GPU and then draw them.

  5. OpenGL has compute shaders and geometry shaders. They fill in points along Bezier curves and draw trimmed NURBS.

  6. A NURBS surface is a 2D parametric surface in 3D (or 4D if homogeneous).

    A trim line is a 1D parametric curve in the the 2D parameter space of the surface.

    The trim lines cut around the outside of the desired region and also cut out holes.

    This is a powerful technique.

2   Chapter 15 slides

  1. You do not need to learn most of those slides. Later I'll summarize what you need.
  2. 15_1 Global rendering.
  3. 15_2 Ray tracing.
  4. 15_3 What's next?.