Attributes

"attributes" are inputs to a vertex shader that get their data from buffers.

to each vertex, an attribute might be a point of vec3, or a float, or other vectors.

Triadica tried some ways of reprensenting that, while trying not to be slow.

Simplest way of passing attributes is create a list and pass points directly:

object $ {}
  :draw-mode :triangles
  :points $ []
    [] 1 2 3
    [] 4 5 6
    [] 4 5 6

notice that :points and :indices are used by twgl.js for creating a_position attributes.

internally it's turning into AugmentedTypedArray that consumes by twgl.js .

object $ {}
  :draw-mode :triangles
  :attributes $ {}
    :positions $ []
      [] 1 2 3
      [] 4 5 6
      [] 7 8 9

To make it easier to support complicated logics, there are other ways of passing attributes.

`:packed-attrs`

To make it easier, we can collect attributes of a single vertex in a map, and nest them in lists:

object $ {}
  :draw-mode :triangles
  :packed-attrs $ []
    []
      {}
        :position $ [] 1 2 3
        :color_type 0
      {}
        :position $ [] 4 5 6
        :color_type 1
      {}
        :position $ [] 7 8 9
        :color_type 2

This could make building some shapes that requires multiple attributes easier by aligning the length of arrays, with some extra performance penalties.