Performance

The process of rendering can be divided into several passes:

declare tree of objects in Calcit-js
collect points and attributes into typed arrays(via twgl.js)
build WebGL program from shaders
call WebGL APIs to paint(via twgl.js)
optionally, extra framebuffers are used for bloom effect(via twgl.js)

Not all passes need to be re-computed when new frames are painted. In WebGL, we may put parameters that controls how object change in "uniforms", reuse shader programs and "attibutes". That means, when only last 2 steps need to be re-computed for new frames. When you are controlling the camera and the canvas being redrew, normally attributes do not need to be re-computed.

For imperative or OO programs, we may cache arrays for attributes directly. However in tree-shape DSLs, we need to cache them with some tricks. Caclit uses memoizations like in Clojure with the library memof.

; storing 1 item of caches for function
memof.once/memof1-call add3 1 2 3

; storing items of caches of a function by a given key, pass nil to skip
memof.once/memof1-call-by |a-unique-key add3 1 2 3

and each Triadica component is currently a function.

Uniforms

An extra field of injecting uniforms is provided called get-uniforms:

object $ {} (:draw-mode :triangles)
  :vertex-shader $ inline-shader "\"spin-city.vert"
  :fragment-shader $ inline-shader "\"spin-city.frag"
  :attributes attributes
  :get-uniforms $ fn ()
    js-object
      :citySpin $ :spin-city @*dirty-uniforms

in the function, dirty tricks can be used to access mutable states.