timing bug when example boots

[esromneb]

When the example webpage boots there is a timing bug where the rainbow can render after a resize and cause an issue.

Correct (guess):
c++ resize 400
c++ draw rainbow
js draw rainbow
c++ resize 10
c++ draw ray
js draw ray

Incorrect (guess):
c++ resize 400
c++ draw rainbow
c++ resize 10
js draw rainbow

[esromneb]

But was reproduced by pasting this scene:

{
  "camera": {
    "loc": [5, 0, 0],
    "dir": [-1, 0, 0],
    "rot": [0, 0, 1],
    "depth": 6
  },
  "global": {
    "color": [0.2, 0.2, 0.2],
    "c": 10,
"scale":166.6666666,
"alpha":true,
"x":8,
"y":8
  },
  "spheres": [
{
      "rad": 3.8,
      "loc": [-4, 0, 0],
      "ambient": 1.1,
      "specular": 1.46,
      "reflected": 0,
      "transmitted": 0.0,
      "diffuse": [1.4, 0.0, 0.0],
      "n": 32
    }
  ],
  "lights": [{
    "dir": [-0.4, -1, 0.6],
    "color": [20, 20, 20]
  }
]
}

And then refreshing in firefox. On version a8088d7 and alpha doesn't affect this

Built with NOOPT=1 and edited this into ray.html:

function renderFrame() {
  var dst = Module.canvasData.data;
  if (dst.set) {
    console.log(renderFrameData.length); // add this
    dst.set(renderFrameData);
  } else {
    for (var i = 0; i < renderFrameData.length; i++) {
      dst[i] = renderFrameData[i];
    }
  }
  Module.ctx.putImageData(Module.canvasData, 0, 0);
  renderFrameData = null;
}