My example with sprite animation in pure WebGL 1.0 doesn't work on Plunker

[8Observer8]

My example doesn't show animation and doesn't print any errors to the console: https://plnkr.co/edit/RuOBTnWsiwk3uMln?preview

Exactly the same example works on PlayCode: https://playcode.io/1524054

Using only PlayCode is not a solution. I need both for a reservation.

Source on GitHub with instruction to build with Rollup: https://github.com/8Observer8/run-animation-texture-packer-webgl-js

[ggoodman]

That's quite strange. I'm unfortunately not familiar enough with webgl to tell you what's going on but here are some observations:

1. The issue seems to reliably reproduce when the preview pane is initially shown (either on initial load or after toggling it).
2. The issue does not reproduce when the preview is refreshed.

That sort of thing makes me think that there is a race condition somewhere in the code that is making an assumption about load ordering that doesn't always hold true.

[8Observer8]

I remembered a similar problem you helped me solve a year ago with window.onresize: Three.js doesn’t start rendering automatically on Plunker

I added this window.onresize handler and the problem was solved: https://plnkr.co/edit/RuOBTnWsiwk3uMln?preview

    window.onresize = () => {
        const w = gl.canvas.clientWidth;
        const h = gl.canvas.clientHeight;
        gl.canvas.width = w;
        gl.canvas.height = h;
        gl.viewport(0, 0, w, h);
        mat4.lookAt(viewMatrix, [0, 0, 50], [0, 0, 0], [0, 1, 0]);
        mat4.mul(projViewMatrix, projMatrix, viewMatrix);
    };
    window.onresize(null);