Method setDebug

src/ui.js:240–244

(visible, text = '')

  }

  setDebug(visible, text = '') {
    const el = this.$('debug');
    el.classList.toggle('hidden', !visible);
    if (visible) el.textContent = text;
  }

  showWebglError() {
    this.$('webgl-error').classList.remove('hidden');