If the following error occurs, hardware acceleration may be disabled.
Cannot read property ‘VERTEX_SHADER’ of undefined
Please enable hardware acceleration on your browser.
[Firefox]
Please take a look here
https://support.mozilla.org/ja/kb/performance-settings
[Google Chrome]
Your issue may be resolved by doing the following:
1. Please enter the following line to open Chrome's settings
chrome://flags/#ignore-gpu-blacklist
2. Enable "Override software rendering list"
3. Restart Google Chrome