Ubuntu 20.04.1 LTS ffglut can not run

Hello there. I get the following error after install FreeFem++ 4.7 on ubuntu 20.04.

It can not plot a picture. Can you help me please?

Thanks in advance.

You need to provide a plot to ffglut before saying it cannot run.
For example, could you see if the following file can be displayed?

$ ffglut file.edp

file.edp (41.0 KB)

Thanky you! I have run it, but it gives nothing!

Now I try to uninstall it and reinstall, it works. Many thanks.

you can add debuT option

fglut -vv /Users/hecht/Downloads/file.edp >~/Desktop/ffglut.edp

and the result file are : ffglut.edp (3.3 KB)

if the file is empty => ffglut is wrong …