For openSUSE Slowroll run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:illuusio/openSUSE_Slowroll/home:illuusio.repo
zypper refresh
zypper install glm
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:illuusio/15.6/home:illuusio.repo
zypper refresh
zypper install glm
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:illuusio/15.5/home:illuusio.repo
zypper refresh
zypper install glm
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:illuusio/15.4/home:illuusio.repo
zypper refresh
zypper install glm