I previously had allegro-5-2-5-0 running under ubuntu 18.04 and everything was working fine, had been for a long time. For various reasons I decided to upgrade and have come up against a problem.

Made a clean install of ubuntu 20.04, loaded everything back and decided to go for a later allegro, 25.2.6.0. Download and expanding directories all went without a problem but when trying to build the libraries, examples etc. with

mkdir build
cd build
cmake ..

I get an error after a few seconds:

CMake Error at CMakeLists.txt:712 (message):
X11 support currently requires OpenGL or OpenGL ES support.

Surprisingly I cannot find any reference to this, that seems a simple error, on the internet.

I found a libOpenGL.so.0.0.0 on my system but really know nothing about OpenGL so just don't know what to try next.

The problem is consistent.

I'm enclosing three files that may be relevant, you can see where the error occurred in CMakeLists.txt, The other two are the logs produced.

Any help much appreciated

Alexx

To build Allegro from source you need to install (a lot of) dependencies, they are all listed in the documentation (but without Ubuntu-specific package names) - I think this is a complete list for Ubuntu:

https://github.com/liballeg/allegro_wiki/wiki/Install-Allegro-from-source-on-Ubuntu

Allegro always keeps up to date, but Ubuntu always uses deprecated dependencies, so you need to manually download the dependencies into the 'deps' directory.

Thanks for help.

I just went through steps 1 and 2 in Elias's link, and then where I had got the error before ( on "cmake .." ) went through without a problem.