This is a simple application that loads an OBJ file and an environment map and calculates & displays the corresponding 3rd order spherical harmonics coefficients for it. The coefficients can also be modified at runtime to see the effect of each coefficient.
Here is a dog statue (that I attempted to scan a few years ago) in a room environment:
And here is a simple sphere in an outdoor environment:
Linux dependencies for glfw: xorg-dev libgl1-mesa-dev
git clone --recursive https://github.com/ands/spherical_harmonics_playground.git
cd spherical_harmonics_playground
cmake .
make
./playground
dickyjim has collected various resources regarding spherical harmonics on his blog.