FX Composer

No console output at all? No warning?

It could be that panda doesn’t pass data to it when it’s out of vshader or fshader function (which makes sense). Therefore, you might have an empty modelview matrix, and the model thus doesn’t show up.

that can explain the second case ( a parameter declared outside the shader function) since if I declare a parameter that I don’t use, my model is still visible.

For the first case, (a bad named but useless parameter). I assume that panda doesn’t send the bad parameter input which cause the function to be invalid, which makes OpenGL discard the model.

I mean, that makes sense. What’s bothering me ( apart from the fact that I would like to do that) is that it doesn’t throw any error.

I just tried it. It really throws an error.

At first glance, the model doesn’t show up (because there’s no valid shader responsible for making the model appear) but if you look in the console, some errors should be there.

I still can’t see them, but maybe it’s because of my Config.prc ?
notify-level warning
#notify-level-glgsg debug
default-directnotify-level warning