--output with multiple file groups could create multiple png outputs

[mwestphal]

Context
F3D supports opening multiple file groups and saving png outputs, lets bring these features together in order to be able to save multiple images when opening multiple file groups

Suggested solution
When opening multiple file groups, rely on filename templating to write different files.

eg :

f3d ./files/* --output=output_{model}.png

Could create output_model1.png, output_model2.png ..

[mwestphal]

https://gitlab.kitware.com/f3d/f3d/-/issues/119

[Meakk]

I think it's out of scope, one can just do:

for f in ./files/*; do
    f3d $f --output=output_$f.png
done

[mwestphal]

Still, current behavior is not super nice:

f3d ./files/* --output=output.png output a screenshot of the first file.

[mwestphal]

@Meakk @snoyer I'm thinking of closing this. nobody ever requested it and I think #46 is more important anyway. What do you think ?

[mwestphal]

Need #653 to move forward

[snoyer]

I think --output should just warn if there's model files that haven't used in the render.

However if you really want multiple outputs you could use a templating mechanism as proposed in #1194 so that f3d a.gltf b.gltf --output={model}.png generates a.glft.png and b.gltf.png

[mwestphal]

related to #46