Support other sources as input images

[zed9h]

If other input images are specified, they appear as a browse button to load a static image files.
It would be nice if other source could also be selected (for dynamic masks, for instance)

[nleseul]

Could be useful. Complexity depends on how easily OBS exposes the output texture for specific sources. The properties would also need some way to identify textures that should be populated from a source rather than a texture. (Shader annotation syntax?)

[khlorghaal]

afaik from skimming the source, this repo is mostly a passthrough for OBS's existing filter plugin API, exposed to allow dynamic loading.

imo the shaderfilter's usecase is as a simple "filter", more complex effects should use external programs to construct their own pipelines, to be captured by OBS