Indeed, currently you can only have one Input slice mask.
You can draw it with a pencil though.
If you need such complex masks you might be better off drawing the slice itself with the
polygon tool, or applying the
masks on the clip or layer level.
If you could let us know more about what you are trying to accomplish, that would be a great help trying to understand your workflow, and we could maybe figure out a proper solution for it.
Software developer, Sound Engineer,
Control Your show with ”Enter” - multiple Resolume servers at once - SMPTE/MTC column launch
try for free:
http://programs.palffyzoltan.hu