Stencil Buffer test not used to cull light volume fragments which do not contain scene geometry within them. #2
Description
Even the Z discard is commented out
https://github.com/osense/irrRenderer/blob/master/bin/shaders/light_point.frag#L25
Stencil tests+Z tests will enable discarding of unshadeable pixels directly in hardware before reading from a Z-texture
Some details of deferred implementations for anyone who'd want to fix this