sparkler: add virtual flag to particle_props_t

The burst particle abused a zero mass to circumvent the effects of aging.

Instead use an explicit virtual flag to suppress aging, change busrt_cb
to ignore all virtual particles instead of only its center.  Previously
burst_cb would thrust other bursts like any other particle, and this was
incorrect.  Now burst centers are always stationary, even when they overlap
other bursts.

0 files changed, 0 insertions, 0 deletions