fix skirmisher sparks

vacuum_gambit.p8

@@ -605,7 +605,7 @@ function ship_m:move()
  self:maybe_shoot(self.main_gun)
  if (shoot_spec1 and self.special_guns) self:maybe_shoot(self.special_guns[1])
  if (shoot_spec2 and self.special_guns) self:maybe_shoot(self.special_guns[2])
- if (dx ~= 0 or dy ~= 0) spark(self.sparks, self.x + 4*self.size, self.y + 4*self.size, dx*2.5, dy*2.5, self.sparkodds)
+ spark(self.sparks, self.x + 4*self.size, self.y + 4*self.size, dx*2.5, dy*2.5, self.sparkodds)
  self.xmomentum = self:calc_velocity(self.xmomentum, dx)
  self.ymomentum = self:calc_velocity(self.ymomentum, dy)
 
@@ -1392,8 +1392,8 @@ ship_turret = mknew(ship_f.new{
 ship_skirmisher = mknew(ship_f.new{
  sprite=107,
  xp = 0x0.0004,
- spark = smokespark,
- sparkodds = 4,
+ sparks = smokespark,
+ sparkodds = 3,
 })
 
 function rnd_spawn_loc()
@@ -1695,15 +1695,15 @@ function spark_particle:draw()
 end
 
 function spark(sprs, x, y, dx, dy, odds, fg)
- if (sprs==nil or flr(rnd(odds)) ~= 0) return
+ if (sprs==nil or flr(rnd(odds) or (abs(dx) < 0.5 and abs(dy))) ~= 0) return
  local target = fg and intangibles_fg or intangibles_bg
  target:push_back(spark_particle.new{
   x = x + rnd(4) - 2,
   y = y + rnd(4) - 2,
   sprs = sprs,
   sidx = 1,
-  dx = dx + rnd(2) - 1,
-  dy = dy + rnd(2) - 1,
+  dx = dx * rnd(2),
+  dy = dy * rnd(2),
  })
 end
 -->8