Designing Games with Game Maker - YoYo Games

front of, or between object instances, each particle system has a depth, similar to instances
and tiles.
Particle systems will live on forever after they are created. So even if you change room or
restart the game, the systems and the particles remain. So you better make sure you destroy
them once you no longer need them.
The following basic functions deal with particle systems:
part_system_create() Creates a new particle system. It returns the index
of the system. This index must be used in all calls below to set the properties
of the particle system.
part_system_destroy(ind) Destroys the particle system ind. Call this if
you don't need it anymore to save space.
part_system_exists(ind) Returns whether the indicated particle system
exists.
part_system_clear(ind) Clears the particle system ind to its default
settings, removing all particles and emitter and attractors in it.
part_system_draw_order(ind,oldtonew) Sets the order in which the
particle system draws the particles. When oldtonew is true the oldest particles
are drawn first and the newer one lie on top of them (default). Otherwise the
newest particles are drawn first. This can give rather different effects.
part_system_depth(ind,depth) Sets the depth of the particle system.
This can be used to let the particles appear behind, in front of, or in between
instances.
part_system_position(ind,x,y) Sets the position where the particle
system is drawn. This is normally not necessary but if you want to have
particles at a position relative to a moving object, you can set the position e.g.
to that object.
As indicated above, the particle system is automatically updated and drawn. But sometimes
this is not what you want. To facilitate this, you can switch off automatic updating or drawing
and then decide yourself when to update or draw the particle system. For this you can use the
following functions:
part_system_automatic_update(ind,automatic) Indicates whether
the particle system must be updated automatically (1) or not (0). Default is 1.