global and local action

The system actions can be sort into two kinds at registers standpoint: global and local.

• the global means all particles of the container will have the same attribute.
  • The global action use a vc or fc as parameters to figure out the action’s result.
  • At each render time,the action will set the vs or fc that it use.In theory,we can change the value at running time.But it may seem strange (jump or inconsecutive) if you change it.So I forbid the changement at running time.
• the local means each particles have their own attributes.
  • The global action use va or v as parameters to figure out the action’s result.Because there is only 8 va and v,we should avoid using it As far as possible.
  • The values of the local is set at the cpu stage,we can’t change it at running time.