Behavior Trees

Behavior trees traditionally use a handful of simple primitives for control flow.

SequenceFlow

Run children in the order they were added and end if one fails. This example will run both children and return RunResult::Success

world.spawn(SequenceFlow)
  .with_children(|parent| {
    parent.spawn(EndOnRun::success());
    parent.spawn(EndOnRun::success());
  })

FallbackFlow

Run children in the order they were added and end if one succeeds. This example will run both children and return RunResult::Success

world.spawn(FallbackFlow)
  .with_children(|parent| {
    parent.spawn(EndOnRun::failure());
    parent.spawn(EndOnRun::success());
  })

ParallelFlow

This example will run both children and return RunResult::Success. Note that if both children return a RunResult this action will bubble both of them to its parent.

world.spawn(ParallelFlow)
  .with_children(|parent| {
    parent.spawn_empty();
    parent.spawn(EndOnRun::success());
  })