A C++ behavior tree header-only library.
- behavior tree
- predefined composites
- predefined decorators
- rudimentary blackboard
Include bt.hpp and bt folder in your project.
#include <bt.hpp>
class WaitNode : public bt::Leaf
{
public:
// note: using a blackboard is optional
WaitNode(bt::Blackboard::Ptr board, int limit) : Leaf(board), limit(limit) {}
void Initialize() override
{
counter = 0;
}
Status Update() override
{
counter++;
if (counter >= limit) {
return Node::Status::Success;
}
return Node::Status::Running;
}
private:
int limit;
int counter;
};
int main()
{
bt::BehaviorTree tree;
// each tree has one blackboard each, which the leafs can use
auto &blackboard = tree.GetBlackBoard();
// create a sequence
auto attackEnemySequence = std::make_shared<bt::Sequence>();
auto targetNearestEnemyNode = std::make_shared<TargetNearestEnemyNode>(blackboard);
auto moveToEnemyNode = std::make_shared<MoveToEnemyNode>(blackboard);
auto attackEnemyNode = std::make_shared<AttackEnemyNode>(blackboard);
attackEnemySequence->AddChild(targetNearestEnemyNode);
attackEnemySequence->AddChild(moveToEnemyNode);
attackEnemySequence->AddChild(attackEnemyNode);
// ...
// create a selector
auto selector = std::make_shared<bt::Selector>();
selector->AddChild(attackEnemySequence);
selector->AddChild(idleSequence);
// set the root of the tree
tree.SetRoot(selector);
// inside game loop
tree.Update();
return 0;
}MIT (c) arvidsson