Managing Object Ticking Order
How can we ensure that objects are ticked in a specific order to avoid dependency issues?
Managing the order in which objects are ticked is crucial for avoiding dependency issues and ensuring consistent behavior in your game. Here are several strategies to control the ticking order.
Priority-based Ticking
Assign priorities to different types of objects and tick them in order of priority.
#include <algorithm>
#include <memory>
#include <vector>
class GameObject {
public:
virtual void Tick() = 0;
virtual int GetPriority() const = 0;
};
class World {
public:
void AddObject(
std::unique_ptr<GameObject> obj) {
objects.push_back(std::move(obj));
std::sort(objects.begin(), objects.end(),
[](const auto& a, const auto& b){
return a->GetPriority() > b->
GetPriority();
});
}
void TickAll() {
for (const auto& obj : objects) {
obj->Tick();
}
}
private:
std::vector<std::unique_ptr<GameObject>>
objects;
};Multi-phase Ticking
Implement multiple ticking phases for different types of updates.
class GameObject {
public:
virtual void TickPhysics() {}
virtual void TickLogic() {}
virtual void TickRendering() {}
};
class World {
public:
void TickAll() {
for (const auto& obj : objects) {
obj->TickPhysics();
}
for (const auto& obj : objects) {
obj->TickLogic();
}
for (const auto& obj : objects) {
obj->TickRendering();
}
}
// ...
};Dependency Graph
For complex systems, you can create a dependency graph and perform a topological sort to determine the ticking order.
#include <unordered_set>
class GameObject {
public:
virtual void Tick() = 0;
virtual std::vector<GameObject*>
GetDependencies() const { return {}; }
};
class World {
public:
void TickAll() {
std::unordered_set<GameObject*> visited;
std::vector<GameObject*> sortedObjects;
for (const auto& obj : objects) {
DepthFirstSort(obj.get(), visited,
sortedObjects);
}
for (auto it = sortedObjects.rbegin(); it !=
sortedObjects.rend(); ++it) {
(*it)->Tick();
}
}
private:
void DepthFirstSort(
GameObject* obj,
std::unordered_set<GameObject*>& visited,
std::vector<GameObject*>& sorted
) {
if (visited.find(obj) != visited.
end()) return;
visited.insert(obj);
for (auto dep : obj->GetDependencies()) {
DepthFirstSort(dep, visited, sorted);
}
sorted.push_back(obj);
}
std::vector<std::unique_ptr<GameObject>> objects;
};By implementing one or a combination of these strategies, you can ensure that objects are ticked in the correct order, avoiding dependency issues and maintaining consistent game behavior.
Ticking
Using Tick() functions to update game objects independently of events