The Need for Ticking in Game Development

Ticking is a crucial concept in game development that goes beyond event-driven updates. While events are great for handling specific interactions, ticking provides a consistent and predictable way to update game objects, regardless of whether events occur or not.

Here's why ticking is essential:

1. Continuous Updates: Many game objects need to update their state continuously, even when no events are occurring. For example, an enemy AI might need to move or make decisions every frame, or a particle system might need to update particle positions constantly.
2. Time-based Behavior: Ticking allows you to implement time-based behavior easily. You can update object positions, animations, or other properties based on the time elapsed since the last frame.
3. Synchronization: Ticking ensures that all objects are updated in a synchronized manner, maintaining consistency in the game world.
4. Performance Control: With ticking, you have fine-grained control over when and how often updates occur, allowing for better performance optimization.

Here's a simple example demonstrating the difference between event-driven updates and ticking:

1#include <SDL.h>
2
3#include <iostream>
4
5class GameObject {
6public:
7  virtual void HandleEvent(SDL_Event& E) {}
8  virtual void Tick() {}
9};
10
11class Player : public GameObject {
12public:
13  void HandleEvent(SDL_Event& E) override {
14    if (E.type == SDL_KEYDOWN &&
15      E.key.keysym.sym == SDLK_SPACE) {
16      std::cout << "Player jumped!\n";
17    }
18  }
19
20  void Tick() override {
21    // Update player position every frame
22    x += velocity * deltaTime;
23    std::cout << "Player position updated: "
24      << x << "\n";
25  }
26
27private:
28  float x{0};
29  float velocity{1.0f};
30  float deltaTime{0.016f}; // Assuming 60 FPS
31};
32
33int main() {
34  Player player;
35  SDL_Event event;
36
37  // Simulate a few frames
38  for (int i = 0; i < 5; ++i) {
39    // Handle events (only occurs when there's input)
40    while (SDL_PollEvent(&event)) {
41      player.HandleEvent(event);
42    }
43
44    // Tick (occurs every frame)
45    player.Tick();
46  }
47
48  return 0;
49}

1Player position updated: 0.016
2Player position updated: 0.032
3Player position updated: 0.048
4Player position updated: 0.064
5Player position updated: 0.08

In this example, the player's position is updated every frame through ticking, ensuring smooth movement. Event handling only occurs when specific inputs are received.

This combination allows for responsive input handling while maintaining continuous game state updates.