Using Low-Resolution Timers in Games

While high-resolution timers are generally preferred in game development for their precision, there are indeed situations where lower resolution timers might be more appropriate. Let's explore some of these scenarios:

Resource Conservation

Lower resolution timers, like SDL_GetTicks64(), typically consume fewer system resources than high-resolution timers. This can be beneficial in certain situations:

1#include <SDL.h>
2#include <iostream>
3
4void lowResolutionExample() {
5  Uint64 start{SDL_GetTicks64()};
6
7  // Simulate work
8  SDL_Delay(100);
9
10  Uint64 end{SDL_GetTicks64()};
11  std::cout << "Time elapsed: "
12    << (end - start);
13}
14
15int main(int argc, char** argv) {
16  SDL_Init(SDL_INIT_TIMER);
17  lowResolutionExample();
18  SDL_Quit();
19  return 0;
20}

1Time elapsed: 100ms

This approach is less taxing on the CPU, which can be crucial for:

1. Mobile devices where battery life is a concern.
2. Games with low performance requirements that don't need high precision.
3. Background processes or less critical game systems.

Simplified Logic

For game mechanics that don't require high precision, using lower resolution timers can simplify your code:

1#include <SDL.h>
2#include <iostream>
3
4class PowerUp {
5  Uint64 spawnTime;
6  const Uint64 duration{10000}; // 10 seconds
7
8public:
9  PowerUp() : spawnTime{SDL_GetTicks64()} {}
10
11  bool isActive() {
12    return (SDL_GetTicks64() - spawnTime) <
13      duration;
14  }
15};
16
17int main(int argc, char** argv) {
18  SDL_Init(SDL_INIT_TIMER);
19
20  PowerUp powerUp;
21  std::cout << "Power-up active: " <<
22    std::boolalpha << powerUp.isActive()
23    << '\n';
24
25  SDL_Delay(11000); // Wait 11 seconds
26  std::cout << "Power-up active: "
27    << powerUp.isActive() << '\n';
28
29  SDL_Quit();
30  return 0;
31}

1Power-up active: true
2Power-up active: false

This example uses SDL_GetTicks64() for a power-up duration. Millisecond precision is more than adequate for this purpose, and the code is straightforward.

Compatibility and Legacy Systems

Some older systems or APIs might not support high-resolution timers. In these cases, using lower resolution timers ensures broader compatibility:

1#include <SDL.h>
2#include <iostream>
3
4void compatibleTimingFunction() {
5#if SDL_VERSION_ATLEAST(2, 0, 18)
6  Uint64 ticks{SDL_GetTicks64()};
7#else
8  Uint32 ticks{SDL_GetTicks()};
9#endif
10  std::cout << "Ticks: " << ticks << '\n';
11}
12
13int main(int argc, char** argv) {
14  SDL_Init(SDL_INIT_TIMER);
15  compatibleTimingFunction();
16  SDL_Quit();
17  return 0;
18}

Network Synchronization

In networked games, the latency of network communications often makes high-resolution timers unnecessary. Using lower resolution timers can simplify network code:

1#include <SDL.h>
2#include <iostream>
3
4struct NetworkPacket {
5  Uint32 timestamp;
6  // Other packet data...
7};
8
9NetworkPacket createPacket() {
10  NetworkPacket packet;
11  // 32-bit timestamp is often sufficient
12  packet.timestamp = SDL_GetTicks();
13  return packet;
14}
15
16int main(int argc, char** argv) {
17  SDL_Init(SDL_INIT_TIMER);
18
19  NetworkPacket packet = createPacket();
20  std::cout << "Packet timestamp: "
21    << packet.timestamp << "ms\n";
22
23  SDL_Quit();
24  return 0;
25}

1Packet timestamp: 0ms

Reduced Precision Requirements

Some game systems don't require high precision. For example, a day/night cycle in a game might work perfectly well with second-level precision:

1#include <SDL.h>
2#include <iostream>
3
4class DayNightCycle {
5  Uint64 cycleStartTime;
6  // 5 minutes (300,000 ms)
7  const Uint64 cycleDuration{300000};
8
9public:
10  DayNightCycle() : cycleStartTime{
11    SDL_GetTicks64()} {}
12
13  float getDayProgress() {
14    Uint64 elapsedTime{
15      (SDL_GetTicks64() - cycleStartTime) %
16      cycleDuration};
17
18    return static_cast<float>(elapsedTime) /
19      cycleDuration;
20  }
21};
22
23int main(int argc, char** argv) {
24  SDL_Init(SDL_INIT_TIMER);
25
26  DayNightCycle cycle;
27  std::cout << "Day progress: "
28    << cycle.getDayProgress();
29
30  SDL_Delay(150000); // Wait 2.5 minutes
31  std::cout << "\nDay progress: "
32    << cycle.getDayProgress();
33
34  SDL_Quit();
35  return 0;
36}

1Day progress: 0
2Day progress: 0.5

In this case, millisecond precision from SDL_GetTicks64() is more than adequate, and using a higher resolution timer wouldn't provide any noticeable benefit.

While high-resolution timers are crucial for many aspects of game development, it's important to choose the right tool for each job. By using lower resolution timers where appropriate, you can often simplify your code, improve performance, and ensure broader compatibility without sacrificing necessary precision.