snes9x/vulkan/std_chrono_throttle.cpp
BearOso 309f9e650d vulkan: Move throttle out of swapchain.
Make the swapchain wrapper more flexible, allowing deferring the
swap from the end_frame function.
2023-03-07 14:01:29 -06:00

52 lines
1.0 KiB
C++

#include "std_chrono_throttle.hpp"
#include <thread>
using namespace std::chrono;
void Throttle::set_frame_rate(double frame_rate)
{
max_frame_rate = frame_rate;
frame_duration = 1.0 / max_frame_rate;
frame_duration_us = microseconds(int64_t(frame_duration * 1000000.0));
}
microseconds Throttle::remaining()
{
auto now = time_point_cast<microseconds>(steady_clock::now());
auto diff = (now - then);
return frame_duration_us - diff;
}
void Throttle::wait_for_frame()
{
auto time_to_wait = remaining();
if (time_to_wait.count() > 0)
std::this_thread::sleep_for(time_to_wait);
}
void Throttle::wait_for_frame_and_rebase_time()
{
auto time_to_wait = remaining();
if (time_to_wait < -frame_duration_us / 10)
reset();
if (time_to_wait.count() > 0)
{
std::this_thread::sleep_for(time_to_wait);
advance();
}
}
void Throttle::advance()
{
then += frame_duration_us;
}
void Throttle::reset()
{
auto now = time_point_cast<microseconds>(steady_clock::now());
then = now;
}