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Improve accuracy of frame rate limiter

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This commit is contained in:
Benau 2022-11-09 14:06:31 +08:00
parent 4c7353a3a4
commit 4e8744f047
2 changed files with 118 additions and 141 deletions
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118
src/main_loop.cpp
View File

@ -58,6 +58,8 @@
#include "utils/translation.hpp"
#include "io/rich_presence.hpp"
#include <thread>
#ifndef WIN32
#include <unistd.h>
#endif
@ -98,8 +100,8 @@ MainLoop::MainLoop(unsigned parent_pid, bool download_assets)
: m_abort(false), m_request_abort(false), m_paused(false),
m_ticks_adjustment(0), m_parent_pid(parent_pid)
{
m_curr_time = 0;
m_prev_time = 0;
m_curr_time = std::chrono::steady_clock::now();
m_prev_time = std::chrono::steady_clock::now();
m_throttle_fps = true;
m_allow_large_dt = false;
m_frame_before_loading_world = false;
@ -188,7 +190,7 @@ extern "C" void reset_network_body()
* too low (the frame rate too high), the process will sleep to reach the
* maximum frame rate.
*/
float MainLoop::getLimitedDt()
double MainLoop::getLimitedDt()
{
m_prev_time = m_curr_time;
@ -215,7 +217,6 @@ float MainLoop::getLimitedDt()
resume_mainloop();
}
#endif
float dt = 0;
// In profile mode without graphics, run with a fixed dt of 1/60
if ((ProfileWorld::isProfileMode() && GUIEngine::isNoGraphics()) ||
@ -224,9 +225,7 @@ float MainLoop::getLimitedDt()
return 1.0f/60.0f;
}
while( 1 )
{
m_curr_time = StkTime::getMonoTimeMs();
m_curr_time = std::chrono::steady_clock::now();
if (m_prev_time > m_curr_time)
{
m_prev_time = m_curr_time;
@ -252,7 +251,7 @@ float MainLoop::getLimitedDt()
}
}
}
dt = (float)(m_curr_time - m_prev_time);
double dt = convertToTime(m_curr_time, m_prev_time);
// On a server (i.e. without graphics) the frame rate can be under
// 1 ms, i.e. dt = 0. Additionally, the resolution of a sleep
// statement is not that precise either: if the sleep statement
@ -265,13 +264,13 @@ float MainLoop::getLimitedDt()
while (dt == 0)
{
StkTime::sleep(1);
m_curr_time = StkTime::getMonoTimeMs();
m_curr_time = std::chrono::steady_clock::now();
if (m_prev_time > m_curr_time)
{
Log::error("MainLopp", "System clock keeps backwards!");
m_prev_time = m_curr_time;
}
dt = (float)(m_curr_time - m_prev_time);
dt = convertToTime(m_curr_time, m_prev_time);
}
const World* const world = World::getWorld();
@ -301,41 +300,11 @@ float MainLoop::getLimitedDt()
!m_allow_large_dt)
{
/* time 3 internal substeps take */
const float MAX_ELAPSED_TIME = 3.0f*1.0f / 60.0f*1000.0f;
const double MAX_ELAPSED_TIME = 3.0f*1.0f / 60.0f*1000.0f;
if (dt > MAX_ELAPSED_TIME) dt = MAX_ELAPSED_TIME;
}
if (!m_throttle_fps || ProfileWorld::isProfileMode()) break;
// Throttle fps if more than maximum, which can reduce
// the noise the fan on a graphics card makes.
// When in menus, reduce FPS much, it's not necessary to push to the
// maximum for plain menus
#ifdef IOS_STK
// For iOS devices most at locked at 60, for new iPad Pro supports 120
// which is currently m_max_fps
const int max_fps =
UserConfigParams::m_swap_interval == 2 ? UserConfigParams::m_max_fps :
UserConfigParams::m_swap_interval == 1 ? 60 :
30;
#else
const int max_fps = (irr_driver->isRecording() &&
UserConfigParams::m_limit_game_fps )
? UserConfigParams::m_record_fps
: UserConfigParams::m_max_fps;
#endif
const int current_fps = (int)(1000.0f / dt);
if (!m_throttle_fps || current_fps <= max_fps ||
ProfileWorld::isProfileMode() ) break;
int wait_time = 1000 / max_fps - 1000 / current_fps;
if (wait_time < 1) wait_time = 1;
PROFILER_PUSH_CPU_MARKER("Throttle framerate", 0, 0, 0);
StkTime::sleep(wait_time);
PROFILER_POP_CPU_MARKER();
} // while(1)
dt *= 0.001f;
dt *= 0.001;
return dt;
} // getLimitedDt
@ -427,10 +396,10 @@ void MainLoop::updateRace(int ticks, bool fast_forward)
*/
void MainLoop::run()
{
m_curr_time = StkTime::getMonoTimeMs();
m_curr_time = std::chrono::steady_clock::now();
// DT keeps track of the leftover time, since the race update
// happens in fixed timesteps
float left_over_time = 0;
double left_over_time = 0;
#ifdef WIN32
HANDLE parent = 0;
@ -483,6 +452,7 @@ void MainLoop::run()
#endif
PROFILER_PUSH_CPU_MARKER("Main loop", 0xFF, 0x00, 0xF7);
TimePoint frame_start = std::chrono::steady_clock::now();
left_over_time += getLimitedDt();
int num_steps = stk_config->time2Ticks(left_over_time);
@ -676,8 +646,8 @@ void MainLoop::run()
// in CutsceneWorld::enterRaceOverState
// Reset the timer for correct time for cutscene
m_frame_before_loading_world = false;
m_curr_time = StkTime::getMonoTimeMs();
left_over_time = 0.0f;
m_curr_time = std::chrono::steady_clock::now();
left_over_time = 0.0;
break;
}
@ -708,8 +678,8 @@ void MainLoop::run()
{
// irr_driver->getDevice()->run() loads the world
m_frame_before_loading_world = false;
m_curr_time = StkTime::getMonoTimeMs();
left_over_time = 0.0f;
m_curr_time = std::chrono::steady_clock::now();
left_over_time = 0.0;
}
if (abort)
@ -725,6 +695,31 @@ void MainLoop::run()
gp->sendActions();
}
}
TimePoint frame_end = std::chrono::steady_clock::now();
double frame_time = convertToTime(frame_end, frame_start) * 0.001;
const double current_fps = 1.0 / frame_time;
const double max_fps =
(irr_driver->isRecording() && UserConfigParams::m_limit_game_fps) ?
UserConfigParams::m_record_fps : UserConfigParams::m_max_fps;
// Throttle fps if more than maximum, which can reduce
// the noise the fan on a graphics card makes.
// No need to throttle if vsync is on (m_swap_interval == 1) as
// endScene handles fps according to monitor refresh rate
if ((UserConfigParams::m_swap_interval == 0 ||
GUIEngine::isNoGraphics()) &&
m_throttle_fps && !ProfileWorld::isProfileMode() &&
current_fps > max_fps)
{
double wait_time = 1.0 / max_fps - 1.0 / current_fps;
std::chrono::nanoseconds wait_time_ns(
(uint64_t)(wait_time * 1000.0 * 1000.0 * 1000.0));
PROFILER_PUSH_CPU_MARKER("Throttle framerate", 0, 0, 0);
std::this_thread::sleep_for(wait_time_ns);
PROFILER_POP_CPU_MARKER();
}
PROFILER_POP_CPU_MARKER(); // MainLoop pop
PROFILER_SYNC_FRAME();
} // while !m_abort
@ -761,33 +756,6 @@ void MainLoop::renderGUI(int phase, int loop_index, int loop_size)
irr_driver->getDevice()->setEventReceiver(NULL);
irr_driver->getDevice()->run();
irr_driver->getDevice()->setEventReceiver(GUIEngine::EventHandler::get());
return;
// Rendering past phase 7000 causes the minimap to not work
// on higher graphical settings
if (phase > 7000)
{
m_request_abort = !irr_driver->getDevice()->run();
return;
}
uint64_t now = StkTime::getMonoTimeMs();
float dt = (now - m_curr_time)/1000.0f;
if (dt < 1.0 / 30.0f) return;
m_curr_time = now;
// TODO: remove debug output
//Log::verbose("mainloop", "Rendergui t %llu dt %f phase %d index %d / %d",
// now, dt, phase, loop_index, loop_size);
irr_driver->update(dt, /*is_loading*/true);
GUIEngine::update(dt);
m_request_abort = !irr_driver->getDevice()->run();
//TODO: remove debug output
// uint64_t now2 = StkTime::getMonoTimeMs();
// Log::verbose("mainloop", " duration t %llu dt %llu", now, now2-now);
#endif
} // renderGUI
/* EOF */

15
src/main_loop.hpp
View File

@ -23,12 +23,14 @@
#include "utils/synchronised.hpp"
#include "utils/types.hpp"
#include <atomic>
#include <chrono>
/** Management class for the whole gameflow, this is where the
main-loop is */
class MainLoop
{
private:
using TimePoint = std::chrono::steady_clock::time_point;
/** True if the main loop should exit. */
std::atomic_bool m_abort;
@ -48,11 +50,18 @@ private:
Synchronised<int> m_ticks_adjustment;
uint64_t m_curr_time;
uint64_t m_prev_time;
TimePoint m_curr_time;
TimePoint m_prev_time;
unsigned m_parent_pid;
float getLimitedDt();
double getLimitedDt();
void updateRace(int ticks, bool fast_forward);
double convertToTime(const TimePoint& cur, const TimePoint& prev) const
{
auto duration = cur - prev;
auto value =
std::chrono::duration_cast<std::chrono::nanoseconds>(duration);
return value.count() / (1000.0 * 1000.0);
}
public:
MainLoop(unsigned parent_pid, bool download_assets = false);
~MainLoop();