2023-01-05 20:25:55 +08:00
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/**************************************************************************/
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/* main_timer_sync.h */
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/**************************************************************************/
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/* This file is part of: */
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/* GODOT ENGINE */
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/* https://godotengine.org */
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/**************************************************************************/
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/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
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/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
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/* */
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/* Permission is hereby granted, free of charge, to any person obtaining */
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/* a copy of this software and associated documentation files (the */
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/* "Software"), to deal in the Software without restriction, including */
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/* without limitation the rights to use, copy, modify, merge, publish, */
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/* distribute, sublicense, and/or sell copies of the Software, and to */
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/* permit persons to whom the Software is furnished to do so, subject to */
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/* the following conditions: */
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/* */
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/* The above copyright notice and this permission notice shall be */
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/* included in all copies or substantial portions of the Software. */
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/* */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
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/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
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/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
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/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
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/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
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/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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/**************************************************************************/
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2018-05-17 01:19:33 +08:00
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2019-02-12 21:23:35 +08:00
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#ifndef MAIN_TIMER_SYNC_H
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#define MAIN_TIMER_SYNC_H
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2018-05-16 04:12:35 +08:00
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2020-11-08 06:33:38 +08:00
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#include "core/config/engine.h"
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2018-05-16 04:12:35 +08:00
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2021-09-01 22:47:12 +08:00
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// Uncomment this define to get more debugging logs for the delta smoothing.
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// #define GODOT_DEBUG_DELTA_SMOOTHER
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2018-05-16 04:12:35 +08:00
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struct MainFrameTime {
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2021-05-21 13:23:35 +08:00
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double process_step; // delta time to advance during process()
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2018-05-16 04:12:35 +08:00
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int physics_steps; // number of times to iterate the physics engine
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2021-05-21 13:23:35 +08:00
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double interpolation_fraction; // fraction through the current physics tick
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2018-05-16 04:12:35 +08:00
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2021-05-21 13:23:35 +08:00
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void clamp_process_step(double min_process_step, double max_process_step);
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2018-05-16 04:12:35 +08:00
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};
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class MainTimerSync {
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2021-09-01 22:47:12 +08:00
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class DeltaSmoother {
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public:
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// pass the recorded delta, returns a smoothed delta
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int64_t smooth_delta(int64_t p_delta);
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private:
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void update_refresh_rate_estimator(int64_t p_delta);
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bool fps_allows_smoothing(int64_t p_delta);
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// estimated vsync delta (monitor refresh rate)
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int64_t _vsync_delta = 16666;
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// keep track of accumulated time so we know how many vsyncs to advance by
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int64_t _leftover_time = 0;
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// keep a rough measurement of the FPS as we run.
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// If this drifts a long way below or above the refresh rate, the machine
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// is struggling to keep up, and we can switch off smoothing. This
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// also deals with the case that the user has overridden the vsync in the GPU settings,
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// in which case we don't want to try smoothing.
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static const int MEASURE_FPS_OVER_NUM_FRAMES = 64;
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int64_t _measurement_time = 0;
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int64_t _measurement_frame_count = 0;
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int64_t _measurement_end_frame = MEASURE_FPS_OVER_NUM_FRAMES;
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int64_t _measurement_start_time = 0;
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bool _measurement_allows_smoothing = true;
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// we can estimate the fps by growing it on condition
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// that a large proportion of frames are higher than the current estimate.
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int32_t _estimated_fps = 0;
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int32_t _hits_at_estimated = 0;
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int32_t _hits_above_estimated = 0;
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int32_t _hits_below_estimated = 0;
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int32_t _hits_one_above_estimated = 0;
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int32_t _hits_one_below_estimated = 0;
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bool _estimate_complete = false;
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bool _estimate_locked = false;
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// data for averaging the delta over a second or so
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// to prevent spurious values
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int64_t _estimator_total_delta = 0;
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int32_t _estimator_delta_readings = 0;
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void made_new_estimate() {
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_hits_above_estimated = 0;
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_hits_at_estimated = 0;
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_hits_below_estimated = 0;
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_hits_one_above_estimated = 0;
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_hits_one_below_estimated = 0;
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_estimate_complete = false;
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#ifdef GODOT_DEBUG_DELTA_SMOOTHER
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print_line("estimated fps " + itos(_estimated_fps));
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#endif
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}
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} _delta_smoother;
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2018-05-16 04:12:35 +08:00
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// wall clock time measured on the main thread
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2020-05-12 23:01:17 +08:00
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uint64_t last_cpu_ticks_usec = 0;
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uint64_t current_cpu_ticks_usec = 0;
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2018-05-16 04:12:35 +08:00
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// logical game time since last physics timestep
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2021-05-21 13:23:35 +08:00
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double time_accum = 0;
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2018-05-16 04:12:35 +08:00
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2020-12-22 17:50:29 +08:00
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// current difference between wall clock time and reported sum of process_steps
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2021-05-21 13:23:35 +08:00
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double time_deficit = 0;
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2018-05-16 04:12:35 +08:00
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// number of frames back for keeping accumulated physics steps roughly constant.
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// value of 12 chosen because that is what is required to make 144 Hz monitors
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// behave well with 60 Hz physics updates. The only worse commonly available refresh
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// would be 85, requiring CONTROL_STEPS = 17.
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static const int CONTROL_STEPS = 12;
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// sum of physics steps done over the last (i+1) frames
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int accumulated_physics_steps[CONTROL_STEPS];
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// typical value for accumulated_physics_steps[i] is either this or this plus one
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int typical_physics_steps[CONTROL_STEPS];
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2020-05-12 23:01:17 +08:00
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int fixed_fps = 0;
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2018-05-16 04:12:35 +08:00
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protected:
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2020-12-22 17:50:29 +08:00
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// returns the fraction of p_physics_step required for the timer to overshoot
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2018-05-16 04:12:35 +08:00
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// before advance_core considers changing the physics_steps return from
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// the typical values as defined by typical_physics_steps
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2021-05-21 13:23:35 +08:00
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double get_physics_jitter_fix();
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2018-05-16 04:12:35 +08:00
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// gets our best bet for the average number of physics steps per render frame
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// return value: number of frames back this data is consistent
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2021-05-21 13:23:35 +08:00
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int get_average_physics_steps(double &p_min, double &p_max);
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2018-05-16 04:12:35 +08:00
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2020-12-22 17:50:29 +08:00
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// advance physics clock by p_process_step, return appropriate number of steps to simulate
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2021-08-11 08:35:16 +08:00
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MainFrameTime advance_core(double p_physics_step, int p_physics_ticks_per_second, double p_process_step);
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2018-05-16 04:12:35 +08:00
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// calls advance_core, keeps track of deficit it adds to animaption_step, make sure the deficit sum stays close to zero
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2021-08-11 08:35:16 +08:00
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MainFrameTime advance_checked(double p_physics_step, int p_physics_ticks_per_second, double p_process_step);
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2018-05-16 04:12:35 +08:00
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// determine wall clock step since last iteration
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2021-05-21 13:23:35 +08:00
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double get_cpu_process_step();
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2018-05-16 04:12:35 +08:00
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public:
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MainTimerSync();
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// start the clock
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void init(uint64_t p_cpu_ticks_usec);
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// set measured wall clock time
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void set_cpu_ticks_usec(uint64_t p_cpu_ticks_usec);
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//set fixed fps
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void set_fixed_fps(int p_fixed_fps);
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// advance one frame, return timesteps to take
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2021-08-11 08:35:16 +08:00
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MainFrameTime advance(double p_physics_step, int p_physics_ticks_per_second);
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2018-05-16 04:12:35 +08:00
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};
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2019-02-12 21:23:35 +08:00
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#endif // MAIN_TIMER_SYNC_H
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