CLK/Outputs/DisplayMetrics.hpp

58 lines
1.6 KiB
C++

//
// DisplayMetrics.hpp
// Clock Signal
//
// Created by Thomas Harte on 04/03/2019.
// Copyright © 2019 Thomas Harte. All rights reserved.
//
#pragma once
#include "ScanTarget.hpp"
#include <array>
#include <atomic>
#include <chrono>
namespace Outputs::Display {
/*!
A class to derive various metrics about the input to a ScanTarget,
based purely on empirical observation. In particular it is intended
to allow for host-client frame synchronisation.
*/
class Metrics {
public:
/// Notifies Metrics of a beam event.
void announce_event(ScanTarget::Event event);
/// Notifies Metrics that the size of the output buffer has changed.
void announce_did_resize();
/// Provides Metrics with a new data point for output speed estimation.
void announce_draw_status(size_t lines, std::chrono::high_resolution_clock::duration duration, bool complete);
/// Provides Metrics with a new data point for output speed estimation, albeit without line-specific information.
void announce_draw_status(bool complete);
/// @returns @c true if Metrics thinks a lower output buffer resolution is desirable in the abstract; @c false otherwise.
bool should_lower_resolution() const;
/// @returns An estimate of the number of lines being produced per frame, excluding vertical sync.
float visible_lines_per_frame_estimate() const;
/// @returns The number of lines since vertical retrace ended.
int current_line() const;
private:
int lines_this_frame_ = 0;
std::array<int, 20> line_total_history_;
size_t line_total_history_pointer_ = 0;
void add_line_total(int);
std::atomic<int> frames_hit_ = 0;
std::atomic<int> frames_missed_ = 0;
};
}