Feature: Framerate display window (#6822)

Frame rate and various game loop/graphics timing measurements and graphs. Accessible via the Help menu, and can print some stats in the console via the fps command.

1 files changed, 837 insertions, 0 deletions

diff --git a/src/framerate_gui.cpp b/src/framerate_gui.cpp
new file mode 100644
index 000000000..0d6cc55c5
--- /dev/null
+++ b/src/framerate_gui.cpp
@@ -0,0 +1,837 @@
+/* $Id$ */
+
+/*
+* This file is part of OpenTTD.
+* OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
+* OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+* See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/** @file framerate_gui.cpp GUI for displaying framerate/game speed information. */
+
+#include "framerate_type.h"
+#include <chrono>
+#include "gfx_func.h"
+#include "window_gui.h"
+#include "table/sprites.h"
+#include "strings_func.h"
+#include "debug.h"
+#include "console_func.h"
+#include "console_type.h"
+
+
+namespace {
+
+	/** Number of data points to keep in buffer for each performance measurement */
+	const int NUM_FRAMERATE_POINTS = 512;
+	/** Units a second is divided into in performance measurements */
+	const TimingMeasurement TIMESTAMP_PRECISION = 1000000;
+
+	struct PerformanceData {
+		/** Duration value indicating the value is not valid should be considered a gap in measurements */
+		static const TimingMeasurement INVALID_DURATION = UINT64_MAX;
+
+		/** Time spent processing each cycle of the performance element, circular buffer */
+		TimingMeasurement durations[NUM_FRAMERATE_POINTS];
+		/** Start time of each cycle of the performance element, circular buffer */
+		TimingMeasurement timestamps[NUM_FRAMERATE_POINTS];
+		/** Expected number of cycles per second when the system is running without slowdowns */
+		double expected_rate;
+		/** Next index to write to in \c durations and \c timestamps */
+		int next_index;
+		/** Last index written to in \c durations and \c timestamps */
+		int prev_index;
+		/** Number of data points recorded, clamped to \c NUM_FRAMERATE_POINTS */
+		int num_valid;
+
+		/** Current accumulated duration */
+		TimingMeasurement acc_duration;
+		/** Start time for current accumulation cycle */
+		TimingMeasurement acc_timestamp;
+
+		explicit PerformanceData(double expected_rate) : expected_rate(expected_rate), next_index(0), prev_index(0), num_valid(0) { }
+
+		void Add(TimingMeasurement start_time, TimingMeasurement end_time)
+		{
+			this->durations[this->next_index] = end_time - start_time;
+			this->timestamps[this->next_index] = start_time;
+			this->prev_index = this->next_index;
+			this->next_index += 1;
+			if (this->next_index >= NUM_FRAMERATE_POINTS) this->next_index = 0;
+			this->num_valid = min(NUM_FRAMERATE_POINTS, this->num_valid + 1);
+		}
+
+		void BeginAccumulate(TimingMeasurement start_time)
+		{
+			this->timestamps[this->next_index] = this->acc_timestamp;
+			this->durations[this->next_index] = this->acc_duration;
+			this->prev_index = this->next_index;
+			this->next_index += 1;
+			if (this->next_index >= NUM_FRAMERATE_POINTS) this->next_index = 0;
+			this->num_valid = min(NUM_FRAMERATE_POINTS, this->num_valid + 1);
+
+			this->acc_duration = 0;
+			this->acc_timestamp = start_time;
+		}
+
+		void AddAccumulate(TimingMeasurement duration)
+		{
+			this->acc_duration += duration;
+		}
+
+		void AddPause(TimingMeasurement start_time)
+		{
+			if (this->durations[this->prev_index] != INVALID_DURATION) {
+				this->timestamps[this->next_index] = start_time;
+				this->durations[this->next_index] = INVALID_DURATION;
+				this->prev_index = this->next_index;
+				this->next_index += 1;
+				if (this->next_index >= NUM_FRAMERATE_POINTS) this->next_index = 0;
+				this->num_valid += 1;
+			}
+		}
+
+		/** Get average cycle processing time over a number of data points */
+		double GetAverageDurationMilliseconds(int count)
+		{
+			count = min(count, this->num_valid);
+
+			int first_point = this->prev_index - count;
+			if (first_point < 0) first_point += NUM_FRAMERATE_POINTS;
+
+			/* Sum durations, skipping invalid points */
+			double sumtime = 0;
+			for (int i = first_point; i < first_point + count; i++) {
+				auto d = this->durations[i % NUM_FRAMERATE_POINTS];
+				if (d != INVALID_DURATION) {
+					sumtime += d;
+				} else {
+					/* Don't count the invalid durations */
+					count--;
+				}
+			}
+
+			if (count == 0) return 0; // avoid div by zero
+			return sumtime * 1000 / count / TIMESTAMP_PRECISION;
+		}
+
+		/** Get current rate of a performance element, based on approximately the past one second of data */
+		double GetRate()
+		{
+			/* Start at last recorded point, end at latest when reaching the earliest recorded point */
+			int point = this->prev_index;
+			int last_point = this->next_index - this->num_valid;
+			if (last_point < 0) last_point += NUM_FRAMERATE_POINTS;
+
+			/** Number of data points collected */
+			int count = 0;
+			/** Time of previous data point */
+			TimingMeasurement last = this->timestamps[point];
+			/** Total duration covered by collected points */
+			TimingMeasurement total = 0;
+
+			while (point != last_point) {
+				/* Only record valid data points, but pretend the gaps in measurements aren't there */
+				if (this->durations[point] != INVALID_DURATION) {
+					total += last - this->timestamps[point];
+					count++;
+				}
+				last = this->timestamps[point];
+				if (total >= TIMESTAMP_PRECISION) break; // end after 1 second has been collected
+				point--;
+				if (point < 0) point = NUM_FRAMERATE_POINTS - 1;
+			}
+
+			if (total == 0 || count == 0) return 0;
+			return (double)count * TIMESTAMP_PRECISION / total;
+		}
+	};
+
+	/** Game loop rate, cycles per second */
+	static const double GL_RATE = 1000.0 / MILLISECONDS_PER_TICK;
+
+	PerformanceData _pf_data[PFE_MAX] = {
+		PerformanceData(GL_RATE),               // PFE_GAMELOOP
+		PerformanceData(1),                     // PFE_ACC_GL_ECONOMY
+		PerformanceData(1),                     // PFE_ACC_GL_TRAINS
+		PerformanceData(1),                     // PFE_ACC_GL_ROADVEHS
+		PerformanceData(1),                     // PFE_ACC_GL_SHIPS
+		PerformanceData(1),                     // PFE_ACC_GL_AIRCRAFT
+		PerformanceData(1),                     // PFE_GL_LANDSCAPE
+		PerformanceData(1),                     // PFE_GL_LINKGRAPH
+		PerformanceData(GL_RATE),               // PFE_DRAWING
+		PerformanceData(1),                     // PFE_ACC_DRAWWORLD
+		PerformanceData(60.0),                  // PFE_VIDEO
+		PerformanceData(1000.0 * 8192 / 44100), // PFE_SOUND
+	};
+
+}
+
+
+/**
+ * Return a timestamp with \c TIMESTAMP_PRECISION ticks per second precision.
+ * The basis of the timestamp is implementation defined, but the value should be steady,
+ * so differences can be taken to reliably measure intervals.
+ */
+static TimingMeasurement GetPerformanceTimer()
+{
+	using namespace std::chrono;
+	return (TimingMeasurement)time_point_cast<microseconds>(high_resolution_clock::now()).time_since_epoch().count();
+}
+
+
+/** Begin a cycle of a measured element. */
+PerformanceMeasurer::PerformanceMeasurer(PerformanceElement elem)
+{
+	assert(elem < PFE_MAX);
+
+	this->elem = elem;
+	this->start_time = GetPerformanceTimer();
+}
+
+/** Finish a cycle of a measured element and store the measurement taken. */
+PerformanceMeasurer::~PerformanceMeasurer()
+{
+	_pf_data[this->elem].Add(this->start_time, GetPerformanceTimer());
+}
+
+/** Set the rate of expected cycles per second of a performance element. */
+void PerformanceMeasurer::SetExpectedRate(double rate)
+{
+	_pf_data[this->elem].expected_rate = rate;
+}
+
+/** Indicate that a cycle of "pause" where no processing occurs. */
+void PerformanceMeasurer::Paused(PerformanceElement elem)
+{
+	_pf_data[elem].AddPause(GetPerformanceTimer());
+}
+
+
+/** Begin measuring one block of the accumulating value. */
+PerformanceAccumulator::PerformanceAccumulator(PerformanceElement elem)
+{
+	assert(elem < PFE_MAX);
+
+	this->elem = elem;
+	this->start_time = GetPerformanceTimer();
+}
+
+/** Finish and add one block of the accumulating value. */
+PerformanceAccumulator::~PerformanceAccumulator()
+{
+	_pf_data[this->elem].AddAccumulate(GetPerformanceTimer() - this->start_time);
+}
+
+/** Store the previous accumulator value and reset for a new cycle of accumulating measurements. */
+void PerformanceAccumulator::Reset(PerformanceElement elem)
+{
+	_pf_data[elem].BeginAccumulate(GetPerformanceTimer());
+}
+
+
+void ShowFrametimeGraphWindow(PerformanceElement elem);
+
+
+enum FramerateWindowWidgets {
+	WID_FRW_CAPTION,
+	WID_FRW_RATE_GAMELOOP,
+	WID_FRW_RATE_DRAWING,
+	WID_FRW_RATE_FACTOR,
+	WID_FRW_INFO_DATA_POINTS,
+	WID_FRW_TIMES_NAMES,
+	WID_FRW_TIMES_CURRENT,
+	WID_FRW_TIMES_AVERAGE,
+};
+
+static const NWidgetPart _framerate_window_widgets[] = {
+	NWidget(NWID_HORIZONTAL),
+		NWidget(WWT_CLOSEBOX, COLOUR_GREY),
+		NWidget(WWT_CAPTION, COLOUR_GREY, WID_FRW_CAPTION), SetDataTip(STR_FRAMERATE_CAPTION, STR_TOOLTIP_WINDOW_TITLE_DRAG_THIS),
+		NWidget(WWT_SHADEBOX, COLOUR_GREY),
+		NWidget(WWT_STICKYBOX, COLOUR_GREY),
+	EndContainer(),
+	NWidget(WWT_PANEL, COLOUR_GREY),
+		NWidget(NWID_VERTICAL), SetPadding(6), SetPIP(0, 3, 0),
+			NWidget(WWT_TEXT, COLOUR_GREY, WID_FRW_RATE_GAMELOOP), SetDataTip(STR_FRAMERATE_RATE_GAMELOOP, STR_FRAMERATE_RATE_GAMELOOP_TOOLTIP),
+			NWidget(WWT_TEXT, COLOUR_GREY, WID_FRW_RATE_DRAWING),  SetDataTip(STR_FRAMERATE_RATE_BLITTER,  STR_FRAMERATE_RATE_BLITTER_TOOLTIP),
+			NWidget(WWT_TEXT, COLOUR_GREY, WID_FRW_RATE_FACTOR),   SetDataTip(STR_FRAMERATE_SPEED_FACTOR,  STR_FRAMERATE_SPEED_FACTOR_TOOLTIP),
+		EndContainer(),
+	EndContainer(),
+	NWidget(WWT_PANEL, COLOUR_GREY),
+		NWidget(NWID_VERTICAL), SetPadding(6), SetPIP(0, 3, 0),
+			NWidget(NWID_HORIZONTAL), SetPIP(0, 6, 0),
+				NWidget(WWT_EMPTY, COLOUR_GREY, WID_FRW_TIMES_NAMES),
+				NWidget(WWT_EMPTY, COLOUR_GREY, WID_FRW_TIMES_CURRENT),
+				NWidget(WWT_EMPTY, COLOUR_GREY, WID_FRW_TIMES_AVERAGE),
+			EndContainer(),
+			NWidget(WWT_TEXT, COLOUR_GREY, WID_FRW_INFO_DATA_POINTS), SetDataTip(STR_FRAMERATE_DATA_POINTS, 0x0),
+		EndContainer(),
+	EndContainer(),
+};
+
+struct FramerateWindow : Window {
+	bool small;
+	uint32 next_update;
+
+	struct CachedDecimal {
+		StringID strid;
+		uint32 value;
+
+		inline void SetRate(double value, double target)
+		{
+			const double threshold_good = target * 0.95;
+			const double threshold_bad = target * 2 / 3;
+			value = min(9999.99, value);
+			this->value = (uint32)(value * 100);
+			this->strid = (value > threshold_good) ? STR_FRAMERATE_FPS_GOOD : (value < threshold_bad) ? STR_FRAMERATE_FPS_BAD : STR_FRAMERATE_FPS_WARN;
+		}
+
+		inline void SetTime(double value, double target)
+		{
+			const double threshold_good = target / 3;
+			const double threshold_bad = target;
+			value = min(9999.99, value);
+			this->value = (uint32)(value * 100);
+			this->strid = (value < threshold_good) ? STR_FRAMERATE_MS_GOOD : (value > threshold_bad) ? STR_FRAMERATE_MS_BAD : STR_FRAMERATE_MS_WARN;
+		}
+
+		inline void InsertDParams(uint n) const
+		{
+			SetDParam(n, this->value);
+			SetDParam(n + 1, 2);
+		}
+	};
+
+	CachedDecimal rate_gameloop;            ///< cached game loop tick rate
+	CachedDecimal rate_drawing;             ///< cached drawing frame rate
+	CachedDecimal speed_gameloop;           ///< cached game loop speed factor
+	CachedDecimal times_shortterm[PFE_MAX]; ///< cached short term average times
+	CachedDecimal times_longterm[PFE_MAX];  ///< cached long term average times
+
+	static const int VSPACING = 3; ///< space between column heading and values
+
+	FramerateWindow(WindowDesc *desc, WindowNumber number) : Window(desc)
+	{
+		this->InitNested(number);
+		this->small = this->IsShaded();
+		this->UpdateData();
+	}
+
+	virtual void OnTick()
+	{
+		/* Check if the shaded state has changed, switch caption text if it has */
+		if (this->small != this->IsShaded()) {
+			this->small = this->IsShaded();
+			this->GetWidget<NWidgetLeaf>(WID_FRW_CAPTION)->SetDataTip(this->small ? STR_FRAMERATE_CAPTION_SMALL : STR_FRAMERATE_CAPTION, STR_TOOLTIP_WINDOW_TITLE_DRAG_THIS);
+			this->next_update = 0;
+		}
+
+		if (_realtime_tick >= this->next_update) {
+			this->UpdateData();
+			this->SetDirty();
+			this->next_update = _realtime_tick + 100;
+		}
+	}
+
+	void UpdateData()
+	{
+		double gl_rate = _pf_data[PFE_GAMELOOP].GetRate();
+		this->rate_gameloop.SetRate(gl_rate, _pf_data[PFE_GAMELOOP].expected_rate);
+		this->speed_gameloop.SetRate(gl_rate / _pf_data[PFE_GAMELOOP].expected_rate, 1.0);
+		if (this->small) return; // in small mode, this is everything needed
+
+		this->rate_drawing.SetRate(_pf_data[PFE_DRAWING].GetRate(), _pf_data[PFE_DRAWING].expected_rate);
+
+		for (PerformanceElement e = PFE_FIRST; e < PFE_MAX; e++) {
+			this->times_shortterm[e].SetTime(_pf_data[e].GetAverageDurationMilliseconds(8), MILLISECONDS_PER_TICK);
+			this->times_longterm[e].SetTime(_pf_data[e].GetAverageDurationMilliseconds(NUM_FRAMERATE_POINTS), MILLISECONDS_PER_TICK);
+		}
+	}
+
+	virtual void SetStringParameters(int widget) const
+	{
+		switch (widget) {
+			case WID_FRW_CAPTION:
+				/* When the window is shaded, the caption shows game loop rate and speed factor */
+				if (!this->small) break;
+				SetDParam(0, this->rate_gameloop.strid);
+				this->rate_gameloop.InsertDParams(1);
+				this->speed_gameloop.InsertDParams(3);
+				break;
+
+			case WID_FRW_RATE_GAMELOOP:
+				SetDParam(0, this->rate_gameloop.strid);
+				this->rate_gameloop.InsertDParams(1);
+				break;
+			case WID_FRW_RATE_DRAWING:
+				SetDParam(0, this->rate_drawing.strid);
+				this->rate_drawing.InsertDParams(1);
+				break;
+			case WID_FRW_RATE_FACTOR:
+				this->speed_gameloop.InsertDParams(0);
+				break;
+			case WID_FRW_INFO_DATA_POINTS:
+				SetDParam(0, NUM_FRAMERATE_POINTS);
+				break;
+		}
+	}
+
+	virtual void UpdateWidgetSize(int widget, Dimension *size, const Dimension &padding, Dimension *fill, Dimension *resize)
+	{
+		switch (widget) {
+			case WID_FRW_RATE_GAMELOOP:
+				SetDParam(0, STR_FRAMERATE_FPS_GOOD);
+				SetDParam(1, 999999);
+				SetDParam(2, 2);
+				*size = GetStringBoundingBox(STR_FRAMERATE_RATE_GAMELOOP);
+				break;
+			case WID_FRW_RATE_DRAWING:
+				SetDParam(0, STR_FRAMERATE_FPS_GOOD);
+				SetDParam(1, 999999);
+				SetDParam(2, 2);
+				*size = GetStringBoundingBox(STR_FRAMERATE_RATE_BLITTER);
+				break;
+			case WID_FRW_RATE_FACTOR:
+				SetDParam(0, 999999);
+				SetDParam(1, 2);
+				*size = GetStringBoundingBox(STR_FRAMERATE_SPEED_FACTOR);
+				break;
+
+			case WID_FRW_TIMES_NAMES: {
+				int linecount = PFE_MAX - PFE_FIRST;
+				size->width = 0;
+				size->height = FONT_HEIGHT_NORMAL * (linecount + 1) + VSPACING;
+				for (int line = 0; line < linecount; line++) {
+					Dimension line_size = GetStringBoundingBox(STR_FRAMERATE_GAMELOOP + line);
+					size->width = max(size->width, line_size.width);
+				}
+				break;
+			}
+
+			case WID_FRW_TIMES_CURRENT:
+			case WID_FRW_TIMES_AVERAGE: {
+				int linecount = PFE_MAX - PFE_FIRST;
+				*size = GetStringBoundingBox(STR_FRAMERATE_CURRENT + (widget - WID_FRW_TIMES_CURRENT));
+				SetDParam(0, 999999);
+				SetDParam(1, 2);
+				Dimension item_size = GetStringBoundingBox(STR_FRAMERATE_MS_GOOD);
+				size->width = max(size->width, item_size.width);
+				size->height += FONT_HEIGHT_NORMAL * linecount + VSPACING;
+				break;
+			}
+		}
+	}
+
+	/** Render a column of formatted average durations */
+	void DrawElementTimesColumn(const Rect &r, StringID heading_str, const CachedDecimal *values) const
+	{
+		int y = r.top;
+		DrawString(r.left, r.right, y, heading_str, TC_FROMSTRING, SA_CENTER);
+		y += FONT_HEIGHT_NORMAL + VSPACING;
+
+		for (PerformanceElement e = PFE_FIRST; e < PFE_MAX; e++) {
+			values[e].InsertDParams(0);
+			DrawString(r.left, r.right, y, values[e].strid, TC_FROMSTRING, SA_RIGHT);
+			y += FONT_HEIGHT_NORMAL;
+		}
+	}
+
+	virtual void DrawWidget(const Rect &r, int widget) const
+	{
+		switch (widget) {
+			case WID_FRW_TIMES_NAMES: {
+				/* Render a column of titles for performance element names */
+				int linecount = PFE_MAX - PFE_FIRST;
+				int y = r.top + FONT_HEIGHT_NORMAL + VSPACING; // first line contains headings in the value columns
+				for (int i = 0; i < linecount; i++) {
+					DrawString(r.left, r.right, y, STR_FRAMERATE_GAMELOOP + i, TC_FROMSTRING, SA_LEFT);
+					y += FONT_HEIGHT_NORMAL;
+				}
+				break;
+			}
+			case WID_FRW_TIMES_CURRENT:
+				/* Render short-term average values */
+				DrawElementTimesColumn(r, STR_FRAMERATE_CURRENT, this->times_shortterm);
+				break;
+			case WID_FRW_TIMES_AVERAGE:
+				/* Render averages of all recorded values */
+				DrawElementTimesColumn(r, STR_FRAMERATE_AVERAGE, this->times_longterm);
+				break;
+		}
+	}
+
+	virtual void OnClick(Point pt, int widget, int click_count)
+	{
+		switch (widget) {
+			case WID_FRW_TIMES_NAMES:
+			case WID_FRW_TIMES_CURRENT:
+			case WID_FRW_TIMES_AVERAGE: {
+				/* Open time graph windows when clicking detail measurement lines */
+				int line = this->GetRowFromWidget(pt.y, widget, VSPACING, FONT_HEIGHT_NORMAL);
+				if (line > 0) {
+					line -= 1;
+					ShowFrametimeGraphWindow((PerformanceElement)line);
+				}
+				break;
+			}
+		}
+	}
+};
+
+static WindowDesc _framerate_display_desc(
+	WDP_AUTO, "framerate_display", 60, 40,
+	WC_FRAMERATE_DISPLAY, WC_NONE,
+	0,
+	_framerate_window_widgets, lengthof(_framerate_window_widgets)
+);
+
+
+enum FrametimeGraphWindowWidgets {
+	WID_FGW_CAPTION,
+	WID_FGW_GRAPH,
+};
+
+static const NWidgetPart _frametime_graph_window_widgets[] = {
+	NWidget(NWID_HORIZONTAL),
+		NWidget(WWT_CLOSEBOX, COLOUR_GREY),
+		NWidget(WWT_CAPTION, COLOUR_GREY, WID_FGW_CAPTION), SetDataTip(STR_WHITE_STRING, STR_TOOLTIP_WINDOW_TITLE_DRAG_THIS),
+		NWidget(WWT_STICKYBOX, COLOUR_GREY),
+	EndContainer(),
+	NWidget(WWT_PANEL, COLOUR_GREY),
+		NWidget(NWID_VERTICAL), SetPadding(6),
+			NWidget(WWT_EMPTY, COLOUR_GREY, WID_FGW_GRAPH),
+		EndContainer(),
+	EndContainer(),
+};
+
+struct FrametimeGraphWindow : Window {
+	int vertical_scale;       ///< number of TIMESTAMP_PRECISION units vertically
+	int horizontal_scale;     ///< number of half-second units horizontally
+	uint32 next_scale_update; ///< realtime tick for next scale update
+
+	PerformanceElement element; ///< what element this window renders graph for
+	Dimension graph_size;       ///< size of the main graph area (excluding axis labels)
+
+	FrametimeGraphWindow(WindowDesc *desc, WindowNumber number) : Window(desc)
+	{
+		this->element = (PerformanceElement)number;
+		this->horizontal_scale = 4;
+		this->vertical_scale = TIMESTAMP_PRECISION / 10;
+		this->next_scale_update = 0;
+
+		this->InitNested(number);
+	}
+
+	virtual void SetStringParameters(int widget) const
+	{
+		switch (widget) {
+			case WID_FGW_CAPTION:
+				SetDParam(0, STR_FRAMETIME_CAPTION_GAMELOOP + this->element);
+				break;
+		}
+	}
+
+	virtual void UpdateWidgetSize(int widget, Dimension *size, const Dimension &padding, Dimension *fill, Dimension *resize)
+	{
+		if (widget == WID_FGW_GRAPH) {
+			SetDParam(0, 100);
+			Dimension size_ms_label = GetStringBoundingBox(STR_FRAMERATE_GRAPH_MILLISECONDS);
+			SetDParam(0, 100);
+			Dimension size_s_label = GetStringBoundingBox(STR_FRAMERATE_GRAPH_SECONDS);
+
+			/* Size graph in height to fit at least 10 vertical labels with space between, or at least 100 pixels */
+			graph_size.height = max<uint>(100, 10 * (size_ms_label.height + 1));
+			/* Always 2:1 graph area */
+			graph_size.width = 2 * graph_size.height;
+			*size = graph_size;
+
+			size->width += size_ms_label.width + 2;
+			size->height += size_s_label.height + 2;
+		}
+	}
+
+	void SelectHorizontalScale(TimingMeasurement range)
+	{
+		/* Determine horizontal scale based on period covered by 60 points
+		* (slightly less than 2 seconds at full game speed) */
+		struct ScaleDef { TimingMeasurement range; int scale; };
+		static const ScaleDef hscales[] = {
+			{ 120, 60 },
+			{  10, 20 },
+			{   5, 10 },
+			{   3,  4 },
+			{   1,  2 },
+		};
+		for (const ScaleDef *sc = hscales; sc < hscales + lengthof(hscales); sc++) {
+			if (range < sc->range) this->horizontal_scale = sc->scale;
+		}
+	}
+
+	void SelectVerticalScale(TimingMeasurement range)
+	{
+		/* Determine vertical scale based on peak value (within the horizontal scale + a bit) */
+		static const TimingMeasurement vscales[] = {
+			TIMESTAMP_PRECISION * 100,
+			TIMESTAMP_PRECISION * 10,
+			TIMESTAMP_PRECISION * 5,
+			TIMESTAMP_PRECISION,
+			TIMESTAMP_PRECISION / 2,
+			TIMESTAMP_PRECISION / 5,
+			TIMESTAMP_PRECISION / 10,
+			TIMESTAMP_PRECISION / 50,
+			TIMESTAMP_PRECISION / 200,
+		};
+		for (const TimingMeasurement *sc = vscales; sc < vscales + lengthof(vscales); sc++) {
+			if (range < *sc) this->vertical_scale = (int)*sc;
+		}
+	}
+
+	/** Recalculate the graph scaling factors based on current recorded data */
+	void UpdateScale()
+	{
+		const TimingMeasurement *durations = _pf_data[this->element].durations;
+		const TimingMeasurement *timestamps = _pf_data[this->element].timestamps;
+		int num_valid = _pf_data[this->element].num_valid;
+		int point = _pf_data[this->element].prev_index;
+
+		TimingMeasurement lastts = timestamps[point];
+		TimingMeasurement time_sum = 0;
+		TimingMeasurement peak_value = 0;
+		int count = 0;
+
+		/* Sensible default for when too few measurements are available */
+		this->horizontal_scale = 4;
+
+		for (int i = 1; i < num_valid; i++) {
+			point--;
+			if (point < 0) point = NUM_FRAMERATE_POINTS - 1;
+
+			TimingMeasurement value = durations[point];
+			if (value == PerformanceData::INVALID_DURATION) {
+				/* Skip gaps in data by pretending time is continuous across them */
+				lastts = timestamps[point];
+				continue;
+			}
+			if (value > peak_value) peak_value = value;
+			count++;
+
+			/* Accumulate period of time covered by data */
+			time_sum += lastts - timestamps[point];
+			lastts = timestamps[point];
+
+			/* Enough data to select a range and get decent data density */
+			if (count == 60) this->SelectHorizontalScale(time_sum / TIMESTAMP_PRECISION);
+
+			/* End when enough points have been collected and the horizontal scale has been exceeded */
+			if (count >= 60 && time_sum >= (this->horizontal_scale + 2) * TIMESTAMP_PRECISION / 2) break;
+		}
+
+		this->SelectVerticalScale(peak_value);
+	}
+
+	virtual void OnTick()
+	{
+		this->SetDirty();
+
+		if (this->next_scale_update < _realtime_tick) {
+			this->next_scale_update = _realtime_tick + 500;
+			this->UpdateScale();
+		}
+	}
+
+	/** Scale and interpolate a value from a source range into a destination range */
+	template<typename T>
+	static inline T Scinterlate(T dst_min, T dst_max, T src_min, T src_max, T value)
+	{
+		T dst_diff = dst_max - dst_min;
+		T src_diff = src_max - src_min;
+		return (value - src_min) * dst_diff / src_diff + dst_min;
+	}
+
+	virtual void DrawWidget(const Rect &r, int widget) const
+	{
+		if (widget == WID_FGW_GRAPH) {
+			const TimingMeasurement *durations  = _pf_data[this->element].durations;
+			const TimingMeasurement *timestamps = _pf_data[this->element].timestamps;
+			int point = _pf_data[this->element].prev_index;
+
+			const int x_zero = r.right - (int)this->graph_size.width;
+			const int x_max = r.right;
+			const int y_zero = r.top + (int)this->graph_size.height;
+			const int y_max = r.top;
+			const int c_grid = PC_DARK_GREY;
+			const int c_lines = PC_BLACK;
+			const int c_peak = PC_DARK_RED;
+
+			const TimingMeasurement draw_horz_scale = (TimingMeasurement)this->horizontal_scale * TIMESTAMP_PRECISION / 2;
+			const TimingMeasurement draw_vert_scale = (TimingMeasurement)this->vertical_scale;
+
+			/* Number of \c horizontal_scale units in each horizontal division */
+			const uint horz_div_scl = (this->horizontal_scale <= 20) ? 1 : 10;
+			/* Number of divisions of the horizontal axis */
+			const uint horz_divisions = this->horizontal_scale / horz_div_scl;
+			/* Number of divisions of the vertical axis */
+			const uint vert_divisions = 10;
+
+			/* Draw division lines and labels for the vertical axis */
+			for (uint division = 0; division < vert_divisions; division++) {
+				int y = Scinterlate(y_zero, y_max, 0, (int)vert_divisions, (int)division);
+				GfxDrawLine(x_zero, y, x_max, y, c_grid);
+				if (division % 2 == 0) {
+					if ((TimingMeasurement)this->vertical_scale > TIMESTAMP_PRECISION) {
+						SetDParam(0, this->vertical_scale * division / 10 / TIMESTAMP_PRECISION);
+						DrawString(r.left, x_zero - 2, y - FONT_HEIGHT_SMALL, STR_FRAMERATE_GRAPH_SECONDS, TC_GREY, SA_RIGHT | SA_FORCE, false, FS_SMALL);
+					} else {
+						SetDParam(0, this->vertical_scale * division / 10 * 1000 / TIMESTAMP_PRECISION);
+						DrawString(r.left, x_zero - 2, y - FONT_HEIGHT_SMALL, STR_FRAMERATE_GRAPH_MILLISECONDS, TC_GREY, SA_RIGHT | SA_FORCE, false, FS_SMALL);
+					}
+				}
+			}
+			/* Draw divison lines and labels for the horizontal axis */
+			for (uint division = horz_divisions; division > 0; division--) {
+				int x = Scinterlate(x_zero, x_max, 0, (int)horz_divisions, (int)horz_divisions - (int)division);
+				GfxDrawLine(x, y_max, x, y_zero, c_grid);
+				if (division % 2 == 0) {
+					SetDParam(0, division * horz_div_scl / 2);
+					DrawString(x, x_max, y_zero + 2, STR_FRAMERATE_GRAPH_SECONDS, TC_GREY, SA_LEFT | SA_FORCE, false, FS_SMALL);
+				}
+			}
+
+			/* Position of last rendered data point */
+			Point lastpoint = {
+				x_max,
+				(int)Scinterlate<int64>(y_zero, y_max, 0, this->vertical_scale, durations[point])
+			};
+			/* Timestamp of last rendered data point */
+			TimingMeasurement lastts = timestamps[point];
+
+			TimingMeasurement peak_value = 0;
+			Point peak_point = { 0, 0 };
+			TimingMeasurement value_sum = 0;
+			TimingMeasurement time_sum = 0;
+			int points_drawn = 0;
+
+			for (int i = 1; i < NUM_FRAMERATE_POINTS; i++) {
+				point--;
+				if (point < 0) point = NUM_FRAMERATE_POINTS - 1;
+
+				TimingMeasurement value = durations[point];
+				if (value == PerformanceData::INVALID_DURATION) {
+					/* Skip gaps in measurements, pretend the data points on each side are continuous */
+					lastts = timestamps[point];
+					continue;
+				}
+
+				/* Use total time period covered for value along horizontal axis */
+				time_sum += lastts - timestamps[point];
+				lastts = timestamps[point];
+				/* Stop if past the width of the graph */
+				if (time_sum > draw_horz_scale) break;
+
+				/* Draw line from previous point to new point */
+				Point newpoint = {
+					(int)Scinterlate<int64>(x_zero, x_max, 0, (int64)draw_horz_scale, (int64)draw_horz_scale - (int64)time_sum),
+					(int)Scinterlate<int64>(y_zero, y_max, 0, (int64)draw_vert_scale, (int64)value)
+				};
+				assert(newpoint.x <= lastpoint.x);
+				GfxDrawLine(lastpoint.x, lastpoint.y, newpoint.x, newpoint.y, c_lines);
+				lastpoint = newpoint;
+
+				/* Record peak and average value across graphed data */
+				value_sum += value;
+				points_drawn++;
+				if (value > peak_value) {
+					peak_value = value;
+					peak_point = newpoint;
+				}
+			}
+
+			/* If the peak value is significantly larger than the average, mark and label it */
+			if (points_drawn > 0 && peak_value > TIMESTAMP_PRECISION / 100 && 2 * peak_value > 3 * value_sum / points_drawn) {
+				TextColour tc_peak = (TextColour)(TC_IS_PALETTE_COLOUR | c_peak);
+				GfxFillRect(peak_point.x - 1, peak_point.y - 1, peak_point.x + 1, peak_point.y + 1, c_peak);
+				SetDParam(0, peak_value * 1000 / TIMESTAMP_PRECISION);
+				int label_y = max(y_max, peak_point.y - FONT_HEIGHT_SMALL);
+				if (peak_point.x - x_zero > (int)this->graph_size.width / 2) {
+					DrawString(x_zero, peak_point.x - 2, label_y, STR_FRAMERATE_GRAPH_MILLISECONDS, tc_peak, SA_RIGHT | SA_FORCE, false, FS_SMALL);
+				} else {
+					DrawString(peak_point.x + 2, x_max, label_y, STR_FRAMERATE_GRAPH_MILLISECONDS, tc_peak, SA_LEFT | SA_FORCE, false, FS_SMALL);
+				}
+			}
+		}
+	}
+};
+
+static WindowDesc _frametime_graph_window_desc(
+	WDP_AUTO, "frametime_graph", 140, 90,
+	WC_FRAMETIME_GRAPH, WC_NONE,
+	0,
+	_frametime_graph_window_widgets, lengthof(_frametime_graph_window_widgets)
+);
+
+
+
+void ShowFramerateWindow()
+{
+	AllocateWindowDescFront<FramerateWindow>(&_framerate_display_desc, 0);
+}
+
+void ShowFrametimeGraphWindow(PerformanceElement elem)
+{
+	if (elem < PFE_FIRST || elem >= PFE_MAX) return; // maybe warn?
+	AllocateWindowDescFront<FrametimeGraphWindow>(&_frametime_graph_window_desc, elem, true);
+}
+
+void ConPrintFramerate()
+{
+	const int count1 = NUM_FRAMERATE_POINTS / 8;
+	const int count2 = NUM_FRAMERATE_POINTS / 4;
+	const int count3 = NUM_FRAMERATE_POINTS / 1;
+
+	IConsolePrintF(TC_SILVER, "Based on num. data points: %d %d %d", count1, count2, count3);
+
+	static const char *MEASUREMENT_NAMES[PFE_MAX] = {
+		"Game loop",
+		"  GL station ticks",
+		"  GL train ticks",
+		"  GL road vehicle ticks",
+		"  GL ship ticks",
+		"  GL aircraft ticks",
+		"  GL landscape ticks",
+		"  GL link graph delays",
+		"Drawing",
+		"  Viewport drawing",
+		"Video output",
+		"Sound mixing",
+	};
+
+	static const PerformanceElement rate_elements[] = { PFE_GAMELOOP, PFE_DRAWING, PFE_VIDEO };
+
+	bool printed_anything = false;
+
+	for (const PerformanceElement *e = rate_elements; e < rate_elements + lengthof(rate_elements); e++) {
+		auto &pf = _pf_data[*e];
+		if (pf.num_valid == 0) continue;
+		IConsolePrintF(TC_GREEN, "%s rate: %.2ffps  (expected: %.2ffps)",
+			MEASUREMENT_NAMES[*e],
+			pf.GetRate(),
+			pf.expected_rate);
+		printed_anything = true;
+	}
+
+	for (PerformanceElement e = PFE_FIRST; e < PFE_MAX; e++) {
+		auto &pf = _pf_data[e];
+		if (pf.num_valid == 0) continue;
+		IConsolePrintF(TC_LIGHT_BLUE, "%s times: %.2fms  %.2fms  %.2fms",
+			MEASUREMENT_NAMES[e],
+			pf.GetAverageDurationMilliseconds(count1),
+			pf.GetAverageDurationMilliseconds(count2),
+			pf.GetAverageDurationMilliseconds(count3));
+		printed_anything = true;
+	}
+
+	if (!printed_anything) {
+		IConsoleWarning("No performance measurements have been taken yet");
+	}
+}