From b18e53417af84f4f30f972213e0dade3ad640942 Mon Sep 17 00:00:00 2001
From: Sally Coolatta <tehrealsalt@gmail.com>
Date: Tue, 19 Apr 2022 12:06:17 -0400
Subject: [PATCH] Handle the sleep at the end of D_SRB2Loop instead of the
start
Simplifies logic in the other parts of the loop, and fixes problems with it frequently waiting too long.
---
src/d_main.c | 75 +++++++++++++-------------------------------
src/i_system.h | 8 +++--
src/screen.c | 9 +++---
src/sdl/i_system.c | 77 +++++++++++++++++++++++++++-------------------
4 files changed, 79 insertions(+), 90 deletions(-)
diff --git a/src/d_main.c b/src/d_main.c
index 470ec4fb72..f29fdd2249 100644
--- a/src/d_main.c
+++ b/src/d_main.c
@@ -687,29 +687,6 @@ static void D_Display(void)
}
}
-static boolean D_CheckFrameCap(void)
-{
- static boolean init = false;
- static precise_t startCap = 0;
- precise_t endCap = 0;
-
- endCap = I_GetPreciseTime();
-
- if (init == false)
- {
- startCap = endCap;
- init = true;
- }
- else if (I_CheckFrameCap(startCap, endCap))
- {
- // Framerate should be capped.
- return true;
- }
-
- startCap = endCap;
- return false;
-}
-
// =========================================================================
// D_SRB2Loop
// =========================================================================
@@ -720,10 +697,13 @@ void D_SRB2Loop(void)
{
tic_t oldentertics = 0, entertic = 0, realtics = 0, rendertimeout = INFTICS;
static lumpnum_t gstartuplumpnum;
- boolean ticked;
- boolean interp;
+
+ boolean ticked = false;
+ boolean interp = false;
boolean doDisplay = false;
- boolean frameCap = false;
+
+ precise_t frameTime = 0;
+ int frameElapsed = 0;
if (dedicated)
server = true;
@@ -775,6 +755,9 @@ void D_SRB2Loop(void)
for (;;)
{
+ frameTime = I_GetPreciseTime();
+ frameElapsed = 0;
+
if (lastwipetic)
{
oldentertics = lastwipetic;
@@ -804,19 +787,6 @@ void D_SRB2Loop(void)
doDisplay = false;
ticked = false;
- frameCap = D_CheckFrameCap();
-
- // Moved to here from I_FinishUpdate.
- // It doesn't track fades properly anymore by being here (might be easy fix),
- // but it's a little more accurate for actual rendering when its here.
- SCR_CalculateFPS();
-
- if (!realtics && !singletics)
- {
- if (frameCap)
- continue;
- }
-
#ifdef HW3SOUND
HW3S_BeginFrameUpdate();
#endif
@@ -872,15 +842,6 @@ void D_SRB2Loop(void)
tictime = entertime;
}
- // Handle interp sleep / framerate cap here.
- // TryRunTics needs ran if possible to prevent lagged map changes,
- // (and if that runs, the code above needs to also run)
- // so this is done here after TryRunTics.
- if (frameCap)
- {
- continue;
- }
-
if (!(paused || P_AutoPause()))
{
#if 0
@@ -912,11 +873,6 @@ void D_SRB2Loop(void)
}
else
{
- if (frameCap)
- {
- continue;
- }
-
renderdeltatics = realtics * FRACUNIT;
rendertimefrac = FRACUNIT;
}
@@ -940,6 +896,19 @@ void D_SRB2Loop(void)
#endif
LUA_Step();
+
+ // Moved to here from I_FinishUpdate.
+ // It doesn't track fades properly anymore by being here (might be easy fix),
+ // but it's a little more accurate for actual rendering when its here.
+ SCR_CalculateFPS();
+
+ // Fully completed frame made, handle frame cap delay.
+ frameElapsed = I_PreciseToMicros(I_GetPreciseTime() - frameTime);
+
+ if (!singletics)
+ {
+ I_FrameCapSleep(frameElapsed);
+ }
}
}
diff --git a/src/i_system.h b/src/i_system.h
index fefe0a7c12..f813135cef 100644
--- a/src/i_system.h
+++ b/src/i_system.h
@@ -58,13 +58,17 @@ precise_t I_GetPreciseTime(void);
*/
int I_PreciseToMicros(precise_t d);
-/** \brief The I_Sleep function
+/** \brief Sleeps by the value of cv_sleep
\return void
*/
void I_Sleep(void);
-boolean I_CheckFrameCap(precise_t start, precise_t end);
+/** \brief Sleeps for a variable amount of time, depending on how much time the last frame took.
+
+ \return void
+*/
+boolean I_FrameCapSleep(const int elapsed);
/** \brief Get events
diff --git a/src/screen.c b/src/screen.c
index b51b5472f8..6ad36273b7 100644
--- a/src/screen.c
+++ b/src/screen.c
@@ -509,7 +509,7 @@ void SCR_DisplayTicRate(void)
INT32 ticcntcolor = 0;
const INT32 h = vid.height-(8*vid.dupy);
UINT32 cap = R_GetFramerateCap();
- double fps = ceil(averageFPS);
+ double fps = round(averageFPS);
if (gamestate == GS_NULL)
return;
@@ -525,10 +525,11 @@ void SCR_DisplayTicRate(void)
ticcntcolor = V_GREENMAP;
}
-
if (cv_ticrate.value == 2) // compact counter
- V_DrawString(vid.width-(32*vid.dupx), h,
- ticcntcolor|V_NOSCALESTART|V_USERHUDTRANS, va("%04.0f", fps));
+ {
+ V_DrawRightAlignedString(vid.width, h,
+ ticcntcolor|V_NOSCALESTART|V_USERHUDTRANS, va("%04.2f", averageFPS)); // use averageFPS directly
+ }
else if (cv_ticrate.value == 1) // full counter
{
if (cap > 0)
diff --git a/src/sdl/i_system.c b/src/sdl/i_system.c
index b3db8b455c..428186f307 100644
--- a/src/sdl/i_system.c
+++ b/src/sdl/i_system.c
@@ -2167,6 +2167,10 @@ float I_GetTimeFrac(void)
return elapsed_tics;
}
+//
+// I_GetPreciseTime
+// returns time in precise_t
+//
precise_t I_GetPreciseTime(void)
{
return SDL_GetPerformanceCounter();
@@ -2184,7 +2188,7 @@ int I_PreciseToMicros(precise_t d)
}
//
-//I_StartupTimer
+// I_StartupTimer
//
void I_StartupTimer(void)
{
@@ -2195,71 +2199,82 @@ void I_StartupTimer(void)
elapsed_tics = 0.0;
}
+//
+// I_Sleep
+// Sleeps by the value of cv_sleep
+//
void I_Sleep(void)
{
if (cv_sleep.value != -1)
SDL_Delay(cv_sleep.value);
}
-boolean I_CheckFrameCap(precise_t start, precise_t end)
+//
+// I_FrameCapSleep
+// Sleeps for a variable amount of time, depending on how much time the last frame took.
+//
+boolean I_FrameCapSleep(const int elapsed)
{
+ const INT64 delayGranularity = 2000;
+ // I picked 2ms as it's what GZDoom uses before it stops trying to sleep,
+ // but maybe other values might work better.
+
const UINT32 capFrames = R_GetFramerateCap();
int capMicros = 0;
- int elapsed;
-
if (capFrames == 0)
{
// We don't want to cap.
return false;
}
- elapsed = I_PreciseToMicros(end - start);
capMicros = 1000000 / capFrames;
if (elapsed < capMicros)
{
- // Experimental variable delay code.
- if (cv_sleep.value > 0)
+ const INT64 error = capMicros / 40;
+ // 2.5% ... How much we might expect the framerate to flucuate.
+ // No exact logic behind this number, simply tried stuff until the framerate
+ // reached the cap 300 more often and only overshot it occasionally.
+
+ INT64 wait = (capMicros - elapsed) - error;
+
+ while (wait > 0)
{
- const INT64 delayGranularity = 2000; // 2ms, I picked this as it's what GZDoom uses before it stops trying to sleep.
- INT64 wait = (capMicros - elapsed);
+ precise_t sleepStart = I_GetPreciseTime();
+ precise_t sleepEnd = sleepStart;
+ int sleepElasped = 0;
- while (wait > 0)
+ if (wait > delayGranularity && cv_sleep.value != -1)
{
- precise_t sleepStart = I_GetPreciseTime();
- precise_t sleepEnd = sleepStart;
- int sleepElasped = 0;
+ // Wait 1ms at a time (on default settings)
+ // until we're close enough.
+ SDL_Delay(cv_sleep.value);
- if (wait > delayGranularity)
+ sleepEnd = I_GetPreciseTime();
+ sleepElasped = I_PreciseToMicros(sleepEnd - sleepStart);
+ }
+ else
+ {
+ // When we have an extremely fine wait,
+ // we do this to spin-lock the remaining time.
+ while (sleepElasped < wait)
{
- // Wait 1ms at a time (on default settings)
- // until we're close enough.
- SDL_Delay(cv_sleep.value);
-
sleepEnd = I_GetPreciseTime();
sleepElasped = I_PreciseToMicros(sleepEnd - sleepStart);
}
- else
- {
- // When we have an extremely fine wait,
- // we do this to spin-lock the remaining time.
- while (sleepElasped < wait)
- {
- sleepEnd = I_GetPreciseTime();
- sleepElasped = I_PreciseToMicros(sleepEnd - sleepStart);
- }
- }
-
- wait -= sleepElasped;
+ break;
}
+
+ wait -= sleepElasped;
}
+ // We took our nap.
return true;
}
- // Waited enough to draw again.
+ // We're lagging behind.
return false;
}
--
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