From 97dd427407393920b1badd3fdd13d00d9aadac7e Mon Sep 17 00:00:00 2001 From: nitsuja Date: Sun, 15 Nov 2009 00:49:02 +0000 Subject: [PATCH] possibly-slightly-better-behaving autoframeskip logic. It's still not completely immune to FPS drops, however (because that seems to require either knowledge from the future, systematic over-estimation, or complete disregard for visual consistency, although it can surely be improved somehow). --- desmume/src/windows/hotkey.cpp | 4 + desmume/src/windows/main.cpp | 5 ++ desmume/src/windows/throttle.cpp | 139 +++++++++++++++++++------------ desmume/src/windows/throttle.h | 1 + 4 files changed, 95 insertions(+), 54 deletions(-) diff --git a/desmume/src/windows/hotkey.cpp b/desmume/src/windows/hotkey.cpp index 1f0f1b28a..2d8d2449c 100644 --- a/desmume/src/windows/hotkey.cpp +++ b/desmume/src/windows/hotkey.cpp @@ -145,6 +145,8 @@ void HK_StateSaveSlot(int num, bool justPressed) savestate_slot(num); //Savestate LoadSaveStateInfo(); + + AutoFrameSkip_IgnorePreviousDelay(); } } @@ -164,6 +166,8 @@ void HK_StateLoadSlot(int num, bool justPressed) NDS_UnPause(); else Display(); + + AutoFrameSkip_IgnorePreviousDelay(); } } diff --git a/desmume/src/windows/main.cpp b/desmume/src/windows/main.cpp index e9bf7a924..c25f17331 100644 --- a/desmume/src/windows/main.cpp +++ b/desmume/src/windows/main.cpp @@ -1805,6 +1805,7 @@ static BOOL LoadROM(const char * filename, const char * logicalName) OpenRWRecentFile(0); RamWatchHWnd = CreateDialog(hAppInst, MAKEINTRESOURCE(IDD_RAMWATCH), MainWindow->getHWnd(), (DLGPROC) RamWatchProc); } + if (autoframeskipenab) AutoFrameSkip_IgnorePreviousDelay(); return TRUE; } @@ -3292,6 +3293,7 @@ int HandleKeyMessage(WPARAM wParam, LPARAM lParam, int modifiers) void Unpause() { lastPauseFromLostFocus = FALSE; + if (emu_paused && autoframeskipenab) AutoFrameSkip_IgnorePreviousDelay(); if (!execute && !emu_paused) NDS_Pause(false), emu_paused=true; if (emu_paused) NDS_UnPause(); emu_paused = 0; @@ -3308,6 +3310,7 @@ void Pause() void TogglePause() { lastPauseFromLostFocus = FALSE; + if (emu_paused && autoframeskipenab) AutoFrameSkip_IgnorePreviousDelay(); if (emu_paused) NDS_UnPause(); else NDS_Pause(); emu_paused ^= 1; @@ -3444,6 +3447,7 @@ LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM { case WM_EXITMENULOOP: SPU_Pause(0); + if (autoframeskipenab) AutoFrameSkip_IgnorePreviousDelay(); break; case WM_ENTERMENULOOP: //Update menu items that needs to be updated dynamically { @@ -4746,6 +4750,7 @@ LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM frameskiprate = LOWORD(wParam) - (IDC_FRAMESKIPAUTO1 - 1); sprintf(text, "AUTO%d", frameskiprate); WritePrivateProfileString("Video", "FrameSkip", text, IniName); + AutoFrameSkip_IgnorePreviousDelay(); } return 0; case IDC_FRAMESKIP0: diff --git a/desmume/src/windows/throttle.cpp b/desmume/src/windows/throttle.cpp index 785d671c8..fc4645eb9 100644 --- a/desmume/src/windows/throttle.cpp +++ b/desmume/src/windows/throttle.cpp @@ -6,7 +6,7 @@ #include "../types.h" #include "../debug.h" #include "../console.h" -#include +#include "throttle.h" int FastForward=0; static u64 tmethod,tfreq,afsfreq; @@ -70,17 +70,23 @@ void InitSpeedThrottle(void) else afsfreq=1000; tfreq = afsfreq << 16; + + AutoFrameSkip_IgnorePreviousDelay(); } +static void AutoFrameSkip_BeforeThrottle(); + +static u64 ltime; + void SpeedThrottle() { - static u64 ttime, ltime; + AutoFrameSkip_BeforeThrottle(); waiter: if(FastForward) return; - ttime = GetCurTime(); + u64 ttime = GetCurTime(); if((ttime - ltime) < (tfreq / desiredfps)) { @@ -106,70 +112,79 @@ waiter: // auto frameskip -static u64 beginticks=0, endticks=0, diffticks=0; -static std::vector diffs; -static const int SLIDING_WINDOW_SIZE = 32; +static u64 beginticks=0, endticks=0, preThrottleEndticks=0; static float fSkipFrames = 0; static float fSkipFramesError = 0; -static int minSkip = 0, maxSkip = 9; +static int lastSkip = 0; +static float lastError = 0; +static float integral = 0; -static float maxDiff(const std::vector& diffs) +void AutoFrameSkip_IgnorePreviousDelay() { - float maximum = 0; - for(int i = 0; i < diffs.size(); i++) - if(maximum < diffs[i]) - maximum = diffs[i]; - return maximum; + beginticks = GetCurTime(); + + // this seems to be a stable way of allowing the skip frames to + // quickly adjust to a faster environment (e.g. after a loadstate) + // without causing oscillation or a sudden change in skip rate + fSkipFrames *= 0.5f; } -static void addDiff(float diff, std::vector& diffs) +static void AutoFrameSkip_BeforeThrottle() { - // limit to about double the maximum, to reduce the impact of the occasional huge diffs - // (using the last or average entry is a bad idea because some games do their own frameskipping) - float maximum = maxDiff(diffs); - if(!diffs.empty() && diff > maximum * 2 + 0.0001f) - diff = maximum * 2 + 0.0001f; - - diffs.push_back(diff); - - if(diffs.size() > SLIDING_WINDOW_SIZE) - diffs.erase(diffs.begin()); -} - -static float average(const std::vector& diffs) -{ - float avg = 0; - for(int i = 0; i < diffs.size(); i++) - avg += diffs[i]; - if(diffs.size()) - avg /= diffs.size(); - return avg; + preThrottleEndticks = GetCurTime(); } void AutoFrameSkip_NextFrame() { endticks = GetCurTime(); - diffticks = endticks - beginticks; + // calculate time since last frame + u64 diffticks = endticks - beginticks; float diff = (float)diffticks / afsfreq; - addDiff(diff,diffs); - float avg = average(diffs); - float overby = (avg - (desiredspf + (fSkipFrames + 2) * 0.000025f)) * 8; - // try to avoid taking too long to catch up to the game running fast again - if(overby < 0 && fSkipFrames > 4) - overby = -fSkipFrames / 4; - else if(avg < desiredspf) - overby *= 8; + // calculate time since last frame not including throttle sleep time + if(!preThrottleEndticks) // if we didn't throttle, use the non-throttle time + preThrottleEndticks = endticks; + u64 diffticksUnthrottled = preThrottleEndticks - beginticks; + float diffUnthrottled = (float)diffticksUnthrottled / afsfreq; - fSkipFrames += overby; - if(fSkipFrames < minSkip-1) - fSkipFrames = minSkip-1; - if(fSkipFrames > maxSkip+1) - fSkipFrames = maxSkip+1; - //printf("avg = %g, overby = %g, skipframes = %g\n", avg, overby, fSkipFrames); + float error = diffUnthrottled - desiredspf; + + // reset way-out-of-range values + if(diff > 1) + diff = 1; + if(error > 1 || error < -1) + error = 0; + if(diffUnthrottled > 1) + diffUnthrottled = desiredspf; + + float derivative = (error - lastError) / diff; + lastError = error; + + integral = integral + (error * diff); + integral *= 0.99f; // since our integral isn't reliable, reduce it to 0 over time. + + // "PID controller" constants + // this stuff is probably being done all wrong, but these seem to work ok + static const float Kp = 40.0f; + static const float Ki = 0.55f; + static const float Kd = 0.04f; + + float errorTerm = error * Kp; + float derivativeTerm = derivative * Kd; + float integralTerm = integral * Ki; + float adjustment = errorTerm + derivativeTerm + integralTerm; + + // apply the output adjustment + fSkipFrames += adjustment; + + // if we're running too slowly, prevent the throttle from kicking in + if(adjustment > 0 && fSkipFrames > 0) + ltime-=tfreq/desiredfps; + + preThrottleEndticks = 0; beginticks = GetCurTime(); } @@ -177,25 +192,41 @@ int AutoFrameSkip_GetSkipAmount(int min, int max) { int rv = (int)fSkipFrames; fSkipFramesError += fSkipFrames - rv; - while(fSkipFramesError >= 1.0f) + + // resolve accumulated fractional error + // where doing so doesn't push us out of range + while(fSkipFramesError >= 1.0f && rv <= lastSkip && rv < max) { fSkipFramesError -= 1.0f; rv++; } - while(fSkipFramesError <= -1.0f) + while(fSkipFramesError <= -1.0f && rv >= lastSkip && rv > min) { fSkipFramesError += 1.0f; rv--; } + + // restrict skip amount to requested range if(rv < min) rv = min; if(rv > max) rv = max; - minSkip = min; - maxSkip = max; - //printf("SKIPPED: %d\n", rv); + // limit maximum error accumulation (it's mainly only for fractional components) + if(fSkipFramesError >= 4.0f) + fSkipFramesError = 4.0f; + if(fSkipFramesError <= -4.0f) + fSkipFramesError = -4.0f; + // limit ongoing skipframes to requested range + 1 on each side + if(fSkipFrames < min-1) + fSkipFrames = min-1; + if(fSkipFrames > max+1) + fSkipFrames = max+1; + +// printf("%d", rv); + + lastSkip = rv; return rv; } diff --git a/desmume/src/windows/throttle.h b/desmume/src/windows/throttle.h index 53a792606..5a1968d62 100644 --- a/desmume/src/windows/throttle.h +++ b/desmume/src/windows/throttle.h @@ -9,6 +9,7 @@ void InitSpeedThrottle(); void SpeedThrottle(); void AutoFrameSkip_NextFrame(); +void AutoFrameSkip_IgnorePreviousDelay(); int AutoFrameSkip_GetSkipAmount(int min=0, int max=9); #endif