Get rid of a lot of ifdefs around presentation mode. Instead, set things dynamically.

Core/FrameTiming.cpp

@@ -10,3 +10,65 @@
 #include "Core/FrameTiming.h"
 
 FrameTiming g_frameTiming;
+
+inline Draw::PresentMode GetBestImmediateMode(Draw::PresentMode supportedModes) {
+	if (supportedModes & Draw::PresentMode::MAILBOX) {
+		return Draw::PresentMode::MAILBOX;
+	} else {
+		return Draw::PresentMode::IMMEDIATE;
+	}
+}
+
+void FrameTiming::Reset(Draw::DrawContext *draw) {
+	if (g_Config.bVSync) {
+		presentMode = Draw::PresentMode::FIFO;
+		presentInterval = 1;
+	} else {
+		presentMode = GetBestImmediateMode(draw->GetDeviceCaps().presentModesSupported);
+		presentInterval = 0;
+	}
+}
+
+Draw::PresentMode ComputePresentMode(Draw::DrawContext *draw, int *interval) {
+	Draw::PresentMode mode = Draw::PresentMode::FIFO;
+
+	if (draw->GetDeviceCaps().presentModesSupported & (Draw::PresentMode::IMMEDIATE | Draw::PresentMode::MAILBOX)) {
+		// Switch to immediate if desired and possible.
+		bool wantInstant = false;
+		if (!g_Config.bVSync) {
+			wantInstant = true;
+		}
+
+		if (PSP_CoreParameter().fastForward) {
+			wantInstant = true;
+		}
+		if (PSP_CoreParameter().fpsLimit != FPSLimit::NORMAL) {
+			int limit;
+			if (PSP_CoreParameter().fpsLimit == FPSLimit::CUSTOM1)
+				limit = g_Config.iFpsLimit1;
+			else if (PSP_CoreParameter().fpsLimit == FPSLimit::CUSTOM2)
+				limit = g_Config.iFpsLimit2;
+			else
+				limit = PSP_CoreParameter().analogFpsLimit;
+
+			// For an alternative speed that is a clean factor of 60, the user probably still wants vsync.
+			if (limit == 0 || (limit >= 0 && limit != 15 && limit != 30 && limit != 60)) {
+				wantInstant = true;
+			}
+		}
+
+		if (wantInstant && g_Config.bVSync && !draw->GetDeviceCaps().presentInstantModeChange) {
+			// If in vsync mode (which will be FIFO), and the backend can't switch immediately,
+			// stick to FIFO.
+			wantInstant = false;
+		}
+
+		// If no instant modes are supported, stick to FIFO.
+		if (wantInstant && (draw->GetDeviceCaps().presentModesSupported & (Draw::PresentMode::MAILBOX | Draw::PresentMode::IMMEDIATE))) {
+			mode = GetBestImmediateMode(draw->GetDeviceCaps().presentModesSupported);
+		}
+	}
+
+	*interval = (mode == Draw::PresentMode::FIFO) ? 1 : 0;
+	return mode;
+}