From 185d3d902dda27b573257bcc588a82abaed9e6a7 Mon Sep 17 00:00:00 2001
From: Glenn Maynard <gmaynard@users.sourceforge.net>
Date: Wed, 5 Apr 2006 05:36:04 +0000
Subject: [PATCH] It's RageDisplay::EndFrame()'s job to give up CPU between
 frames.  Currently, we're doing this partially in EndFrame (in
 FrameLimitBeforeVsync and/or the actual vblank wait), and partially in
 RunGameLoop.  These serve the same purpose, so merge them.

(The renderer itself should have more control over this, but this is an
improvement.)
---
 stepmania/src/GameLoop.cpp    | 11 ----------
 stepmania/src/RageDisplay.cpp | 40 ++++++++++++++++++++++-------------
 2 files changed, 25 insertions(+), 26 deletions(-)

diff --git a/stepmania/src/GameLoop.cpp b/stepmania/src/GameLoop.cpp
index 49b1433ac6..b9b3b599b2 100644
--- a/stepmania/src/GameLoop.cpp
+++ b/stepmania/src/GameLoop.cpp
@@ -179,17 +179,6 @@ void GameLoop::RunGameLoop()
 		 * Render
 		 */
 		SCREENMAN->Draw();
-
-		/* If we don't have focus, give up lots of CPU. */
-		// XXX: do this in DISPLAY EndFrame?
-		if( !HOOKS->AppHasFocus() )
-			usleep( 10000 );// give some time to other processes and threads
-#if defined(_WINDOWS)
-		/* In Windows, we want to give up some CPU for other threads.  Most OS's do
-		 * this more intelligently. */
-		else
-			usleep( 1000 );	// give some time to other processes and threads
-#endif
 	}
 
 	if( ChangeAppPri() )
diff --git a/stepmania/src/RageDisplay.cpp b/stepmania/src/RageDisplay.cpp
index f08f86b112..28c96d9fb3 100644
--- a/stepmania/src/RageDisplay.cpp
+++ b/stepmania/src/RageDisplay.cpp
@@ -11,6 +11,7 @@
 #include "RageSurface.h"
 #include "Preference.h"
 #include "LocalizedString.h"
+#include "arch/ArchHooks/ArchHooks.h"
 
 //
 // Statistics stuff
@@ -774,24 +775,33 @@ void RageDisplay::FrameLimitBeforeVsync( int iFPS )
 {
 	ASSERT( iFPS != 0 );
 
-	if( g_LastFrameEndedAt.IsZero() )
-		return;
+	int iDelayMicroseconds = 0;
+	if( g_fFrameLimitPercent.Get() > 0.0f && !g_LastFrameEndedAt.IsZero() )
+	{
+		float fFrameTime = g_LastFrameEndedAt.GetDeltaTime();
+		float fExpectedTime = 1.0f / iFPS;
 
-	if( g_fFrameLimitPercent.Get() == 0.0f )
-		return;
+		/* This is typically used to turn some of the delay that would normally
+		 * be waiting for vsync and turn it into a usleep, to make sure we give
+		 * up the CPU.  If we overshoot the sleep, then we'll miss the vsync,
+		 * so allow tweaking the amount of time we expect a frame to take.
+		 * Frame limiting is disabled by setting this to 0. */
+		fExpectedTime *= g_fFrameLimitPercent.Get();
+		float fExtraTime = fExpectedTime - fFrameTime;
 
-	float fFrameTime = g_LastFrameEndedAt.GetDeltaTime();
-	float fExpectedTime = 1.0f / iFPS;
+		iDelayMicroseconds = int(fExtraTime * 1000000);
+	}
 
-	/* This is typically used to turn some of the delay that would normally
-	 * be waiting for vsync and turn it into a usleep, to make sure we give
-	 * up the CPU.  If we overshoot the sleep, then we'll miss the vsync,
-	 * so allow tweaking the amount of time we expect a frame to take.
-	 * Frame limiting is disabled by setting this to 0. */
-	fExpectedTime *= g_fFrameLimitPercent.Get();
-	float fExtraTime = fExpectedTime - fFrameTime;
-	if( fExtraTime > 0 )
-		usleep( int(fExtraTime * 1000000) );
+	if( !HOOKS->AppHasFocus() )
+		iDelayMicroseconds = max( iDelayMicroseconds, 10000 ); // give some time to other processes and threads
+
+#if defined(_WINDOWS)
+	/* In Windows, always explicitly give up a minimum amount of CPU for other threads. */
+	iDelayMicroseconds = max( iDelayMicroseconds, 1000 );
+#endif
+
+	if( iDelayMicroseconds > 0 )
+		usleep( iDelayMicroseconds );
 }
 
 void RageDisplay::FrameLimitAfterVsync()