PSP: throttle the number of updateScreen() calls

svn-id: r43539

3 files changed, 11 insertions, 1 deletions

diff --git a/backends/platform/psp/osys_psp.cpp b/backends/platform/psp/osys_psp.cpp
index 566db3014b..5e461f45e0 100644
--- a/backends/platform/psp/osys_psp.cpp
+++ b/backends/platform/psp/osys_psp.cpp
@@ -75,7 +75,7 @@ const OSystem::GraphicsMode OSystem_PSP::s_supportedGraphicsModes[] = {
 };
 
 
-OSystem_PSP::OSystem_PSP() : _screenWidth(0), _screenHeight(0), _overlayWidth(0), _overlayHeight(0), _offscreen(0), _overlayBuffer(0), _overlayVisible(false), _shakePos(0), _mouseBuf(0), _prevButtons(0), _lastPadCheck(0), _padAccel(0), _mixer(0) {
+OSystem_PSP::OSystem_PSP() : _screenWidth(0), _screenHeight(0), _overlayWidth(0), _overlayHeight(0), _offscreen(0), _overlayBuffer(0), _overlayVisible(false), _shakePos(0), _lastScreenUpdate(0), _mouseBuf(0), _prevButtons(0), _lastPadCheck(0), _padAccel(0), _mixer(0) {
 
 	memset(_palette, 0, sizeof(_palette));
 
diff --git a/backends/platform/psp/osys_psp.h b/backends/platform/psp/osys_psp.h
index 310efdc7d4..94488a92ce 100644
--- a/backends/platform/psp/osys_psp.h
+++ b/backends/platform/psp/osys_psp.h
@@ -59,6 +59,7 @@ protected:
 	uint16  _palette[256];
 	bool	_overlayVisible;
 	uint32	_shakePos;
+	uint32	_lastScreenUpdate;
 
 	Graphics::Surface _framebuffer;
 
diff --git a/backends/platform/psp/osys_psp_gu.cpp b/backends/platform/psp/osys_psp_gu.cpp
index 0fb1b4aded..1c83aa4abf 100644
--- a/backends/platform/psp/osys_psp_gu.cpp
+++ b/backends/platform/psp/osys_psp_gu.cpp
@@ -38,6 +38,8 @@
 #define MOUSE_SIZE	128
 #define	KBD_DATA_SIZE	130560
 
+#define	MAX_FPS	30
+
 unsigned int __attribute__((aligned(16))) list[262144];
 unsigned short __attribute__((aligned(16))) clut256[256];
 unsigned short __attribute__((aligned(16))) mouseClut[256];
@@ -295,6 +297,13 @@ void OSystem_PSP_GU::copyRectToScreen(const byte *buf, int pitch, int x, int y,
 }
 
 void OSystem_PSP_GU::updateScreen() {
+	u32 now = getMillis();
+	if (now - _lastScreenUpdate < 1000 / MAX_FPS)
+		return;
+
+	_lastScreenUpdate = now;
+
+
 	sceGuStart(0,list);
 
 	sceGuClearColor(0xff000000);