Implemented a more efficient frameskip support, skipping frames at GPU level, which is loads faster.

It only works for Windows port atm, to make it work in the other ports :
call NDS_SkipFrame with param : true = skip the current frame, false = render the current frame.

desmume/src/NDSSystem.cpp

@@ -1010,6 +1010,10 @@ int NDS_LoadFirmware(const char *filename)
 	return i;
 }
 
+bool skipThisFrame = false;
+
+void NDS_SkipFrame(bool skip) { skipThisFrame = skip; }
+
 #define INDEX(i) ((((i)>>16)&0xFF0)|(((i)>>4)&0xF))
 
 
@@ -1114,9 +1118,12 @@ u32 NDS_exec(s32 nb)
 				NDS_ARM7HBlankInt();
 
 				if(nds.VCount<192)
+				{
+					if(!skipThisFrame)
 					{
 						GPU_ligne(&MainScreen, nds.VCount);
 						GPU_ligne(&SubScreen, nds.VCount);
+					}
 
 					if(MMU.DMAStartTime[0][0] == 2)
 						MMU_doDMA<ARMCPU_ARM9>(0);
@@ -1226,7 +1233,8 @@ u32 NDS_exec(s32 nb)
 					if(MMU.DMAStartTime[1][3] == 1)
 						MMU_doDMA<ARMCPU_ARM7>(3);
 				}
-				else if(nds.VCount==215) {
+				else if(nds.VCount==215)
+				{
 					gfx3d_VBlankEndSignal();
 				}
 				else if(nds.VCount==263)

desmume/src/NDSSystem.h

@@ -210,6 +210,8 @@ int NDS_WriteBMP(const char *filename);
 int NDS_LoadFirmware(const char *filename);
 int NDS_CreateDummyFirmware( struct NDS_fw_config_data *user_settings);
 
+void NDS_SkipFrame(bool skip);
+
 template<bool FORCE>
 u32 NDS_exec(s32 nb);
 

desmume/src/windows/main.cpp

@@ -971,8 +971,8 @@ DWORD WINAPI run()
 				DRV_AviSoundUpdate(SPU_core->outbuf,spu_core_samples);
 			   DRV_AviVideoUpdate((u16*)GPU_screen);
 
-               if (!skipnextframe)
-               {
+           //    if (!skipnextframe)
+            //   {
 				   input->process();
 
 				 if (FpsDisplay) osd->addFixed(0, 5, "%02d Fps", fps);
@@ -1002,10 +1002,15 @@ DWORD WINAPI run()
 					 SetWindowText(hwnd, txt);
 				  }
 
+			   if(!skipnextframe)
+			   {
+
                   framesskipped = 0;
 
                   if (framestoskip > 0)
                      skipnextframe = 1;
+
+				  NDS_SkipFrame(false);
                }
                else
                {
@@ -1017,6 +1022,8 @@ DWORD WINAPI run()
                      skipnextframe = 1;
 
                   framesskipped++;
+
+				  NDS_SkipFrame(true);
                }
 				
 			   while(SpeedThrottle())