frameskip, cleanups

[fceu.git] / drivers / pc / throttle.c

diff --git a/drivers/pc/throttle.c b/drivers/pc/throttle.c
index 91879ae..81cd916 100644 (file)
--- a/drivers/pc/throttle.c
+++ b/drivers/pc/throttle.c
@@ -2,6 +2,7 @@
 #include "main.h"
 #include "throttle.h"
 
+#if 0
 static uint64 tfreq;
 static uint64 desiredfps;
 
@@ -44,3 +45,66 @@ INLINE void SpeedThrottle(void)
   ltime+=tfreq/desiredfps;
 }
 
+#else
+
+extern uint8 PAL;
+extern int FSkip, FSkip_setting;
+static int usec_aim = 0, usec_done = 0;
+static int skip_count = 0;
+
+INLINE void SpeedThrottle(void)
+{
+       static struct timeval tv_prev;
+       struct timeval tv_now;
+       int delta_nom = PAL ? 19997 : 16639; // ~50.007, 19.997 ms/frame : ~60.1, 16.639 ms/frame
+
+
+       if (usec_done == 0) { // first time
+               usec_done = 1;
+               gettimeofday(&tv_prev, 0);
+               return;
+       }
+
+       gettimeofday(&tv_now, 0);
+
+       usec_aim += delta_nom;
+       if (tv_now.tv_sec != tv_prev.tv_sec)
+               usec_done += 1000000;
+       usec_done += tv_now.tv_usec - tv_prev.tv_usec;
+
+#ifdef FRAMESKIP
+       if (FSkip_setting >= 0)
+       {
+               if (skip_count >= FSkip_setting)
+                       skip_count = 0;
+               else {
+                       skip_count++;
+                       FSkip = 1;
+               }
+       }
+       else if (usec_done > usec_aim)
+       {
+               /* auto frameskip */
+               if (usec_done - usec_aim > 150000)
+                       usec_done = usec_aim = 0; // too much behind, try to recover..
+               FSkip = 1;
+               tv_prev = tv_now;
+               return;
+       }
+#endif
+
+       tv_prev = tv_now;
+       while (usec_done < usec_aim)
+       {
+               gettimeofday(&tv_now, 0);
+
+               if (tv_now.tv_sec != tv_prev.tv_sec)
+                       usec_done += 1000000;
+               usec_done += tv_now.tv_usec - tv_prev.tv_usec;
+               tv_prev = tv_now;
+       }
+       usec_done = usec_done - usec_aim + 1; // reset to prevent overflows
+       usec_aim = 0;
+}
+#endif
+