drivers/gp2x/throttle.c

   1 #include <sys/time.h>
   2 #include "main.h"
   3 #include "gp2x.h"
   4 #include "minimal.h"
   5 #include "throttle.h"
   6
   7
   8 extern uint8 PAL;
   9 extern int FSkip;
  10 static int skip_count = 0;
  11 static struct timeval tv_prev;
  12
  13 void RefreshThrottleFPS(void)
  14 {
  15         skip_count = 0;
  16         if (Settings.perfect_vsync)
  17         {
  18                 gp2x_video_wait_vsync();
  19         }
  20         gettimeofday(&tv_prev, 0);
  21 }
  22
  23 #define tvdiff(tv1, tv2) \
  24         ((tv1.tv_sec - tv2.tv_sec) * 1000000 + tv1.tv_usec - tv2.tv_usec)
  25
  26 #define tvadd(tv, usec) { \
  27         tv.tv_usec += usec; \
  28         if (tv.tv_usec >= 1000000) { \
  29                 tv.tv_sec += 1; \
  30                 tv.tv_usec -= 1000000; \
  31         } \
  32 }
  33
  34 #define tvsub(tv, usec) { \
  35         tv.tv_usec -= usec; \
  36         if (tv.tv_usec < 0) { \
  37                 tv.tv_sec -= 1; \
  38                 tv.tv_usec += 1000000; \
  39         } \
  40 }
  41
  42 static void wait_to(struct timeval *tv_aim)
  43 {
  44         struct timeval tv_now;
  45         int diff;
  46
  47         do
  48         {
  49                 gettimeofday(&tv_now, 0);
  50                 diff = tvdiff((*tv_aim), tv_now);
  51         }
  52         while (diff > 0);
  53 }
  54
  55 #include <stdio.h>
  56 void SpeedThrottle(void)
  57 {
  58         struct timeval tv_now, tv_aim;
  59         int tdiff;
  60
  61         tv_aim = tv_prev;
  62         tvadd(tv_aim, PAL ? 19997 : 16639); // ~50.007, 19.997 ms/frame : ~60.1, 16.639 ms/frame
  63
  64         gettimeofday(&tv_now, 0);
  65         tdiff = tvdiff(tv_now, tv_aim);
  66
  67 #ifdef FRAMESKIP
  68         if (Settings.frameskip >= 0)
  69         {
  70                 if (skip_count >= Settings.frameskip)
  71                         skip_count = 0;
  72                 else {
  73                         skip_count++;
  74                         FSkip = 1;
  75                 }
  76         }
  77         else if (tdiff > 0)
  78         {
  79                 /* auto frameskip */
  80                 tv_prev = tv_now;
  81                 if (tdiff < 1024*16)    // limit frameskip
  82                 {
  83                         FSkip = 1;
  84                         tvsub(tv_prev, tdiff);
  85                 }
  86                 return;
  87         }
  88 #endif
  89
  90         /* throttle */
  91         if (tdiff < 0)
  92         {
  93                 if (Settings.perfect_vsync)
  94                 {
  95                         if (tdiff <= (PAL ? 19997/2 : 16639/2))
  96                         {
  97                                 struct timeval tv_tmp = tv_aim;
  98                                 tvsub(tv_tmp, 5000);
  99                                 wait_to(&tv_tmp);
 100                         }
 101                         gp2x_video_wait_vsync();
 102                         gettimeofday(&tv_prev, 0);
 103                         return;
 104                 }
 105                 else
 106                 {
 107                         wait_to(&tv_aim);
 108                 }
 109         }
 110
 111         tv_prev = tv_aim;
 112 }
 113