vcs.maemo.org Git - drnoksnes/blob - frame_skip.cpp

   1 #include <unistd.h>
   2 #include <sys/time.h>
   3 #include <time.h>
   4 #include <math.h>
   5 #include "frame_skip.h"
   6 #include "memmap.h"
   7
   8 #ifndef uclock_t
   9 #define uclock_t unsigned int
  10 #endif
  11
  12 #define TICKS_PER_SEC 1000000UL
  13 //#define CPU_FPS 60
  14 static int CPU_FPS=60;
  15 static uclock_t F;
  16
  17 #define MAX_FRAMESKIP 10
  18
  19
  20 static char init_frame_skip = 1;
  21 char skip_next_frame = 0;
  22 static struct timeval init_tv = { 0, 0 };
  23
  24
  25 void reset_frame_skip(void)
  26 {
  27         //static Uint8 init=0;
  28
  29         init_tv.tv_usec = 0;
  30         init_tv.tv_sec = 0;
  31         skip_next_frame = 0;
  32         init_frame_skip = 1;
  33         CPU_FPS=Memory.ROMFramesPerSecond;
  34
  35         F = (uclock_t) ((double) TICKS_PER_SEC / CPU_FPS);
  36 }
  37
  38 uclock_t get_ticks(void)
  39 {
  40         struct timeval tv;
  41
  42         gettimeofday(&tv, 0);
  43         if (init_tv.tv_sec == 0)
  44                 init_tv = tv;
  45         return (tv.tv_sec - init_tv.tv_sec) * TICKS_PER_SEC + tv.tv_usec -
  46                 init_tv.tv_usec;
  47
  48
  49 }
  50
  51 int frame_skip(void)
  52 {
  53         static int f2skip;
  54         static uclock_t sec = 0;
  55         static uclock_t rfd;
  56         static uclock_t target;
  57         static int nbFrame = 0;
  58         static int skpFrm = 0;
  59
  60         if (init_frame_skip) {
  61                 init_frame_skip = 0;
  62                 target = get_ticks();
  63                 nbFrame = 0;
  64                 //f2skip=0;
  65                 //skpFrm=0;
  66                 sec = 0;
  67                 return 0;
  68         }
  69
  70         target += F;
  71         if (f2skip > 0) {
  72                 f2skip--;
  73                 skpFrm++;
  74                 return 1;
  75         } else
  76                 skpFrm = 0;
  77
  78
  79         rfd = get_ticks();
  80
  81         if (rfd < target && f2skip == 0) {
  82                 while (get_ticks() < target);
  83         } else {
  84                 f2skip = (rfd - target) / (double) F;
  85                 if (f2skip > MAX_FRAMESKIP) {
  86                         f2skip = MAX_FRAMESKIP;
  87                         reset_frame_skip();
  88                 }
  89                 // printf("Skip %d frame(s) %lu %lu\n",f2skip,target,rfd);
  90         }
  91
  92
  93         nbFrame++;
  94         if (get_ticks() - sec >= TICKS_PER_SEC) {
  95                 nbFrame = 0;
  96                 sec = get_ticks();
  97         }
  98         return 0;
  99 }