performance.c

   1 #include <time.h>
   2 #include <stdio.h> // TODO remove
   3 #include <stdbool.h>
   4
   5 typedef struct timespec Timepoint;
   6
   7 static Timepoint lastDisplayTime;
   8 static int frames = 0;
   9 static bool meteringEnabled = false;
  10
  11 void initPerformanceMetering() {
  12         if (clock_gettime(CLOCK_MONOTONIC, &lastDisplayTime) != 0) {
  13                 fprintf(stderr, "Clock read failed, performance metering unavailable\n");
  14         }
  15         else {
  16                 meteringEnabled = true;
  17         }
  18 }
  19
  20 void frameRendered() {
  21         if (meteringEnabled) {
  22                 ++frames;
  23                 Timepoint now;
  24
  25                 if (clock_gettime(CLOCK_MONOTONIC, &now) != 0) {
  26                         fprintf(stderr, "Clock read failed, stopping performance metering\n");
  27                         meteringEnabled = false;
  28                         return;
  29                 }
  30
  31                 time_t fullSeconds = now.tv_sec - lastDisplayTime.tv_sec;
  32                 if (now.tv_nsec < lastDisplayTime.tv_nsec) --fullSeconds;
  33
  34                 if (fullSeconds > 0) {
  35                         float seconds = (now.tv_nsec - lastDisplayTime.tv_nsec) / 1000000000.0f;
  36                         seconds += (float) (now.tv_sec - lastDisplayTime.tv_sec);
  37                         printf("frametime avg %.1f ms; fps avg %.f\n", (seconds / frames) * 1000.0f, (frames / seconds));
  38                         lastDisplayTime = now;
  39                         frames = 0;
  40                 }
  41         }
  42 }