performance.c

   1 #ifndef _POSIX_C_SOURCE
   2 #define _POSIX_C_SOURCE 199309L
   3 #endif
   4
   5 #include <stdbool.h>
   6 #include <stdio.h> // TODO remove
   7 #include <time.h>
   8
   9 #include "logger.h"
  10
  11 typedef struct timespec Timepoint;
  12
  13 static Timepoint lastDisplayTime;
  14 static int frames = 0;
  15 static bool meteringEnabled = false;
  16
  17 void initPerformanceMetering() {
  18         if (clock_gettime(CLOCK_MONOTONIC, &lastDisplayTime) != 0) {
  19                 logWarning("Clock read failed, performance metering unavailable");
  20         }
  21         else {
  22                 meteringEnabled = true;
  23         }
  24 }
  25
  26 void frameRendered() {
  27         if (meteringEnabled) {
  28                 ++frames;
  29                 Timepoint now;
  30
  31                 if (clock_gettime(CLOCK_MONOTONIC, &now) != 0) {
  32                         logWarning("Clock read failed, stopping performance metering");
  33                         meteringEnabled = false;
  34                         return;
  35                 }
  36
  37                 time_t fullSeconds = now.tv_sec - lastDisplayTime.tv_sec;
  38                 if (now.tv_nsec < lastDisplayTime.tv_nsec) --fullSeconds;
  39
  40                 if (fullSeconds > 0) {
  41                         float seconds = (now.tv_nsec - lastDisplayTime.tv_nsec) / 1000000000.0f;
  42                         seconds += (float) (now.tv_sec - lastDisplayTime.tv_sec);
  43                         // This goes to STDOUT because it's, uh, temporary
  44                         printf("frametime avg %.1f ms; fps avg %.f\n", (seconds / frames) * 1000.0f, (frames / seconds));
  45                         lastDisplayTime = now;
  46                         frames = 0;
  47                 }
  48         }
  49 }