performance.c

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