add gametime

src/game/gametime.h

@@ -0,0 +1,31 @@
+#pragma once
+
+#include <time.h>
+
+typedef struct {
+    struct timespec ts; // stores the time at the current update
+    float timescale;    // multiplier for the time calculation, default value is 1.0
+    float deltatime;    // the time that it took between updates
+} gametime;
+
+// initializes the gametime struct
+static inline gametime gametime_new(void) {
+    return (gametime){
+        {0},
+        1.0F,
+        0.0F,
+    };
+}
+
+// updates the internal variables
+static inline void gametime_update(gametime* gt) {
+    struct timespec ts;
+    timespec_get(&ts, TIME_UTC);
+    gt->deltatime = ((double)(ts.tv_nsec - gt->ts.tv_nsec) * 1e-9) * gt->timescale;
+    gt->ts = ts;
+}
+
+// gets how many times the
+static inline float gametime_get_ups(gametime* gt) {
+    return 1.0F / gt->deltatime;
+}