diff -r 18de2af03531 -r d3285aed65b3 src/context.c
--- a/src/context.c	Thu Mar 28 23:30:21 2024 +0100
+++ b/src/context.c	Fri Mar 29 00:03:25 2024 +0100
@@ -33,8 +33,16 @@
 #include <SDL2/SDL.h>
 #include <SDL2/SDL_ttf.h>
 
+#include <time.h>
+
 AscContext asc_context;
 
+static uint64_t asc_nanos(void) {
+    struct timespec ts;
+    clock_gettime(CLOCK_MONOTONIC, &ts);
+    return 1000000000ull*(uint64_t)ts.tv_sec + (uint64_t)ts.tv_nsec;
+}
+
 void asc_context_initialize(void) {
     if (asc_test_flag(asc_context.flags, ASC_FLAG_INITILIZED))
         return;
@@ -58,6 +66,7 @@
         }
     }
     SDL_ClearError();
+    asc_context.total_nanos = asc_nanos();
     asc_set_flag(&asc_context.flags, ASC_FLAG_INITILIZED);
     asc_dprintf("Ascension context initialized.");
 }
@@ -128,11 +137,13 @@
     }
 
     // compute frame time
-    static Uint32 ticks;
-    Uint32 ticks_elapsed = SDL_GetTicks() - ticks;
-    ticks = SDL_GetTicks();
-    asc_context.elapsed_millis = ticks_elapsed;
-    asc_context.elapsed = (float) ticks_elapsed / 1000.0f;
+    uint64_t frame_nanos, ns;
+    do {
+        ns = asc_nanos();
+        frame_nanos = ns - asc_context.total_nanos;
+    } while (frame_nanos == 0);
+    asc_context.frame_nanos = frame_nanos;
+    asc_context.total_nanos = ns;
 
     return !asc_test_flag(asc_context.flags, ASC_FLAG_QUIT);
 }