Fix time and subprojects

Moved SDL3 to subprojects.
Fixed time calculation.

Signed-off-by: Piotr Krygier <piotrkrygier@everyonecancode.xyz>

utilities/src/time_utils.c

@@ -5,11 +5,14 @@
 #include "errors_common.h"
 
 #define NS_TO_S(time) (time/1000000000)
+float g_time = 0.0f;
+float g_dt = 0.0f;
 double g_last_time = 0.0;
 
 rse_err_t time_init(void)
 {
     g_last_time = NS_TO_S((double)SDL_GetTicksNS());
+    g_time = g_last_time;
 
     return RSE_ERROR_NO_ERROR;
 }
@@ -21,13 +24,12 @@ double time_get_sec_from_start(void)
 
 void time_update(void)
 {
-    g_last_time = NS_TO_S((double)SDL_GetTicksNS());
+    g_last_time = g_time;
+    g_time = NS_TO_S((double)SDL_GetTicksNS());
+    g_dt = g_time - g_last_time;
 }
 
 double time_get_dt(void)
 {
-    float time = NS_TO_S((double)SDL_GetTicksNS());
-    float dt = time - g_last_time;
-
-    return dt;
+    return g_dt;
 }