add time_step argument to systemInit

src/orbits.cpp

@@ -3,11 +3,10 @@
 
 
 const static uint ELLIPSE_VERT_COUNT = 256;
-const static uint DEFAULT_TIME_STEP = 1;
 
 
 system_2body
-systemInit(grav_body gb, orbital_elements el)
+systemInit(grav_body gb, orbital_elements el, float time_step)
 {
 	system_2body s = {0};
 	s.body = gb;
@@ -19,7 +18,7 @@ systemInit(grav_body gb, orbital_elements el)
 	s.orbital_period = orbitGetPeriod(s.ep.a, gb.mu);
 	s.r_apoapsis = s.ep.a - s.ep.c;
 	s.r_periapsis = 2 * s.ep.a - s.r_apoapsis;
-	s.time_step = DEFAULT_TIME_STEP;
+	s.time_step = time_step;
 
 	return s;
 }

src/orbits.h

@@ -72,8 +72,11 @@ struct system_2body
 };
 
 
+#define DEFAULT_TIME_STEP 1
 system_2body
-systemInit(grav_body gb, orbital_elements el);
+systemInit(grav_body gb,
+			orbital_elements el,
+			float time_step = DEFAULT_TIME_STEP);
 
 grav_body
 gravBodyInit(double mu, double r);