implement "orbit_phase_offset" command

src/commands.rs

@@ -254,6 +254,21 @@ pub fn load_defs(
                     continue;
                 }
             }
+            ["orbit_phase_offset", value] => {
+                if let Ok(value_float) = value.parse::<f64>() {
+                    let offset_radians = 2.0 * PI64 * value_float;
+                    if let Some(phase_radians) = state.orbit_phase {
+                        state.orbit_phase = Some(phase_radians + offset_radians);
+                    }
+                    else {
+                        state.orbit_phase = Some(offset_radians);
+                    }
+                }
+                else {
+                    error!("Can't parse float: {line}");
+                    continue;
+                }
+            }
             ["sphere", "yes"] => {
                 state.is_sphere = true;
             }
@@ -519,9 +534,11 @@ fn spawn_entities(
                 state.pos
             };
             if let Some(r) = state.orbit_distance {
-                let phase_radians: f64 = if let Some(phase_radians) = state.orbit_phase {
-                    phase_radians
-                } else if let Some(id) = &state.orbit_object_id {
+                let mut phase_radians = 0.0f64;
+                if let Some(phase) = state.orbit_phase {
+                    phase_radians += phase;
+                }
+                if let Some(id) = &state.orbit_object_id {
                     let mass = match id.as_str() {
                         "jupiter" => nature::JUPITER_MASS,
                         _ => {
@@ -530,16 +547,13 @@ fn spawn_entities(
                         }
                     };
                     let orbital_period = nature::simple_orbital_period(mass, r);
-                    if let Ok(epoch) = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH) {
+                    phase_radians += if let Ok(epoch) = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH) {
                         PI64 * 2.0 * (epoch.as_secs_f64() % orbital_period) / orbital_period
                     } else {
                         error!("Can't determine current time `{id}`");
                         0.0
-                    }
-                } else {
-                    error!("if state.orbit_distance is set, then either state.orbit_object_id or state.orbit_phase must be set as well.");
-                    continue;
-                };
+                    };
+                }
                 absolute_pos += nature::phase_dist_to_coords(phase_radians, r);
             }
             let scale = Vec3::splat(if state.is_sun {

src/data/defs.txt

@@ -122,7 +122,8 @@ actor 0 0 0 jupiter
 
 actor 0 593051 0 suitv2
     relativeto jupiter
-    orbit 224000e3 0.66
+    orbitaround jupiter 221900e3
+    orbit_phase_offset 0.003
     player yes
     id player
     scale 2