Added Sending position field to ship; Fixed bug with unloading nil re…

…sources from ship; (#21)

cardinal/component/effect.go

@@ -34,6 +34,7 @@ type Effect struct {
 	Speed                 float64     `json:"speed"`
 	Position              [2]float64  `json:"position,omitempty"`
 	TargetPosition        *[2]float64 `json:"targetPosition,omitempty"`
+	SendingPosition       *[2]float64 `json:"sendingPosition,omitempty"`
 	BuildingTimeSeconds   int         `json:"buildingTimeSeconds,omitempty"`
 	BuildingTimeStartedAt uint64      `json:"buildingTimeStartedAt,omitempty"`
 }

cardinal/system/sail_ship.go

@@ -42,9 +42,12 @@ func SailShip(world cardinal.WorldContext) error {
 
 			if buildingComponent.Effect.Position == playerPosition.Island {
 				buildingComponent.Effect.TargetPosition = nil
+				buildingComponent.Effect.SendingPosition = nil
 				_ = unloadShip(world, buildingComponent.Effect)
 			} else if buildingComponent.Effect.Position == *buildingComponent.Effect.TargetPosition {
+				previousTargetPosition := buildingComponent.Effect.TargetPosition
 				buildingComponent.Effect.TargetPosition = &playerPosition.Island
+				buildingComponent.Effect.SendingPosition = previousTargetPosition
 				_ = lootShipwreck(world, buildingComponent.Effect)
 			}
 
@@ -106,6 +109,9 @@ func lootShipwreck(world cardinal.WorldContext, effect *comp.Effect) error {
 }
 
 func unloadShip(world cardinal.WorldContext, effect *comp.Effect) error {
+	if effect.LootResources == nil {
+		return nil
+	}
 	playerResourcesID, playerResources, _ := QueryPlayerComponent[comp.PlayerResources](
 		world,
 		effect.Player,

cardinal/system/start_sail_shipwreck_system.go

@@ -85,6 +85,7 @@ func createSailData(
 	}
 	shipyardEffect := shipyard.Effect
 	shipyardEffect.TargetPosition = &targetPlayerPosition.Shipwreck
+	shipyardEffect.SendingPosition = &playerPosition.Island
 	err := updateEffect(world, shipyardEntityID, shipyard.Effect)
 	if err != nil {
 		return err