grounditems/Lootbeam: handle loading models correctly

models are streamed over js5 so loadModel can return null until it is
downloaded

runelite-api/src/main/java/net/runelite/api/Client.java

@@ -1057,7 +1057,9 @@ public interface Client extends GameEngine
 	 * Loads a model from the cache
 	 *
 	 * @param id the ID of the model
+	 * @return the model or null if it is loading or nonexistent
 	 */
+	@Nullable
 	Model loadModel(int id);
 
 	/**
@@ -1066,7 +1068,9 @@ public interface Client extends GameEngine
 	 * @param id the ID of the model
 	 * @param colorToFind array of hsl color values to find in the model to replace
 	 * @param colorToReplace array of hsl color values to replace in the model
+	 * @return the model or null if it is loading or nonexistent
 	 */
+	@Nullable
 	Model loadModel(int id, short[] colorToFind, short[] colorToReplace);
 
 	/**

runelite-client/src/main/java/net/runelite/client/plugins/grounditems/GroundItemsPlugin.java

@@ -800,7 +800,7 @@ public class GroundItemsPlugin extends Plugin
 		Lootbeam lootbeam = lootbeams.get(worldPoint);
 		if (lootbeam == null)
 		{
-			lootbeam = new Lootbeam(client, worldPoint, color);
+			lootbeam = new Lootbeam(client, clientThread, worldPoint, color);
 			lootbeams.put(worldPoint, lootbeam);
 		}
 		else

runelite-client/src/main/java/net/runelite/client/plugins/grounditems/Lootbeam.java

@@ -27,10 +27,12 @@ package net.runelite.client.plugins.grounditems;
 import net.runelite.api.AnimationID;
 import net.runelite.api.Client;
 import net.runelite.api.JagexColor;
+import net.runelite.api.Model;
 import net.runelite.api.RuneLiteObject;
 import net.runelite.api.coords.LocalPoint;
 import net.runelite.api.coords.WorldPoint;
 import java.awt.Color;
+import net.runelite.client.callback.ClientThread;
 
 class Lootbeam
 {
@@ -39,11 +41,13 @@ class Lootbeam
 
 	private final RuneLiteObject runeLiteObject;
 	private final Client client;
+	private final ClientThread clientThread;
 	private Color color;
 
-	public Lootbeam(Client client, WorldPoint worldPoint, Color color)
+	public Lootbeam(Client client, ClientThread clientThread, WorldPoint worldPoint, Color color)
 	{
 		this.client = client;
+		this.clientThread = clientThread;
 		runeLiteObject = client.createRuneLiteObject();
 
 		setColor(color);
@@ -64,11 +68,21 @@ class Lootbeam
 		}
 
 		this.color = color;
-		runeLiteObject.setModel(client.loadModel(
-			RAID_LIGHT_MODEL,
-			new short[]{RAID_LIGHT_FIND_COLOR},
-			new short[]{JagexColor.rgbToHSL(color.getRGB(), 1.0d)}
-		));
+		clientThread.invoke(() ->
+		{
+			Model m = client.loadModel(
+				RAID_LIGHT_MODEL,
+				new short[]{RAID_LIGHT_FIND_COLOR},
+				new short[]{JagexColor.rgbToHSL(color.getRGB(), 1.0d)}
+			);
+			if (m == null)
+			{
+				return false;
+			}
+
+			runeLiteObject.setModel(m);
+			return true;
+		});
 	}
 
 	public void remove()