From 2e5d7a734f4324fb01a6de2263eac8c010226289 Mon Sep 17 00:00:00 2001
From: JozsefA <jozsefaug@gmail.com>
Date: Thu, 25 Mar 2021 15:10:40 -0700
Subject: [PATCH] Fix ConcurrentModificationException preparing frame for
 rendering.

---
 .../render/ContraptionKineticRenderer.java    | 10 ++++----
 .../instancing/InstancedTileRenderer.java     | 24 +++++++++++--------
 2 files changed, 19 insertions(+), 15 deletions(-)

diff --git a/src/main/java/com/simibubi/create/content/contraptions/components/structureMovement/render/ContraptionKineticRenderer.java b/src/main/java/com/simibubi/create/content/contraptions/components/structureMovement/render/ContraptionKineticRenderer.java
index c6b3df6e6..20d0bc6a5 100644
--- a/src/main/java/com/simibubi/create/content/contraptions/components/structureMovement/render/ContraptionKineticRenderer.java
+++ b/src/main/java/com/simibubi/create/content/contraptions/components/structureMovement/render/ContraptionKineticRenderer.java
@@ -25,7 +25,7 @@ import java.util.ArrayList;
 
 public class ContraptionKineticRenderer extends InstancedTileRenderer<ContraptionProgram> {
 
-    protected ArrayList<com.simibubi.create.content.contraptions.components.structureMovement.render.ActorInstance> actors = new ArrayList<>();
+    protected ArrayList<ActorInstance> actors = new ArrayList<>();
 
     private final WeakReference<RenderedContraption> contraption;
 
@@ -46,25 +46,25 @@ public class ContraptionKineticRenderer extends InstancedTileRenderer<Contraptio
 
     @Override
     public void tick() {
-        actors.forEach(com.simibubi.create.content.contraptions.components.structureMovement.render.ActorInstance::tick);
+        actors.forEach(ActorInstance::tick);
     }
 
     @Override
     public void beginFrame(double cameraX, double cameraY, double cameraZ) {
         super.beginFrame(cameraX, cameraY, cameraZ);
 
-        actors.forEach(com.simibubi.create.content.contraptions.components.structureMovement.render.ActorInstance::beginFrame);
+        actors.forEach(ActorInstance::beginFrame);
     }
 
     @Nullable
-    public com.simibubi.create.content.contraptions.components.structureMovement.render.ActorInstance createActor(Pair<Template.BlockInfo, MovementContext> actor) {
+    public ActorInstance createActor(Pair<Template.BlockInfo, MovementContext> actor) {
         Template.BlockInfo blockInfo = actor.getLeft();
         MovementContext context = actor.getRight();
 
         MovementBehaviour movementBehaviour = AllMovementBehaviours.of(blockInfo.state);
 
         if (movementBehaviour != null && movementBehaviour.hasSpecialInstancedRendering()) {
-            com.simibubi.create.content.contraptions.components.structureMovement.render.ActorInstance instance = movementBehaviour.createInstance(this, context);
+            ActorInstance instance = movementBehaviour.createInstance(this, context);
 
             actors.add(instance);
 
diff --git a/src/main/java/com/simibubi/create/foundation/render/backend/instancing/InstancedTileRenderer.java b/src/main/java/com/simibubi/create/foundation/render/backend/instancing/InstancedTileRenderer.java
index ebb6f8a57..ba4592852 100644
--- a/src/main/java/com/simibubi/create/foundation/render/backend/instancing/InstancedTileRenderer.java
+++ b/src/main/java/com/simibubi/create/foundation/render/backend/instancing/InstancedTileRenderer.java
@@ -44,10 +44,7 @@ public abstract class InstancedTileRenderer<P extends BasicProgram> {
     }
 
     public void beginFrame(double cameraX, double cameraY, double cameraZ) {
-        if (queuedAdditions.size() > 0) {
-            queuedAdditions.forEach(this::addInternal);
-            queuedAdditions.clear();
-        }
+        processQueuedAdditions();
         if (dynamicInstances.size() > 0)
             dynamicInstances.values().forEach(IDynamicInstance::beginFrame);
     }
@@ -111,12 +108,6 @@ public abstract class InstancedTileRenderer<P extends BasicProgram> {
         }
     }
 
-    public <T extends TileEntity> void queueAdd(T tile) {
-        if (!Backend.canUseInstancing()) return;
-
-        queuedAdditions.add(tile);
-    }
-
     public <T extends TileEntity> void update(T tile) {
         if (!Backend.canUseInstancing()) return;
 
@@ -144,6 +135,19 @@ public abstract class InstancedTileRenderer<P extends BasicProgram> {
         }
     }
 
+    public synchronized <T extends TileEntity> void queueAdd(T tile) {
+        if (!Backend.canUseInstancing()) return;
+
+        queuedAdditions.add(tile);
+    }
+
+    protected synchronized void processQueuedAdditions() {
+        if (queuedAdditions.size() > 0) {
+            queuedAdditions.forEach(this::addInternal);
+            queuedAdditions.clear();
+        }
+    }
+
     private void addInternal(TileEntity tile) {
         getInstance(tile, true);
     }