From 2568178b426a1c0b22551e9c4cf338a4f8456de0 Mon Sep 17 00:00:00 2001
From: Relintai <relintai@protonmail.com>
Date: Wed, 25 Aug 2021 17:24:25 +0200
Subject: [PATCH] Only call initial_setup_default on the main thread, and
 document that shader duplication can crash if done from a different thread.
 Removed the material mutex from the prop cache as it's not needed anymore.

---
 material_cache/prop_material_cache.cpp |  2 ++
 prop_instance_merger.cpp               | 16 +++++++++++++++-
 prop_instance_prop_job.cpp             |  4 +++-
 singleton/prop_cache.cpp               |  4 ----
 singleton/prop_cache.h                 |  2 --
 tiled_wall/tiled_wall.cpp              |  1 +
 6 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/material_cache/prop_material_cache.cpp b/material_cache/prop_material_cache.cpp
index a428d20..270beff 100644
--- a/material_cache/prop_material_cache.cpp
+++ b/material_cache/prop_material_cache.cpp
@@ -282,6 +282,8 @@ void PropMaterialCache::refresh_rects() {
 }
 
 void PropMaterialCache::initial_setup_default() {
+	//Note: call only on the main thread! Shader->duplicate() can crash if done from an another thread!
+
 	PropCache *pc = PropCache::get_singleton();
 
 	pc->ensure_materials_loaded();
diff --git a/prop_instance_merger.cpp b/prop_instance_merger.cpp
index c503803..03a1aea 100644
--- a/prop_instance_merger.cpp
+++ b/prop_instance_merger.cpp
@@ -533,6 +533,21 @@ void PropInstanceMerger::_build() {
 
 	Ref<PropMaterialCache> cache = PropCache::get_singleton()->material_cache_get(_prop_data);
 
+	if (!cache->get_initialized()) {
+		//lock it!
+		cache->mutex_lock();
+
+		//check again, this thread might have gotten here after an another one already did the initialization!
+		//this check might not be needed here
+		if (!cache->get_initialized()) {
+			//this will set up materials, and settings
+			//needs to be called from the main thread!
+			cache->initial_setup_default();
+		}
+
+		cache->mutex_unlock();
+	}
+
 	_job->set_material_cache(cache);
 
 	prop_preprocess(Transform(), _prop_data);
@@ -588,7 +603,6 @@ void PropInstanceMerger::_prop_preprocess(Transform transform, const Ref<PropDat
 		Ref<PropDataTiledWall> tiled_wall_data = e;
 
 		if (tiled_wall_data.is_valid()) {
-
 			_job->add_tiled_wall(tiled_wall_data, t);
 
 			if (tiled_wall_data->get_collision()) {
diff --git a/prop_instance_prop_job.cpp b/prop_instance_prop_job.cpp
index 7165fc3..9ab9512 100644
--- a/prop_instance_prop_job.cpp
+++ b/prop_instance_prop_job.cpp
@@ -267,7 +267,9 @@ void PropInstancePropJob::phase_setup_cache() {
 			//check again, this thread might have gotten here after an another one already did the initialization!
 			if (!_material_cache->get_initialized()) {
 				//this will set up materials, and settings
-				_material_cache->initial_setup_default();
+				//Can only be called from the main thread!
+				//Merger calls this
+				//_material_cache->initial_setup_default();
 
 				_material_cache->prop_add_textures(_prop_instace->get_prop_data());
 
diff --git a/singleton/prop_cache.cpp b/singleton/prop_cache.cpp
index 06166e9..482559a 100644
--- a/singleton/prop_cache.cpp
+++ b/singleton/prop_cache.cpp
@@ -170,13 +170,9 @@ void PropCache::materials_load() {
 }
 
 void PropCache::ensure_materials_loaded() {
-	_material_mutex.lock();
-
 	if (_materials.size() != _material_paths.size()) {
 		materials_load();
 	}
-
-	_material_mutex.unlock();
 }
 
 Vector<Variant> PropCache::materials_get() {
diff --git a/singleton/prop_cache.h b/singleton/prop_cache.h
index 9a1b685..e588c91 100644
--- a/singleton/prop_cache.h
+++ b/singleton/prop_cache.h
@@ -122,8 +122,6 @@ protected:
 	Mutex _tiled_wall_material_cache_mutex;
 	Mutex _custom_keyed_material_cache_mutex;
 
-	Mutex _material_mutex;
-
 #ifdef TEXTURE_PACKER_PRESENT
 	int _texture_flags;
 	int _max_atlas_size;
diff --git a/tiled_wall/tiled_wall.cpp b/tiled_wall/tiled_wall.cpp
index 765d96b..223bcc1 100644
--- a/tiled_wall/tiled_wall.cpp
+++ b/tiled_wall/tiled_wall.cpp
@@ -155,6 +155,7 @@ void TiledWall::refresh() {
 
 		//An anouther thread could have initialized it before wo got the mutex!
 		if (!_cache->get_initialized()) {
+			//can only be called from the main thread!
 			_cache->initial_setup_default();
 
 			_data->setup_cache(_cache);