Fix race condition while loading lights

src/graphics/gfxman.cpp

@@ -114,7 +114,7 @@ void GraphicsManager::removeLight(Light *light) {
 	if (!_renderer)
 		return;
 
-	_renderer->addLight(light);
+	_renderer->removeLight(light);
 }
 
 TexturePtr GraphicsManager::createTexture(ImageDecoder &&decoder, const std::string &label) {

src/graphics/opengl/renderer.cpp

@@ -502,6 +502,9 @@ void Renderer::drawWorld(const std::string &stage) {
 void Renderer::drawLights() {
 	pushDebug("Draw Lights");
 
+	// flush any new additions or removals
+	flushLights();
+
 	auto stencilProgram = getProgram("deferredlight", "render_stencil", 0);
 	auto pointlightProgram = getProgram("deferredlight", "pointlight", 0);
 

src/graphics/renderer.cpp

@@ -112,12 +112,29 @@ void Graphics::Renderer::removeGUIElement(Graphics::GUIElement *gui) {
 }
 
 void Graphics::Renderer::addLight(Graphics::Light *light) {
-	_lights.emplace_back(light);
+	_light_queues_mutex.lock();
+	_light_add_queue.push(light);
+	_light_queues_mutex.unlock();
 }
 
 void Graphics::Renderer::removeLight(Graphics::Light *light) {
-	const auto iter = std::remove(_lights.begin(), _lights.end(), light);
-	_lights.erase(iter);
+	_light_queues_mutex.lock();
+	_light_remove_queue.push(light);
+	_light_queues_mutex.unlock();
+}
+
+void Graphics::Renderer::flushLights() {
+	_light_queues_mutex.lock();
+	while (!_light_add_queue.empty()) {
+		_lights.push_back(_light_add_queue.front());
+		_light_add_queue.pop();
+	}
+	while (!_light_remove_queue.empty()) {
+		const auto iter = std::remove(_lights.begin(), _lights.end(), _light_remove_queue.front());
+		_lights.erase(iter);
+		_light_remove_queue.pop();
+	}
+	_light_queues_mutex.unlock();
 }
 
 void Graphics::Renderer::setCamera(Graphics::Camera &camera) {

src/graphics/renderer.h

@@ -21,6 +21,8 @@
 #ifndef AWE_RENDERER_H
 #define AWE_RENDERER_H
 
+#include <mutex>
+#include <queue>
 #include <vector>
 
 #include "src/common/frustrum.h"
@@ -54,6 +56,7 @@ class Renderer {
 	void removeGUIElement(GUIElement *gui);
 	void addLight(Light *light);
 	void removeLight(Light *light);
+	void flushLights();
 
 	void setCamera(Camera &camera);
 
@@ -158,6 +161,9 @@ class Renderer {
 	std::vector<ImGuiElement *> _imguiElements;
 	std::vector<GUIElement *> _guiElements;
 	std::vector<Light *> _lights;
+	std::queue<Light *> _light_add_queue;
+	std::queue<Light *> _light_remove_queue;
+	std::mutex _light_queues_mutex;
 };
 
 } // End of namespace Graphics