From db0d07ed133f8bff372d3d6cc1570bde83ee4131 Mon Sep 17 00:00:00 2001
From: Supakorn 'Jamie' Rassameemasmuang <jamievlin@outlook.com>
Date: Sun, 31 Dec 2023 21:43:49 -0700
Subject: [PATCH] VK: Use thread safe queue for export signaling.

---
 include/vkrender.h | 11 ++++++++++-
 src/vkrender.cc    | 47 ++++++++++++++++++++++++++++++++++++++++------
 2 files changed, 51 insertions(+), 7 deletions(-)

diff --git a/include/vkrender.h b/include/vkrender.h
index 4568db6f9..a10bde18c 100644
--- a/include/vkrender.h
+++ b/include/vkrender.h
@@ -41,6 +41,8 @@
 #include "triple.h"
 #include "seconds.h"
 #include "statistics.h"
+#include "ThreadSafeQueue.h"
+#include "vkRenderMessages.h"
 
 namespace camp
 {
@@ -379,6 +381,11 @@ class AsyVkRender
   DrawMode mode = DRAWMODE_NORMAL;
   std::string title = "";
 
+  /**
+   * @remark Main thread is the consumer, other thread is the sender of messages;
+   */
+   ThreadSafeQueue<VulkanRendererMessage> messageQueue;
+
 #ifdef HAVE_PTHREAD
   pthread_t mainthread;
 
@@ -928,9 +935,10 @@ class AsyVkRender
 
   void nextFrame();
   void display();
-  void poll();
+  optional<VulkanRendererMessage> poll();
   void mainLoop();
   void cleanup();
+  void processMessages(VulkanRendererMessage const& msg);
 
   void idleFunc(std::function<void()> f);
   void idle();
@@ -938,6 +946,7 @@ class AsyVkRender
   // user controls
   static void exportHandler(int=0);
   void Export(int imageIndex);
+  bool readyForExport=false;
   void quit();
 
   double spinStep();
diff --git a/src/vkrender.cc b/src/vkrender.cc
index 1cead03fb..328a88b25 100644
--- a/src/vkrender.cc
+++ b/src/vkrender.cc
@@ -6,6 +6,7 @@
 
 #include <chrono>
 #include <thread>
+#include "ThreadSafeQueue.h"
 
 #define SHADER_DIRECTORY "shaders/"
 #define VALIDATION_LAYER "VK_LAYER_KHRONOS_validation"
@@ -3860,7 +3861,7 @@ void AsyVkRender::display()
   }
 }
 
-void AsyVkRender::poll()
+optional<VulkanRendererMessage> AsyVkRender::poll()
 {
   if (View) {
     if (glfwWindowShouldClose(window)) {
@@ -3876,14 +3877,38 @@ void AsyVkRender::poll()
   if (View) {
     glfwPollEvents();
   }
+
+  return messageQueue.dequeue();
+}
+
+void AsyVkRender::processMessages(VulkanRendererMessage const& msg)
+{
+  switch (msg)
+  {
+    case exportRender: {
+      if (readyForExport)
+      {
+        readyForExport= false;
+        exportHandler(0);
+      }
+    }
+    break;
+    default:
+      break;
+  }
 }
 
 void AsyVkRender::mainLoop()
 {
   int nFrames = 0;
 
-  while (poll(), true) {
-
+  while (true) {
+    auto const message = poll();
+    if (message.has_value())
+    {
+      processMessages(*message);
+    }
+    
     if (redraw || queueExport) {
       redraw = false;
       display();
@@ -3899,18 +3924,28 @@ void AsyVkRender::mainLoop()
   }
 
   vkDeviceWaitIdle(*device);
-
+  
   if(!View) {
     if(vkthread) {
       if(havewindow) {
+        // from where can this thread be called?
+        // signals to the main thread to start exporting
         readyAfterExport=true;
 #ifdef HAVE_PTHREAD
-        pthread_kill(mainthread,SIGUSR1);
+        if (pthread_equal(pthread_self(), this->mainthread))
+        {
+          exportHandler();
+        }
+        else
+        {
+          messageQueue.enqueue(exportRender);
+        }
 #endif
       } else {
+        // from main thread
         initialized=true;
+        readyForExport=true;
         readyAfterExport=true;
-        Signal(SIGUSR1,exportHandler);
         exportHandler();
       }
     } else {