From 55c371a081842fe7ecfec63b9283e67964062059 Mon Sep 17 00:00:00 2001
From: sammifs <samuel.sverker@gmail.com>
Date: Fri, 3 Apr 2026 19:32:25 +0200
Subject: [PATCH] Fix invalid swapchain semaphore reuse by making
 present-finish semaphores per swapchain image

Use a separate semaphore for each swapchain image instead of reusing
present-wait semaphores per frame in flight. Signal and present using
readyPresentSemaphores[imageIndex] so a semaphore is only reused after
its swapchain image has been reacquired.

Also rename renderFinishedSemaphores to readyPresentSemaphores for clarity.
---
 src/lve_swap_chain.cpp | 16 +++++++++++-----
 src/lve_swap_chain.hpp |  2 +-
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/src/lve_swap_chain.cpp b/src/lve_swap_chain.cpp
index fb55fdc..2bf4a0b 100644
--- a/src/lve_swap_chain.cpp
+++ b/src/lve_swap_chain.cpp
@@ -57,10 +57,12 @@ LveSwapChain::~LveSwapChain() {
 
   // cleanup synchronization objects
   for (size_t i = 0; i < MAX_FRAMES_IN_FLIGHT; i++) {
-    vkDestroySemaphore(device.device(), renderFinishedSemaphores[i], nullptr);
     vkDestroySemaphore(device.device(), imageAvailableSemaphores[i], nullptr);
     vkDestroyFence(device.device(), inFlightFences[i], nullptr);
   }
+  for (size_t i = 0; i < imageCount(); i++) {
+    vkDestroySemaphore(device.device(), readyPresentSemaphores[i], nullptr);
+  }
 }
 
 VkResult LveSwapChain::acquireNextImage(uint32_t *imageIndex) {
@@ -100,7 +102,7 @@ VkResult LveSwapChain::submitCommandBuffers(const VkCommandBuffer *buffers, uint
   submitInfo.commandBufferCount = 1;
   submitInfo.pCommandBuffers = buffers;
 
-  VkSemaphore signalSemaphores[] = {renderFinishedSemaphores[currentFrame]};
+  VkSemaphore signalSemaphores[] = {readyPresentSemaphores[*imageIndex]};
   submitInfo.signalSemaphoreCount = 1;
   submitInfo.pSignalSemaphores = signalSemaphores;
 
@@ -348,7 +350,7 @@ void LveSwapChain::createDepthResources() {
 
 void LveSwapChain::createSyncObjects() {
   imageAvailableSemaphores.resize(MAX_FRAMES_IN_FLIGHT);
-  renderFinishedSemaphores.resize(MAX_FRAMES_IN_FLIGHT);
+  readyPresentSemaphores.resize(imageCount());
   inFlightFences.resize(MAX_FRAMES_IN_FLIGHT);
   imagesInFlight.resize(imageCount(), VK_NULL_HANDLE);
 
@@ -362,12 +364,16 @@ void LveSwapChain::createSyncObjects() {
   for (size_t i = 0; i < MAX_FRAMES_IN_FLIGHT; i++) {
     if (vkCreateSemaphore(device.device(), &semaphoreInfo, nullptr, &imageAvailableSemaphores[i]) !=
             VK_SUCCESS ||
-        vkCreateSemaphore(device.device(), &semaphoreInfo, nullptr, &renderFinishedSemaphores[i]) !=
-            VK_SUCCESS ||
         vkCreateFence(device.device(), &fenceInfo, nullptr, &inFlightFences[i]) != VK_SUCCESS) {
       throw std::runtime_error("failed to create synchronization objects for a frame!");
     }
   }
+  for (size_t i = 0; i < imageCount(); i++) {
+    if (vkCreateSemaphore(device.device(), &semaphoreInfo, nullptr, &readyPresentSemaphores[i]) !=
+        VK_SUCCESS) {
+      throw std::runtime_error("failed to create synchronization objects for a frame!");
+    }
+  }
 }
 
 VkSurfaceFormatKHR LveSwapChain::chooseSwapSurfaceFormat(
diff --git a/src/lve_swap_chain.hpp b/src/lve_swap_chain.hpp
index 0a1cb63..b7e574c 100644
--- a/src/lve_swap_chain.hpp
+++ b/src/lve_swap_chain.hpp
@@ -83,7 +83,7 @@ class LveSwapChain {
   std::shared_ptr<LveSwapChain> oldSwapChain;
 
   std::vector<VkSemaphore> imageAvailableSemaphores;
-  std::vector<VkSemaphore> renderFinishedSemaphores;
+  std::vector<VkSemaphore> readyPresentSemaphores;
   std::vector<VkFence> inFlightFences;
   std::vector<VkFence> imagesInFlight;
   size_t currentFrame = 0;