From 9a6a430768719ef19ee512b1558244b37fdee5d2 Mon Sep 17 00:00:00 2001
From: Kelsi <kelsihates2fa@gmail.com>
Date: Tue, 24 Mar 2026 13:05:27 -0700
Subject: [PATCH] fix: track render pass subpass mode to prevent ImGui
 secondary violation
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When parallel recording is active, the scene pass uses
VK_SUBPASS_CONTENTS_SECONDARY_COMMAND_BUFFERS. Post-processing paths
(FSR/FXAA) end the scene pass and begin a new INLINE render pass for
the swapchain output. ImGui rendering must use the correct mode —
secondary buffers for SECONDARY passes, direct calls for INLINE.

Previously the check used a static condition based on enabled features
(!fsr && !fsr2 && !fxaa && parallel), which could mismatch if a
feature was enabled but initialization failed. Replace with
endFrameInlineMode_ flag that tracks the actual current render pass
mode at runtime, eliminating the validation error
VUID-vkCmdDrawIndexed-commandBuffer-recording that caused intermittent
NVIDIA driver crashes.
---
 include/rendering/renderer.hpp |  1 +
 src/rendering/renderer.cpp     | 23 ++++++++++++++++-------
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/include/rendering/renderer.hpp b/include/rendering/renderer.hpp
index b53e87d1..80b33fe6 100644
--- a/include/rendering/renderer.hpp
+++ b/include/rendering/renderer.hpp
@@ -668,6 +668,7 @@ private:
     VkCommandBuffer secondaryCmds_[NUM_SECONDARIES][MAX_FRAMES] = {};
 
     bool parallelRecordingEnabled_ = false;  // set true after pools/buffers created
+    bool endFrameInlineMode_ = false;       // true when endFrame switched to INLINE render pass
     bool createSecondaryCommandResources();
     void destroySecondaryCommandResources();
     VkCommandBuffer beginSecondary(uint32_t secondaryIndex);
diff --git a/src/rendering/renderer.cpp b/src/rendering/renderer.cpp
index 7fd90840..801f28e2 100644
--- a/src/rendering/renderer.cpp
+++ b/src/rendering/renderer.cpp
@@ -1215,6 +1215,11 @@ void Renderer::beginFrame() {
 void Renderer::endFrame() {
     if (!vkCtx || currentCmd == VK_NULL_HANDLE) return;
 
+    // Track whether a post-processing path switched to an INLINE render pass.
+    // beginFrame() may have started the scene pass with SECONDARY_COMMAND_BUFFERS;
+    // post-proc paths end it and begin a new INLINE pass for the swapchain output.
+    endFrameInlineMode_ = false;
+
     if (fsr2_.enabled && fsr2_.sceneFramebuffer) {
         // End the off-screen scene render pass
         vkCmdEndRenderPass(currentCmd);
@@ -1297,7 +1302,7 @@ void Renderer::endFrame() {
         rpInfo.clearValueCount = msaaOn ? (vkCtx->getDepthResolveImageView() ? 4u : 3u) : 2u;
         rpInfo.pClearValues = clearValues;
 
-        vkCmdBeginRenderPass(currentCmd, &rpInfo, VK_SUBPASS_CONTENTS_INLINE);
+        endFrameInlineMode_ = true; vkCmdBeginRenderPass(currentCmd, &rpInfo, VK_SUBPASS_CONTENTS_INLINE);
 
         VkExtent2D ext = vkCtx->getSwapchainExtent();
         VkViewport vp{};
@@ -1434,18 +1439,22 @@ void Renderer::endFrame() {
         renderFSRUpscale();
     }
 
-    // ImGui rendering — must respect subpass contents mode
-    // Parallel recording only applies when no post-process pass is active.
-    if (!fsr_.enabled && !fsr2_.enabled && !fxaa_.enabled && parallelRecordingEnabled_) {
-        // Scene pass was begun with VK_SUBPASS_CONTENTS_SECONDARY_COMMAND_BUFFERS,
-        // so ImGui must be recorded into a secondary command buffer.
+    // ImGui rendering — must respect the subpass contents mode of the
+    // CURRENT render pass. Post-processing paths (FSR/FXAA) end the scene
+    // pass and begin a new INLINE pass; if none ran, we're still inside the
+    // scene pass which may be SECONDARY_COMMAND_BUFFERS when parallel recording
+    // is active. Track this via endFrameInlineMode_ (set true by any post-proc
+    // path that started an INLINE render pass).
+    if (parallelRecordingEnabled_ && !endFrameInlineMode_) {
+        // Still in the scene pass with SECONDARY_COMMAND_BUFFERS — record
+        // ImGui into a secondary command buffer.
         VkCommandBuffer imguiCmd = beginSecondary(SEC_IMGUI);
         setSecondaryViewportScissor(imguiCmd);
         ImGui_ImplVulkan_RenderDrawData(ImGui::GetDrawData(), imguiCmd);
         vkEndCommandBuffer(imguiCmd);
         vkCmdExecuteCommands(currentCmd, 1, &imguiCmd);
     } else {
-        // FSR swapchain pass uses INLINE mode; non-parallel also uses INLINE.
+        // INLINE render pass (post-process pass or non-parallel mode).
         ImGui_ImplVulkan_RenderDrawData(ImGui::GetDrawData(), currentCmd);
     }