From 9192d156d110f49cc4b6348b73c121886242767c Mon Sep 17 00:00:00 2001
From: BZLZHH <admin@bzlzhh.top>
Date: Sat, 1 Aug 2026 08:09:49 -0400
Subject: [PATCH] [Fix] (DirectVulkan): ReadPixels materializes pending clears
 before resolving the blit binding

ResolveColorBlitBinding cached a RenderbufferResource*/TextureResource*
(trackedLayout) before the pending-clear materialization step ran. For an
attachment that had never been part of any render pass yet (e.g. a
GL_NONE draw buffer slot read back via an explicit glReadBuffer), the
materialize call was the first thing to touch its resource, and creating
that entry in the UnorderedMap (FastSTL, open-addressing) can rehash and
invalidate every previously-taken pointer into the map - including the
one just cached. The read then saw a stale VK_IMAGE_LAYOUT_UNDEFINED and
silently bailed (via a compiled-out MGLOG_E in release builds), leaving
the client buffer untouched. Reordering so the clear is materialized
first, then the binding resolved, guarantees the pointer reflects the
final resource state. Fixes KHR-GL3{0,1,2,3}.draw_buffers.draw_buffers_1.
---
 .../DirectVulkan/Renderer/VulkanRenderer.cpp  | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/MobileGL/MG_Backend/DirectVulkan/Renderer/VulkanRenderer.cpp b/MobileGL/MG_Backend/DirectVulkan/Renderer/VulkanRenderer.cpp
index 976c9676..e41cd580 100644
--- a/MobileGL/MG_Backend/DirectVulkan/Renderer/VulkanRenderer.cpp
+++ b/MobileGL/MG_Backend/DirectVulkan/Renderer/VulkanRenderer.cpp
@@ -6982,11 +6982,14 @@ void main() {
         }
 
         const Bool readIsDefaultFbo = readFbo->IsDefaultFramebuffer();
-        BlitImageBinding srcBinding{};
-        if (!ResolveColorBlitBinding(*readFbo, true, m_imageIndexAcquired, m_swapchainObject, *m_textureManager,
-                                     *m_renderPassManager, srcBinding)) {
-            return;
-        }
+        // Materialize any pending clear on the read-buffer attachment BEFORE resolving the
+        // blit binding below: for a renderbuffer/texture that has never been part of any
+        // render pass yet (e.g. a GL_NONE draw buffer slot whose attachment is only ever
+        // touched via an explicit glReadBuffer), materializing lazily creates its backing
+        // Vulkan resource for the first time. UnorderedMap (FastSTL, open-addressing) may
+        // rehash on that insertion, invalidating any RenderbufferResource*/TextureResource*
+        // obtained beforehand - so ResolveColorBlitBinding's cached `trackedLayout` pointer
+        // must be taken AFTER this, never before it.
         if (!readIsDefaultFbo) {
             const auto& sourceAttachment = readFbo->GetAttachment(readFbo->GetReadBuffer());
             auto sourceTexture = sourceAttachment.GetTexture();
@@ -7004,6 +7007,12 @@ void main() {
             }
         }
 
+        BlitImageBinding srcBinding{};
+        if (!ResolveColorBlitBinding(*readFbo, true, m_imageIndexAcquired, m_swapchainObject, *m_textureManager,
+                                     *m_renderPassManager, srcBinding)) {
+            return;
+        }
+
         const VkImageLayout srcOriginalLayout = readIsDefaultFbo
             ? m_swapchainObject.GetImageLayout(m_imageIndexAcquired)
             : *srcBinding.trackedLayout;