From 92d3fc302acf3a41b914b48034e98a9d80f502a8 Mon Sep 17 00:00:00 2001
From: Skyth <19259897+blueskythlikesclouds@users.noreply.github.com>
Date: Tue, 18 Nov 2025 15:33:30 +0300
Subject: [PATCH] Fix buffer creation on old D3D12 runtimes.

---
 drivers/d3d12/rendering_device_driver_d3d12.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/d3d12/rendering_device_driver_d3d12.cpp b/drivers/d3d12/rendering_device_driver_d3d12.cpp
index 2ba7cb509cb2..56e10885b509 100644
--- a/drivers/d3d12/rendering_device_driver_d3d12.cpp
+++ b/drivers/d3d12/rendering_device_driver_d3d12.cpp
@@ -1059,6 +1059,11 @@ RDD::BufferID RenderingDeviceDriverD3D12::buffer_create(uint64_t p_size, BitFiel
 			if (p_usage.has_flag(BUFFER_USAGE_DYNAMIC_PERSISTENT_BIT)) {
 				allocation_desc.HeapType = dynamic_persistent_upload_heap;
 
+				// D3D12_HEAP_TYPE_UPLOAD mandates D3D12_RESOURCE_STATE_GENERIC_READ.
+				if (dynamic_persistent_upload_heap == D3D12_HEAP_TYPE_UPLOAD) {
+					initial_state = D3D12_RESOURCE_STATE_GENERIC_READ;
+				}
+
 				// We can't use STORAGE for write access, just for read.
 				resource_desc.Flags = resource_desc.Flags & ~D3D12_RESOURCE_FLAG_ALLOW_UNORDERED_ACCESS;
 			}