From f6e0ae87fdfecbadb5c1e36c55d66a744187a3cd Mon Sep 17 00:00:00 2001
From: mchughalex <25671999+mchughalex@users.noreply.github.com>
Date: Fri, 24 Jul 2026 21:49:05 +0100
Subject: [PATCH] render: declare copy-source usage on the readback source
 textures

---
 src/skate3_native_scene_gpu.cpp  | 6 ++++++
 src/skate3_native_scene_post.cpp | 6 +++++-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/skate3_native_scene_gpu.cpp b/src/skate3_native_scene_gpu.cpp
index 60cbd44..f2009df 100644
--- a/src/skate3_native_scene_gpu.cpp
+++ b/src/skate3_native_scene_gpu.cpp
@@ -3634,6 +3634,12 @@ bool EnsureShadowResources(const NativeGuestOutputRenderContext& context) {
     nrhi::TextureView** views[3] = {&g_r.shadow_srv_raw, &g_r.shadow_srv_mid,
                                     &g_r.shadow_srv_final};
     for (int t = 0; t < 3; ++t) {
+      // The raw and final tiles are the shadow-dump readback sources, so
+      // those two also need copy-source usage; the intermediate is never
+      // copied and stays render-target only.
+      desc.usage = nrhi::kTextureUsageRenderTarget |
+                   (t != 1 ? nrhi::kTextureUsageCopySource
+                           : nrhi::kTextureUsageNone);
       *targets[t] = device->CreateTexture(desc);
       if (*targets[t] == nullptr) {
         REXLOG_ERROR("native-scene: shadow atlas creation failed");
diff --git a/src/skate3_native_scene_post.cpp b/src/skate3_native_scene_post.cpp
index 1e7a9d0..cc81b89 100644
--- a/src/skate3_native_scene_post.cpp
+++ b/src/skate3_native_scene_post.cpp
@@ -488,7 +488,11 @@ bool ApplySsaoPass(const NativeGuestOutputRenderContext& context,
       td.height = RendererState::kOcclGridH;
       td.mip_levels = 1;
       td.format = nrhi::Format::kR32_FLOAT;
-      td.usage = nrhi::kTextureUsageRenderTarget;
+      // The grid is read back to the CPU every frame, so it must declare
+      // copy-source usage: the Vulkan backend only requests TRANSFER_SRC for
+      // textures that ask for it, and both the transition to the copy-source
+      // state and the copy itself are invalid without it.
+      td.usage = nrhi::kTextureUsageRenderTarget | nrhi::kTextureUsageCopySource;
       td.initial_state = nrhi::ResourceState::kRenderTarget;
       g_r.occl_tex = device->CreateTexture(td);
       nrhi::BufferDesc bd;