render: surface the sticky-failure fallback (EMULATED readout, F5 retry, forced-failure debug hook)

src/skate3_native_debug_dialog.cpp

@@ -1221,12 +1221,14 @@ void NativeDebugDialog::OnDraw(ImGuiIO& io) {
 
 void RenderModeIndicator::OnDraw(ImGuiIO& io) {
   // Force-show while the native scene renderer is switched off (F5, the
-  // settings Renderer row, or the boot-time hook-layer master): running
+  // settings Renderer row, or the boot-time hook-layer master) or has hit an
-  // emulated is a degraded state the player should be able to see even with
+  // unrecoverable failure and permanently yields to the emulated output:
-  // the indicator cvar off. Natural per-frame yields while the scene
+  // running emulated is a degraded state the player should be able to see
-  // renderer is enabled (menus/loading) do not trigger this.
+  // even with the indicator cvar off. Natural per-frame yields while the
+  // scene renderer is enabled (menus/loading) do not trigger this.
   const bool scene_off = !REXCVAR_GET(skate3_native_render) ||
-                         !REXCVAR_GET(skate3_native_render_scene);
+                         !REXCVAR_GET(skate3_native_render_scene) ||
+                         skate3::native_scene::SceneFailed();
   if (!REXCVAR_GET(skate3_native_render_mode_indicator) && !scene_off) {
     return;
   }

src/skate3_native_scene.cpp

@@ -710,6 +710,17 @@ REXCVAR_DEFINE_INT32(skate3_native_render_scene_shadow_static_size, 4096,
                      "~9 cm. Applies live: the map recreates on change.")
     .range(1024, 8192)
     .lifecycle(rex::cvar::Lifecycle::kHotReload);
+REXCVAR_DEFINE_INT32(skate3_native_render_scene_debug_fail_static_sun, 0,
+                     "Skate 3",
+                     "DEBUG: make static sun-shadow map creation fail as if "
+                     "the allocation had been rejected, driving the "
+                     "renderer's unrecoverable-failure path (sticky fallback "
+                     "to emulated output). 0 = off, 1 = fail every creation, "
+                     "2 = fail only hot recreates (size changes after a "
+                     "successful first build). Exercises the failure "
+                     "indicator and the shutdown path from the failed state.")
+    .range(0, 2)
+    .lifecycle(rex::cvar::Lifecycle::kHotReload);
 REXCVAR_DEFINE_BOOL(skate3_native_render_scene_shadow_pcss, true, "Skate 3",
                     "Contact-hardening soft shadows (PCSS): a blocker search "
                     "estimates the caster distance per pixel and the filter "
@@ -2551,6 +2562,10 @@ bool ToggleSceneEnabled() {
   }
   const bool enabled = !SceneEnabled();
   if (enabled) {
+    // Re-enabling doubles as the retry gesture after a hard pipeline
+    // failure (which yields to the emulated output while the cvars stay
+    // on): clear the latch so EnsurePipeline runs again.
+    ResetSceneFailure();
     // Capture idles while the emulated renderer is active, so anything still
     // published is from before the switch away (stale camera). Drop it:
     // RenderScene yields to the emulated frame until the capture hooks

src/skate3_native_scene.h

@@ -650,6 +650,17 @@ void Install();
 // layer was not enabled at boot.
 bool ToggleSceneEnabled();
 
+// True once the scene renderer has hit an unrecoverable pipeline/resource
+// failure and yields to the emulated output until re-enabled. Surfaced so
+// the render-mode indicator can show the degraded state even though the
+// renderer cvars are still enabled.
+bool SceneFailed();
+
+// Clears the sticky failure so the next frame retries the full pipeline
+// build (ToggleSceneEnabled calls this on re-enable: a transient allocation
+// failure can succeed on retry; a persistent one simply re-latches).
+void ResetSceneFailure();
+
 // Debug-dialog cache flushes (F12 native-render debug menu): retire every
 // cached GPU texture / mesh decode so hot-toggled decode settings (mip
 // chains, revalidation, ...) rebuild immediately.

src/skate3_native_scene_gpu.cpp

@@ -106,6 +106,7 @@ REXCVAR_DECLARE(double, skate3_native_render_scene_shadow_pcss_sun_deg);
 REXCVAR_DECLARE(double, skate3_native_render_scene_shadow_static_bias);
 REXCVAR_DECLARE(double, skate3_native_render_scene_shadow_static_radius);
 REXCVAR_DECLARE(int32_t, skate3_native_render_scene_shadow_static_size);
+REXCVAR_DECLARE(int32_t, skate3_native_render_scene_debug_fail_static_sun);
 REXCVAR_DECLARE(double, skate3_native_render_scene_shadow_static_strength);
 REXCVAR_DECLARE(bool, skate3_native_render_scene_shadows);
 REXCVAR_DECLARE(bool, skate3_native_render_scene_shafts);
@@ -3312,6 +3313,13 @@ bool EnsureShadowResources(const NativeGuestOutputRenderContext& context) {
     // tiles side by side: inner (r/6, centimeter contact detail with
     // useful reach), mid (r/2) and far (full radius, large-caster
     // coverage); size is per tile.
+    // Forced-failure debug hook (see the cvar's help text): mode 1 fails
+    // every creation, mode 2 only hot recreates; retries are skipped so the
+    // sticky-failed path below engages like a hard driver rejection.
+    const int32_t debug_fail =
+        REXCVAR_GET(skate3_native_render_scene_debug_fail_static_sun);
+    const bool force_fail =
+        debug_fail == 1 || (debug_fail == 2 && g_r.static_sun_requested != 0);
     g_r.static_sun_requested = want_static_size;
     g_r.static_sun_size = want_static_size;
     nrhi::TextureDesc desc;
@@ -3322,11 +3330,11 @@ bool EnsureShadowResources(const NativeGuestOutputRenderContext& context) {
     desc.initial_state = nrhi::ResourceState::kRenderTarget;
     desc.clear_color[0] = 1.0f;  // depth: far = lit
     desc.clear_color[1] = 1.0f;
-    g_r.static_sun = device->CreateTexture(desc);
+    g_r.static_sun = force_fail ? nullptr : device->CreateTexture(desc);
     // Allocation-failure fallback (VRAM pressure, driver limits): a
     // coarser static sun map beats marking the whole renderer failed and
     // dropping the session to emulated output.
-    while (g_r.static_sun == nullptr && g_r.static_sun_size > 1024) {
+    while (!force_fail && g_r.static_sun == nullptr && g_r.static_sun_size > 1024) {
       g_r.static_sun_size /= 2;
       desc.width = g_r.static_sun_size * 3;
       desc.height = g_r.static_sun_size;
@@ -10633,6 +10641,17 @@ bool RenderScene(const NativeGuestOutputRenderContext& context, void* /*user_dat
 
 }  // namespace
 
+bool SceneFailed() { return g_r.failed; }
+
+void ResetSceneFailure() {
+  if (g_r.failed) {
+    g_r.failed = false;
+    REXLOG_INFO(
+        "native-scene: sticky pipeline failure cleared; the next frame "
+        "retries the full pipeline build");
+  }
+}
+
 void Install() {
   // Registered even when the scene cvar starts off: RenderScene yields to the
   // emulated output while disabled, and the runtime toggle (F5) can flip the
@@ -10652,6 +10671,8 @@ void Install() {
 
 namespace skate3::native_scene {
 void Install() {}
+bool SceneFailed() { return false; }
+void ResetSceneFailure() {}
 }  // namespace skate3::native_scene
 
 #endif  // REX_HAS_D3D12 || REX_HAS_VULKAN