Help: the System Compatibility Report says why there is no GPU and names the window's adapter (#596)

With no GPU compositor the report only said "GPU: none", though the host had recorded the
reason (`Session::accel_note`: the compositor's setup error, a retired GPU preview, a
headless start) and the window's wgpu adapter was known. Users with a capable GPU (#596, an
RTX 4070) couldn't tell why it wasn't used.

The report now carries `gpuNote` (the reason, when there is no compositor) and
`windowGraphics` (the adapter, backend, device type and driver the window draws with, which
the desktop app records when it sets up the GPU), and the text shows
"GPU: none (CPU compositing): <reason>" and "Window graphics: …"; the issue line names the
reason too.

Test: the compatibility report test sets a reason and an adapter and checks the JSON and text.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01QiAJeFttZp83Fh7YuzAR5f

crates/engine/src/commands/app_more.rs

@@ -328,7 +328,10 @@ pub fn system_report(s: &Session) -> Value {
     let budgets = s.prefs.cache_budgets(mem.or(s.sys_memory));
     let mut issues = vec![];
     if gpu.is_none() {
-        issues.push("No GPU compositor: rendering uses the CPU (all features still work).".to_string());
+        issues.push(match &s.accel_note {
+            Some(why) => format!("No GPU compositor ({why}): rendering uses the CPU (all features still work)."),
+            None => "No GPU compositor: rendering uses the CPU (all features still work).".to_string(),
+        });
     }
     if mem.is_some_and(|m| m.total < 8 << 30) {
         issues.push("Less than 8 GB of memory: use lower preview resolutions for long or large comps.".to_string());
@@ -344,6 +347,8 @@ pub fn system_report(s: &Session) -> Value {
         "cores": crate::sysinfo::cpu_cores(),
         "memory": mem.map(|m| json!({"total": gb(m.total), "available": gb(m.available)})),
         "gpu": gpu,
+        "gpuNote": if gpu.is_none() { s.accel_note.clone() } else { None },
+        "windowGraphics": s.window_adapter,
         "caches": {"layer": gb(budgets.layer as u64), "footage": gb(budgets.media as u64), "preview": gb(budgets.preview as u64)},
         "import": IMPORT_FORMATS,
         "export": export,
@@ -369,7 +374,14 @@ pub fn report_text(r: &Value) -> String {
         Some(m) => t.push_str(&format!("Memory: {} ({} available)\n", m["total"].as_str().unwrap_or("?"), m["available"].as_str().unwrap_or("?"))),
         None => t.push_str("Memory: unknown\n"),
     }
-    t.push_str(&format!("GPU: {}\n", r.get("gpu").and_then(Value::as_str).unwrap_or("none (CPU compositing)")));
+    match (r.get("gpu").and_then(Value::as_str), r.get("gpuNote").and_then(Value::as_str)) {
+        (Some(gpu), _) => t.push_str(&format!("GPU: {gpu}\n")),
+        (None, Some(why)) => t.push_str(&format!("GPU: none (CPU compositing): {why}\n")),
+        (None, None) => t.push_str("GPU: none (CPU compositing)\n"),
+    }
+    if let Some(w) = r.get("windowGraphics").and_then(Value::as_str) {
+        t.push_str(&format!("Window graphics: {w}\n"));
+    }
     let c = &r["caches"];
     t.push_str(&format!(
         "Cache budgets: layer {}, footage {}, preview {}\n",

crates/engine/src/lib.rs

@@ -368,6 +368,9 @@ pub struct Session {
     /// Why there is no [`Session::accel`] (`render.backend`'s `why`): the host's reason, e.g. a
     /// headless start without `--gpu` or the compositor's setup error.
     pub accel_note: Option<String>,
+    /// The graphics adapter and backend the window draws with (`NVIDIA GeForce RTX 4070
+    /// (Vulkan)`), as the host reports it: the System Compatibility Report shows it.
+    pub window_adapter: Option<String>,
     /// Expression syntax checker (set by the host that links the expression engine).
     pub expr_check: Option<fn(&str) -> std::result::Result<(), String>>,
     pub importer: Option<Arc<dyn Importer>>,
@@ -511,6 +514,7 @@ impl Default for Session {
             expr: None,
             accel: None,
             accel_note: None,
+            window_adapter: None,
             expr_check: None,
             importer: None,
             exporter: None,

crates/engine/src/tests_m145.rs

@@ -455,6 +455,15 @@ fn compatibility_report_and_logging() {
     }
     let text = crate::commands::report_text_for_tests(&r);
     assert!(text.contains("Operating system") && text.contains("Import:"));
+    // #596: without a GPU compositor the report says why, and names the window's adapter.
+    s.accel_note = Some("GPU compositor unavailable: no storage textures".into());
+    s.window_adapter = Some("NVIDIA GeForce RTX 4070 (Gl, DiscreteGpu)".into());
+    let r = s.execute("help.systemReport", json!({"quiet": true})).unwrap();
+    assert_eq!(r["gpuNote"], "GPU compositor unavailable: no storage textures");
+    let text = crate::commands::report_text_for_tests(&r);
+    assert!(text.contains("GPU: none (CPU compositing): GPU compositor unavailable: no storage textures"), "{text}");
+    assert!(text.contains("Window graphics: NVIDIA GeForce RTX 4070 (Gl, DiscreteGpu)"), "{text}");
+    assert!(r["issues"][0].as_str().is_some_and(|i| i.contains("no storage textures")), "{r}");
     s.drain_events();
     s.execute("help.systemReport", json!({})).unwrap();
     assert!(s.drain_events().iter().any(|e| matches!(e, crate::Event::Frontend { command, .. } if command == "app.showReport")));

crates/ui-egui/src/lib.rs

@@ -612,6 +612,15 @@ impl EffectcraftApp {
             return;
         }
         let Some(rs) = frame.wgpu_render_state() else { return };
+        // Help ▸ System Compatibility Report names the adapter and backend the window got.
+        let info = rs.adapter.get_info();
+        self.session.window_adapter = Some(format!(
+            "{} ({:?}, {:?}{})",
+            info.name,
+            info.backend,
+            info.device_type,
+            if info.driver.is_empty() { String::new() } else { format!(", {} {}", info.driver, info.driver_info) }
+        ));
         // Backend validation can panic on shader compilation even when device creation
         // succeeded. Keep the document and the egui renderer, and use CPU compositing.
         let gpu = std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| effectcraft_gpu::Gpu::new(&rs.adapter, rs.device.clone(), rs.queue.clone())));