Fix issues with calling resolve_queries multiple times per frame

CHANGELOG.md

@@ -1,6 +1,7 @@
 # Change Log
 
 ## Unreleased
+* fix issues with multiple calls to `GpuProfiler::resolve_queries` per frame, in [#79](https://github.com/Wumpf/wgpu-profiler/pull/79)
 
 ## 0.18.0
 * update to wgpu 22.1.0, by @waywardmonkeys in [#75](https://github.com/Wumpf/wgpu-profiler/pull/75)

src/profiler.rs

@@ -355,23 +355,28 @@ impl GpuProfiler {
 
             assert!(num_resolved_queries < num_used_queries);
 
+            // Resolve into offset 0 of the resolve buffer - this way we don't have to worry about
+            // the offset restrictions on resolve buffers (`wgpu::QUERY_RESOLVE_BUFFER_ALIGNMENT`)
+            // and we copy it anyways.
             encoder.resolve_query_set(
                 &query_pool.query_set,
                 num_resolved_queries..num_used_queries,
                 &query_pool.resolve_buffer,
-                (num_resolved_queries * wgpu::QUERY_SIZE) as u64,
+                0,
             );
-            query_pool
-                .num_resolved_queries
-                .store(num_used_queries, Ordering::Release);
-
+            // Copy the resolved queries into the read buffer, making sure
+            // that we don't override any of the results that are already there.
             encoder.copy_buffer_to_buffer(
                 &query_pool.resolve_buffer,
                 0,
                 &query_pool.read_buffer,
-                0,
+                (num_resolved_queries * wgpu::QUERY_SIZE) as u64,
                 (num_used_queries * wgpu::QUERY_SIZE) as u64,
             );
+
+            query_pool
+                .num_resolved_queries
+                .store(num_used_queries, Ordering::Release);
         }
     }
 

tests/src/mod.rs

@@ -1,6 +1,7 @@
 mod dropped_frame_handling;
 mod errors;
 mod interleaved_command_buffer;
+mod multiple_resolves_per_frame;
 mod nested_scopes;
 
 pub fn create_device(

tests/src/multiple_resolves_per_frame.rs

@@ -0,0 +1,38 @@
+// Regression test for bug described in https://github.com/Wumpf/wgpu-profiler/issues/79
+#[test]
+fn multiple_resolves_per_frame() {
+    let (_, device, queue) = super::create_device(
+        wgpu::Features::TIMESTAMP_QUERY.union(wgpu::Features::TIMESTAMP_QUERY_INSIDE_ENCODERS),
+    )
+    .unwrap();
+
+    let mut profiler =
+        wgpu_profiler::GpuProfiler::new(wgpu_profiler::GpuProfilerSettings::default()).unwrap();
+
+    {
+        let mut encoder = device.create_command_encoder(&wgpu::CommandEncoderDescriptor::default());
+
+        // Resolve call per scope.
+        {
+            let _ = profiler.scope("testscope0", &mut encoder, &device);
+        }
+        profiler.resolve_queries(&mut encoder);
+        {
+            let _ = profiler.scope("testscope1", &mut encoder, &device);
+        }
+        profiler.resolve_queries(&mut encoder);
+
+        // And an extra resolve for good measure (this should be a no-op).
+        profiler.resolve_queries(&mut encoder);
+
+        profiler.end_frame().unwrap();
+    }
+
+    // Poll to explicitly trigger mapping callbacks.
+    device.poll(wgpu::Maintain::Wait);
+
+    // Frame should now be available.
+    assert!(profiler
+        .process_finished_frame(queue.get_timestamp_period())
+        .is_some());
+}