test: log retained underlay debug counters

src/mbgl/renderer/renderer_impl.cpp

@@ -20,6 +20,10 @@
 #include <mbgl/util/logging.hpp>
 #include <mbgl/util/instrumentation.hpp>
 
+#ifndef NDEBUG
+#include <sstream>
+#endif
+
 #include <mbgl/gfx/drawable_tweaker.hpp>
 #include <mbgl/renderer/layer_tweaker.hpp>
 #include <mbgl/renderer/render_target.hpp>
@@ -51,6 +55,30 @@ RendererObserver& nullObserver() {
     return observer;
 }
 
+#ifndef NDEBUG
+constexpr uint64_t RetainedCounterLogIntervalFrames = 120;
+
+void logRetainedRendererCounters() {
+    const auto snapshot = particle::rendererDebugCounterSnapshot();
+    if (snapshot.fullRendererFrame == 0 ||
+        snapshot.fullRendererFrame % RetainedCounterLogIntervalFrames != 0) {
+        return;
+    }
+
+    std::ostringstream message;
+    message << "ParticleRetained:"
+            << " frame=" << snapshot.fullRendererFrame
+            << " build=" << snapshot.retainedUnderlayBuild
+            << " reuse=" << snapshot.retainedUnderlayReuse
+            << " fallback=" << snapshot.retainedUnderlayFallback
+            << " invalidation=" << snapshot.retainedUnderlayInvalidation
+            << " staticDraw=" << snapshot.retainedUnderlayStaticGroupDraw
+            << " dynamicDraw=" << snapshot.retainedDynamicGroupDraw
+            << " particleAdvance=" << snapshot.particleSimulationAdvance;
+    Log::Info(Event::Render, message.str());
+}
+#endif
+
 } // namespace
 
 Renderer::Impl::Impl(gfx::RendererBackend& backend_,
@@ -590,6 +618,10 @@ void Renderer::Impl::render(const RenderTree& renderTree, const std::shared_ptr<
         observer->onDidFinishRenderingMap();
     }
 
+#ifndef NDEBUG
+    logRetainedRendererCounters();
+#endif
+
     frameCount += 1;
     MLN_END_FRAME();
 }