SF: Move beginFrame to CompositionEngine
Test: atest libsurfaceflinger_unittest libcompositionengine_test
Bug: 121291683
Change-Id: I80d963f1befd88c52e17aa9ed5989d28f5dd0c13
diff --git a/services/surfaceflinger/CompositionEngine/src/Output.cpp b/services/surfaceflinger/CompositionEngine/src/Output.cpp
index 6d060e4..b411e0a 100644
--- a/services/surfaceflinger/CompositionEngine/src/Output.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/Output.cpp
@@ -251,6 +251,34 @@
return std::move(mReleasedLayers);
}
+void Output::beginFrame() {
+ const bool dirty = !getDirtyRegion(false).isEmpty();
+ const bool empty = mOutputLayersOrderedByZ.empty();
+ const bool wasEmpty = !mState.lastCompositionHadVisibleLayers;
+
+ // If nothing has changed (!dirty), don't recompose.
+ // If something changed, but we don't currently have any visible layers,
+ // and didn't when we last did a composition, then skip it this time.
+ // The second rule does two things:
+ // - When all layers are removed from a display, we'll emit one black
+ // frame, then nothing more until we get new layers.
+ // - When a display is created with a private layer stack, we won't
+ // emit any black frames until a layer is added to the layer stack.
+ const bool mustRecompose = dirty && !(empty && wasEmpty);
+
+ const char flagPrefix[] = {'-', '+'};
+ static_cast<void>(flagPrefix);
+ ALOGV_IF("%s: %s composition for %s (%cdirty %cempty %cwasEmpty)", __FUNCTION__,
+ mustRecompose ? "doing" : "skipping", getName().c_str(), flagPrefix[dirty],
+ flagPrefix[empty], flagPrefix[wasEmpty]);
+
+ mRenderSurface->beginFrame(mustRecompose);
+
+ if (mustRecompose) {
+ mState.lastCompositionHadVisibleLayers = !empty;
+ }
+}
+
void Output::prepareFrame() {
ATRACE_CALL();
ALOGV(__FUNCTION__);