Overdraw avoidance in new pipeline

bug:27873093

Adds the simple overdraw avoidance optimization to the new
pipeline. This means when LayerBuilder defers draws that are opaque over
the full area of the repaint region, it will discard all drawing content
beneth.

Also moves a lot of complexity out of BakedOpState's header.

Change-Id: Iffca6d8e1b170ef31a5d6c83d25592670e02323d

1 files changed, 25 insertions, 9 deletions

diff --git a/libs/hwui/LayerBuilder.cpp b/libs/hwui/LayerBuilder.cpp
index e6a95ff177a4..eea11bff7d8a 100644
--- a/libs/hwui/LayerBuilder.cpp
+++ b/libs/hwui/LayerBuilder.cpp
@@ -236,6 +236,21 @@ void LayerBuilder::deferLayerClear(const Rect& rect) {
     mClearRects.push_back(rect);
 }
 
+void LayerBuilder::onDeferOp(LinearAllocator& allocator, const BakedOpState* bakedState) {
+    if (bakedState->op->opId != RecordedOpId::CopyToLayerOp) {
+        // First non-CopyToLayer, so stop stashing up layer clears for unclipped save layers,
+        // and issue them together in one draw.
+        flushLayerClears(allocator);
+
+        if (CC_UNLIKELY(activeUnclippedSaveLayers.empty()
+                && bakedState->computedState.opaqueOverClippedBounds
+                && bakedState->computedState.clippedBounds.contains(repaintRect))) {
+            // discard all deferred drawing ops, since new one will occlude them
+            clear();
+        }
+    }
+}
+
 void LayerBuilder::flushLayerClears(LinearAllocator& allocator) {
     if (CC_UNLIKELY(!mClearRects.empty())) {
         const int vertCount = mClearRects.size() * 4;
@@ -270,11 +285,7 @@ void LayerBuilder::flushLayerClears(LinearAllocator& allocator) {
 
 void LayerBuilder::deferUnmergeableOp(LinearAllocator& allocator,
         BakedOpState* op, batchid_t batchId) {
-    if (batchId != OpBatchType::CopyToLayer) {
-        // if first op after one or more unclipped saveLayers, flush the layer clears
-        flushLayerClears(allocator);
-    }
-
+    onDeferOp(allocator, op);
     OpBatch* targetBatch = mBatchLookup[batchId];
 
     size_t insertBatchIndex = mBatches.size();
@@ -295,10 +306,7 @@ void LayerBuilder::deferUnmergeableOp(LinearAllocator& allocator,
 
 void LayerBuilder::deferMergeableOp(LinearAllocator& allocator,
         BakedOpState* op, batchid_t batchId, mergeid_t mergeId) {
-    if (batchId != OpBatchType::CopyToLayer) {
-        // if first op after one or more unclipped saveLayers, flush the layer clears
-        flushLayerClears(allocator);
-    }
+    onDeferOp(allocator, op);
     MergingOpBatch* targetBatch = nullptr;
 
     // Try to merge with any existing batch with same mergeId
@@ -348,6 +356,14 @@ void LayerBuilder::replayBakedOpsImpl(void* arg,
     }
 }
 
+void LayerBuilder::clear() {
+    mBatches.clear();
+    for (int i = 0; i < OpBatchType::Count; i++) {
+        mBatchLookup[i] = nullptr;
+        mMergingBatchLookup[i].clear();
+    }
+}
+
 void LayerBuilder::dump() const {
     ALOGD("LayerBuilder %p, %ux%u buffer %p, blo %p, rn %p (%s)",
             this, width, height, offscreenBuffer, beginLayerOp,