Add a program iterator to SkDeferredDisplayList

Bug: skia:9455
Change-Id: I201218174b5d6efb72f7c06766a49f6711325bd5
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/272530
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>

Author: rphilli

RELEASE_NOTES.txt

@@ -7,6 +7,10 @@ This file includes a list of high level updates for each milestone release.
 Milestone 82
 
 <Insert new notes here- top is most recent.>
+  * Made SkDeferredDisplayList.h officially part of the public API (i.e., moved it to
+    include/core). Also added a ProgramIterator to SkDeferredDisplayList which allows
+    clients to pre-compile some of the shaders the DDL requires.
+
   * Added two new helper methods to SkSurfaceCharacterization: createBackendFormat and
     createFBO0. These make it easier for clients to create new surface characterizations that
     differ only a little from an existing surface characterization.

include/core/SkDeferredDisplayList.h

@@ -35,6 +35,26 @@ class SkDeferredDisplayList {
         return fCharacterization;
     }
 
+#if SK_SUPPORT_GPU
+    /**
+     * Iterate through the programs required by the DDL.
+     */
+    class SK_API ProgramIterator {
+    public:
+        ProgramIterator(GrContext*, SkDeferredDisplayList*);
+        ~ProgramIterator();
+
+        void compile();
+        bool done() const;
+        void next();
+
+    private:
+        GrContext*                                       fContext;
+        const SkTArray<GrRecordingContext::ProgramData>& fProgramData;
+        int                                              fIndex;
+    };
+#endif
+
     // Provides access to functions that aren't part of the public API.
     SkDeferredDisplayListPriv priv();
     const SkDeferredDisplayListPriv priv() const;

src/core/SkDeferredDisplayList.cpp

@@ -14,6 +14,7 @@
 class SkSurfaceCharacterization;
 
 #if SK_SUPPORT_GPU
+#include "src/gpu/GrContextPriv.h"
 #include "src/gpu/GrRenderTask.h"
 #include "src/gpu/ccpr/GrCCPerOpsTaskPaths.h"
 #endif
@@ -28,3 +29,33 @@ SkDeferredDisplayList::SkDeferredDisplayList(const SkSurfaceCharacterization& ch
 }
 
 SkDeferredDisplayList::~SkDeferredDisplayList() {}
+
+//-------------------------------------------------------------------------------------------------
+#if SK_SUPPORT_GPU
+
+SkDeferredDisplayList::ProgramIterator::ProgramIterator(GrContext* context,
+                                                        SkDeferredDisplayList* ddl)
+    : fContext(context)
+    , fProgramData(ddl->programData())
+    , fIndex(0) {
+}
+
+SkDeferredDisplayList::ProgramIterator::~ProgramIterator() {}
+
+void SkDeferredDisplayList::ProgramIterator::compile() {
+    if (!fContext || fIndex < 0 || fIndex >= (int) fProgramData.size()) {
+        return;
+    }
+
+    fContext->priv().compile(fProgramData[fIndex].desc(), fProgramData[fIndex].info());
+}
+
+bool SkDeferredDisplayList::ProgramIterator::done() const {
+    return fIndex >= (int) fProgramData.size();
+}
+
+void SkDeferredDisplayList::ProgramIterator::next() {
+    ++fIndex;
+}
+
+#endif

tools/DDLTileHelper.cpp

@@ -164,11 +164,11 @@ void DDLTileHelper::createDDLsInParallel() {
 //    replay the DDL into a surface to make the tile image
 //    compose the tile image into the main canvas
 static void do_gpu_stuff(GrContext* context, DDLTileHelper::TileData* tile) {
-    auto& programData = tile->ddl()->priv().programData();
 
     // TODO: schedule program compilation as their own tasks
-    for (auto& programDatum : programData) {
-        context->priv().compile(programDatum.desc(), programDatum.info());
+    SkDeferredDisplayList::ProgramIterator iter(context, tile->ddl());
+    for (; !iter.done(); iter.next()) {
+        iter.compile();
     }
 
     tile->draw(context);