make SkiaSalGraphicsImpl use GPU-backed SkSurface also for offscreen

Skia's sk_app::WindowContext can create GPU-backed SkSurface only
for windows, but we also use virtual devices that are not windows.
Fortunately, SkSurface can be created GPU-backed from GrContext*
and sk_gpu_test::GrContextFactory seems to provide it easily.
It is not completely clear to me what the rules are on mixing
SkSurface's with different GrContext* (see the comment
in SkiaSalGraphicsImpl::copyBits()), but it seems to work fine.

Change-Id: I8110b67c41ab092e0c4b6a0973d6bed8a408c4c1

4 files changed, 86 insertions, 6 deletions

diff --git a/vcl/skia/gdiimpl.cxx b/vcl/skia/gdiimpl.cxx
index f505e7778d64..612e097b6e12 100644
--- a/vcl/skia/gdiimpl.cxx
+++ b/vcl/skia/gdiimpl.cxx
@@ -407,6 +407,8 @@ void SkiaSalGraphicsImpl::drawPixel(long nX, long nY, Color nColor)
     paint.setColor(toSkColor(nColor));
     // Apparently drawPixel() is actually expected to set the pixel and not draw it.
     paint.setBlendMode(SkBlendMode::kSrc); // set as is, including alpha
+    if (isGPU()) // TODO this may need caching?
+        ++nX; // https://bugs.chromium.org/p/skia/issues/detail?id=9611
     canvas->drawPoint(nX, nY, paint);
     postDraw();
 }
@@ -677,7 +679,6 @@ void SkiaSalGraphicsImpl::copyArea(long nDestX, long nDestY, long nSrcX, long nS
                                      << Size(nSrcWidth, nSrcHeight));
     sk_sp<SkImage> image
         = mSurface->makeImageSnapshot(SkIRect::MakeXYWH(nSrcX, nSrcY, nSrcWidth, nSrcHeight));
-    // TODO makeNonTextureImage() ?
     mSurface->getCanvas()->drawImage(image, nDestX, nDestY);
     postDraw();
 }
@@ -690,14 +691,18 @@ void SkiaSalGraphicsImpl::copyBits(const SalTwoRect& rPosAry, SalGraphics* pSrcG
     {
         assert(dynamic_cast<SkiaSalGraphicsImpl*>(pSrcGraphics->GetImpl()));
         src = static_cast<SkiaSalGraphicsImpl*>(pSrcGraphics->GetImpl());
+        src->checkSurface();
+        // TODO Without this flush() Skia asserts if both src and destination are
+        // GPU-backed SkSurface that come from different GrContext (e.g. when
+        // src comes from SkiaVulkanGrContext and target is a window). I don't
+        // know if it's a Skia bug or our GrContext usage is incorrect.
+        src->mSurface->flush();
     }
     else
         src = this;
-    src->checkSurface();
     SAL_INFO("vcl.skia", "copybits(" << this << "): (" << src << "):" << rPosAry);
     sk_sp<SkImage> image = src->mSurface->makeImageSnapshot(
         SkIRect::MakeXYWH(rPosAry.mnSrcX, rPosAry.mnSrcY, rPosAry.mnSrcWidth, rPosAry.mnSrcHeight));
-    // TODO makeNonTextureImage() ?
     mSurface->getCanvas()->drawImageRect(image,
                                          SkRect::MakeXYWH(rPosAry.mnDestX, rPosAry.mnDestY,
                                                           rPosAry.mnDestWidth,
@@ -1055,7 +1060,8 @@ bool SkiaSalGraphicsImpl::supportsOperation(OutDevSupportType eType) const
 bool SkiaSalGraphicsImpl::isGPU() const
 {
     return mSurface.get()
-           && mSurface->getBackendRenderTarget(SkSurface::kFlushRead_BackendHandleAccess).isValid();
+           && mSurface->getBackendRenderTarget(SkSurface::kFlushWrite_BackendHandleAccess)
+                  .isValid();
 }
 
 #ifdef DBG_UTIL
diff --git a/vcl/skia/vulkan.cxx b/vcl/skia/vulkan.cxx
new file mode 100644
index 000000000000..c5c9093739fc
--- /dev/null
+++ b/vcl/skia/vulkan.cxx
@@ -0,0 +1,39 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Some of this code is based on Skia source code, covered by the following
+ * license notice (see readlicense_oo for the full license):
+ *
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ */
+
+#include <skia/vulkan.hxx>
+
+#include <GrContextFactory.h>
+
+#include <vcl/lazydelete.hxx>
+
+static GrContext* createGrContext()
+{
+    static vcl::DeleteOnDeinit<sk_gpu_test::GrContextFactory> factory(
+        new sk_gpu_test::GrContextFactory);
+    // The factory owns the context.
+    return factory.get()->get(sk_gpu_test::GrContextFactory::kVulkan_ContextType);
+}
+
+GrContext* SkiaVulkanGrContext::getGrContext()
+{
+    static GrContext* context = createGrContext();
+    return context;
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/vcl/skia/win/gdiimpl.cxx b/vcl/skia/win/gdiimpl.cxx
index d54120d5ffce..f908ace261a3 100644
--- a/vcl/skia/win/gdiimpl.cxx
+++ b/vcl/skia/win/gdiimpl.cxx
@@ -12,6 +12,7 @@
 #include <tools/sk_app/win/WindowContextFactory_win.h>
 #include <tools/sk_app/WindowContext.h>
 #include <win/saldata.hxx>
+#include <skia/vulkan.hxx>
 
 #include <SkColorFilter.h>
 #include <SkPixelRef.h>
@@ -44,14 +45,30 @@ void WinSkiaSalGraphicsImpl::Init()
 
 void WinSkiaSalGraphicsImpl::createSurface()
 {
+    destroySurface();
     if (isOffscreen())
+    {
+        switch (renderMethodToUse())
+        {
+            case RenderVulkan:
+                mSurface = SkSurface::MakeRenderTarget(
+                    SkiaVulkanGrContext::getGrContext(), SkBudgeted::kNo,
+                    SkImageInfo::MakeN32Premul(GetWidth(), GetHeight()));
+                assert(mSurface.get());
+#ifdef DBG_UTIL
+                prefillSurface();
+#endif
+                return;
+            default:
+                break;
+        }
         return SkiaSalGraphicsImpl::createSurface();
+    }
     // When created, Init() gets called with size (0,0), which is invalid size
     // for Skia. Creating the actual surface is delayed, so the size should be always
     // valid here, but better check.
     assert(GetWidth() != 0 && GetHeight() != 0);
     sk_app::DisplayParams displayParams;
-    destroySurface();
     switch (renderMethodToUse())
     {
         case RenderRaster:
diff --git a/vcl/skia/x11/gdiimpl.cxx b/vcl/skia/x11/gdiimpl.cxx
index fff94936a33d..af602d35bede 100644
--- a/vcl/skia/x11/gdiimpl.cxx
+++ b/vcl/skia/x11/gdiimpl.cxx
@@ -21,6 +21,8 @@
 #include <tools/sk_app/unix/WindowContextFactory_unix.h>
 #include <tools/sk_app/WindowContext.h>
 
+#include <skia/vulkan.hxx>
+
 X11SkiaSalGraphicsImpl::X11SkiaSalGraphicsImpl(X11SalGraphics& rParent)
     : SkiaSalGraphicsImpl(rParent, rParent.GetGeometryProvider())
     , mX11Parent(rParent)
@@ -38,8 +40,25 @@ void X11SkiaSalGraphicsImpl::Init()
 
 void X11SkiaSalGraphicsImpl::createSurface()
 {
+    destroySurface();
     if (isOffscreen())
+    {
+        switch (renderMethodToUse())
+        {
+            case RenderVulkan:
+                mSurface = SkSurface::MakeRenderTarget(
+                    SkiaVulkanGrContext::getGrContext(), SkBudgeted::kNo,
+                    SkImageInfo::MakeN32Premul(GetWidth(), GetHeight()));
+                assert(mSurface.get());
+#ifdef DBG_UTIL
+                prefillSurface();
+#endif
+                return;
+            default:
+                break;
+        }
         return SkiaSalGraphicsImpl::createSurface();
+    }
     sk_app::DisplayParams displayParams;
     // TODO The Skia Xlib code actually requires the non-native color type to work properly.
     // Use a macro to hide an unreachable code warning.
@@ -59,7 +78,6 @@ void X11SkiaSalGraphicsImpl::createSurface()
     // Avoid this somehow.
     winInfo.fWidth = GetWidth();
     winInfo.fHeight = GetHeight();
-    destroySurface();
     switch (renderMethodToUse())
     {
         case RenderRaster: