commit 028df5f51e45f50ebfef480fd93fc9325a7bf0b8
author Shahbaz Youssefi <syoussefi@chromium.org> Wed Feb 13 12:57:10 2019 -0500
committer Commit Bot <commit-bot@chromium.org> Sat Feb 16 04:54:55 2019 +0000
tree 124b3ed00a9b2c24f0e844287a2456829b3036b4
parent 8a64926e62565a5d9decc7a2a16024b6b2b4e343

Vulkan: Implement transfer path for texture copy

This is primarily in preparation for compressed texture copy, but has
the following side effect:

- When transfer is possible, it's faster than draw
- When texture format does not support draw (but transfer is possible),
  it will avoid copying through CPU.

Bug: angleproject:2670
Change-Id: I49e1b51e6ccec875db3f971106687c7d48c4916f
Reviewed-on: https://chromium-review.googlesource.com/c/1470595
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>

src/libANGLE/renderer/vulkan/RenderTargetVk.cpp

diff --git a/src/libANGLE/renderer/vulkan/RenderTargetVk.cpp b/src/libANGLE/renderer/vulkan/RenderTargetVk.cpp
index 1ac608a..8035c8e 100644
--- a/src/libANGLE/renderer/vulkan/RenderTargetVk.cpp
+++ b/src/libANGLE/renderer/vulkan/RenderTargetVk.cpp
@@ -140,6 +140,20 @@
     ASSERT(mImage && mImage->valid());
 
     // TODO(jmadill): Better simultaneous resource access. http://anglebug.com/2679
+    //
+    // A better alternative would be:
+    //
+    // if (mImage->isLayoutChangeNecessary(layout)
+    // {
+    //     vk::CommandBuffer *srcLayoutChange;
+    //     ANGLE_TRY(mImage->recordCommands(contextVk, &srcLayoutChange));
+    //     mImage->changeLayout(mImage->getAspectFlags(), layout, srcLayoutChange);
+    // }
+    // mImage->addReadDependency(readingResource);
+    //
+    // I.e. the transition should happen on a node generated from mImage itself.
+    // However, this needs context to be available here, or all call sites changed
+    // to perform the layout transition and set the dependency.
     mImage->addWriteDependency(readingResource);
 
     mImage->changeLayout(mImage->getAspectFlags(), layout, commandBuffer);