Revert "Revert "Clean up onTransferPixels""

Bug: skia:5126
Change-Id: Ia1eaef56cca266ad4c413e711e63646e913222be
Reviewed-on: https://skia-review.googlesource.com/20445
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>

2 files changed, 62 insertions, 4 deletions

diff --git a/src/gpu/vk/GrVkGpu.cpp b/src/gpu/vk/GrVkGpu.cpp
index b10e9ed59d..d237632d9e 100644
--- a/src/gpu/vk/GrVkGpu.cpp
+++ b/src/gpu/vk/GrVkGpu.cpp
@@ -301,11 +301,13 @@ GrBuffer* GrVkGpu::onCreateBuffer(size_t size, GrBufferType type, GrAccessPatter
             buff = GrVkIndexBuffer::Create(this, size, kDynamic_GrAccessPattern == accessPattern);
             break;
         case kXferCpuToGpu_GrBufferType:
-            SkASSERT(kStream_GrAccessPattern == accessPattern);
+            SkASSERT(kDynamic_GrAccessPattern == accessPattern ||
+                     kStream_GrAccessPattern == accessPattern);
             buff = GrVkTransferBuffer::Create(this, size, GrVkBuffer::kCopyRead_Type);
             break;
         case kXferGpuToCpu_GrBufferType:
-            SkASSERT(kStream_GrAccessPattern == accessPattern);
+            SkASSERT(kDynamic_GrAccessPattern == accessPattern ||
+                     kStream_GrAccessPattern == accessPattern);
             buff = GrVkTransferBuffer::Create(this, size, GrVkBuffer::kCopyWrite_Type);
             break;
         case kTexel_GrBufferType:
@@ -420,6 +422,62 @@ bool GrVkGpu::onWritePixels(GrSurface* surface,
     return success;
 }
 
+bool GrVkGpu::onTransferPixels(GrTexture* texture,
+                               int left, int top, int width, int height,
+                               GrPixelConfig config, GrBuffer* transferBuffer,
+                               size_t bufferOffset, size_t rowBytes) {
+    // Vulkan only supports 4-byte aligned offsets
+    if (SkToBool(bufferOffset & 0x2)) {
+        return false;
+    }
+    GrVkTexture* vkTex = static_cast<GrVkTexture*>(texture);
+    if (!vkTex) {
+        return false;
+    }
+    GrVkTransferBuffer* vkBuffer = static_cast<GrVkTransferBuffer*>(transferBuffer);
+    if (!vkBuffer) {
+        return false;
+    }
+
+    // We assume Vulkan doesn't do sRGB <-> linear conversions when reading and writing pixels.
+    if (GrPixelConfigIsSRGB(texture->config()) != GrPixelConfigIsSRGB(config)) {
+        return false;
+    }
+
+    size_t bpp = GrBytesPerPixel(config);
+    if (rowBytes == 0) {
+        rowBytes = bpp*width;
+    }
+
+    // Set up copy region
+    VkBufferImageCopy region;
+    memset(&region, 0, sizeof(VkBufferImageCopy));
+    region.bufferOffset = bufferOffset;
+    region.bufferRowLength = (uint32_t)(rowBytes/bpp);
+    region.bufferImageHeight = 0;
+    region.imageSubresource = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 0, 1 };
+    region.imageOffset = { left, top, 0 };
+    region.imageExtent = { (uint32_t)width, (uint32_t)height, 1 };
+
+    // Change layout of our target so it can be copied to
+    vkTex->setImageLayout(this,
+                          VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
+                          VK_ACCESS_TRANSFER_WRITE_BIT,
+                          VK_PIPELINE_STAGE_TRANSFER_BIT,
+                          false);
+
+    // Copy the buffer to the image
+    fCurrentCmdBuffer->copyBufferToImage(this,
+                                         vkBuffer,
+                                         vkTex,
+                                         VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
+                                         1,
+                                         &region);
+
+    vkTex->texturePriv().dirtyMipMaps(true);
+    return true;
+}
+
 void GrVkGpu::resolveImage(GrSurface* dst, GrVkRenderTarget* src, const SkIRect& srcRect,
                            const SkIPoint& dstPoint) {
     SkASSERT(dst);
diff --git a/src/gpu/vk/GrVkGpu.h b/src/gpu/vk/GrVkGpu.h
index 236b34a3c1..8a3fb09296 100644
--- a/src/gpu/vk/GrVkGpu.h
+++ b/src/gpu/vk/GrVkGpu.h
@@ -203,10 +203,10 @@ private:
                        int left, int top, int width, int height,
                        GrPixelConfig config, const SkTArray<GrMipLevel>&) override;
 
-    bool onTransferPixels(GrSurface*,
+    bool onTransferPixels(GrTexture*,
                           int left, int top, int width, int height,
                           GrPixelConfig config, GrBuffer* transferBuffer,
-                          size_t offset, size_t rowBytes) override { return false; }
+                          size_t offset, size_t rowBytes) override;
 
     // Ends and submits the current command buffer to the queue and then creates a new command
     // buffer and begins it. If sync is set to kForce_SyncQueue, the function will wait for all