src/gpu/vk/GrVkGpu.cpp

/*
 * Copyright 2015 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "GrVkGpu.h"

#include "GrContextOptions.h"
#include "GrGeometryProcessor.h"
#include "GrGpuResourceCacheAccess.h"
#include "GrPipeline.h"
#include "GrRenderTargetPriv.h"
#include "GrSurfacePriv.h"
#include "GrTexturePriv.h"
#include "GrVertices.h"

#include "GrVkCommandBuffer.h"
#include "GrVkImage.h"
#include "GrVkIndexBuffer.h"
#include "GrVkMemory.h"
#include "GrVkPipeline.h"
#include "GrVkProgram.h"
#include "GrVkProgramBuilder.h"
#include "GrVkProgramDesc.h"
#include "GrVkRenderPass.h"
#include "GrVkResourceProvider.h"
#include "GrVkTexture.h"
#include "GrVkTextureRenderTarget.h"
#include "GrVkTransferBuffer.h"
#include "GrVkVertexBuffer.h"

#include "SkConfig8888.h"

#include "vk/GrVkInterface.h"

#define VK_CALL(X) GR_VK_CALL(this->vkInterface(), X)
#define VK_CALL_RET(RET, X) GR_VK_CALL_RET(this->vkInterface(), RET, X)
#define VK_CALL_ERRCHECK(X) GR_VK_CALL_ERRCHECK(this->vkInterface(), X)

////////////////////////////////////////////////////////////////////////////////
// Stuff used to set up a GrVkGpu secrectly for now.

// For now the VkGpuCreate is using the same signature as GL. This is mostly for ease of
// hiding this code from offical skia. In the end the VkGpuCreate will not take a GrBackendContext
// and mostly likely would take an optional device and queues to use.
GrGpu* vk_gpu_create(GrBackendContext backendContext, const GrContextOptions& options,
                     GrContext* context) {
    // Below is Vulkan setup code that normal would be done by a client, but will do here for now
    // for testing purposes.
    VkPhysicalDevice physDev;
    VkDevice device;
    VkInstance inst;
    VkResult err;

    const VkApplicationInfo app_info = {
        VK_STRUCTURE_TYPE_APPLICATION_INFO, // sType
        nullptr,                            // pNext
        "vktest",                           // pApplicationName
        0,                                  // applicationVersion
        "vktest",                           // pEngineName
        0,                                  // engineVerison
        VK_API_VERSION,                     // apiVersion
    };
    const VkInstanceCreateInfo instance_create = {
        VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO, // sType
        nullptr,                                // pNext
        0,                                      // flags
        &app_info,                              // pApplicationInfo
        0,                                      // enabledLayerNameCount
        nullptr,                                // ppEnabledLayerNames
        0,                                      // enabledExtensionNameCount
        nullptr,                                // ppEnabledExtensionNames
    };
    err = vkCreateInstance(&instance_create, nullptr, &inst);
    if (err < 0) {
        SkDebugf("vkCreateInstanced failed: %d\n", err);
        SkFAIL("failing");
    }

    uint32_t gpuCount;
    err = vkEnumeratePhysicalDevices(inst, &gpuCount, nullptr);
    if (err) {
        SkDebugf("vkEnumeratePhysicalDevices failed: %d\n", err);
        SkFAIL("failing");
    }
    SkASSERT(gpuCount > 0);
    // Just returning the first physical device instead of getting the whole array.
    gpuCount = 1;
    err = vkEnumeratePhysicalDevices(inst, &gpuCount, &physDev);
    if (err) {
        SkDebugf("vkEnumeratePhysicalDevices failed: %d\n", err);
        SkFAIL("failing");
    }

    // query to get the initial queue props size
    uint32_t queueCount;
    vkGetPhysicalDeviceQueueFamilyProperties(physDev, &queueCount, nullptr);
    SkASSERT(queueCount >= 1);

    SkAutoMalloc queuePropsAlloc(queueCount * sizeof(VkQueueFamilyProperties));
    // now get the actual queue props
    VkQueueFamilyProperties* queueProps = (VkQueueFamilyProperties*)queuePropsAlloc.get();

    vkGetPhysicalDeviceQueueFamilyProperties(physDev, &queueCount, queueProps);

    // iterate to find the graphics queue
    uint32_t graphicsQueueIndex = -1;
    for (uint32_t i = 0; i < queueCount; i++) {
        if (queueProps[i].queueFlags & VK_QUEUE_GRAPHICS_BIT) {
            graphicsQueueIndex = i;
            break;
        }
    }
    SkASSERT(graphicsQueueIndex < queueCount);

    float queuePriorities[1] = { 0.0 };
    const VkDeviceQueueCreateInfo queueInfo = {
        VK_STRUCTURE_TYPE_DEVICE_QUEUE_CREATE_INFO, // sType
        nullptr,                                    // pNext
        0,                                          // VkDeviceQueueCreateFlags
        0,                                          // queueFamilyIndex
        1,                                          // queueCount
        queuePriorities,                            // pQueuePriorities
    };
    const VkDeviceCreateInfo deviceInfo = {
        VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO,  // sType
        nullptr,                               // pNext
        0,                                     // VkDeviceCreateFlags
        1,                                     // queueCreateInfoCount
        &queueInfo,                            // pQueueCreateInfos
        0,                                     // layerCount
        nullptr,                               // ppEnabledLayerNames
        0,                                     // extensionCount
        nullptr,                               // ppEnabledExtensionNames
        nullptr                                // ppEnabledFeatures
    };

    err = vkCreateDevice(physDev, &deviceInfo, nullptr, &device);
    if (err) {
        SkDebugf("CreateDevice failed: %d\n", err);
        SkFAIL("failing");
    }

    VkQueue queue;
    vkGetDeviceQueue(device, graphicsQueueIndex, 0, &queue);

    const VkCommandPoolCreateInfo cmdPoolInfo = {
        VK_STRUCTURE_TYPE_COMMAND_POOL_CREATE_INFO, // sType
        nullptr,                                    // pNext
        0,                                          // CmdPoolCreateFlags
        graphicsQueueIndex,                         // queueFamilyIndex
    };

    VkCommandPool cmdPool;
    err = vkCreateCommandPool(device, &cmdPoolInfo, nullptr, &cmdPool);
    if (err) {
        SkDebugf("CreateCommandPool failed: %d\n", err);
        SkFAIL("failing");
    }

    return new GrVkGpu(context, options, physDev, device, queue, cmdPool, inst);
}

////////////////////////////////////////////////////////////////////////////////

GrVkGpu::GrVkGpu(GrContext* context, const GrContextOptions& options,
                 VkPhysicalDevice physDev, VkDevice device, VkQueue queue, VkCommandPool cmdPool,
                 VkInstance inst)
    : INHERITED(context)
    , fDevice(device)
    , fQueue(queue)
    , fCmdPool(cmdPool)
    , fResourceProvider(this)
    , fVkInstance(inst) {
    fInterface.reset(GrVkCreateInterface(fVkInstance));
    fCompiler = shaderc_compiler_initialize();

    fVkCaps.reset(new GrVkCaps(options, fInterface, physDev));
    fCaps.reset(SkRef(fVkCaps.get()));

    fResourceProvider.init();

    fCurrentCmdBuffer = fResourceProvider.createCommandBuffer();
    SkASSERT(fCurrentCmdBuffer);
    fCurrentCmdBuffer->begin(this);
    VK_CALL(GetPhysicalDeviceMemoryProperties(physDev, &fPhysDevMemProps));

}

GrVkGpu::~GrVkGpu() {
    shaderc_compiler_release(fCompiler);
    fCurrentCmdBuffer->end(this);
    fCurrentCmdBuffer->unref(this);

    // wait for all commands to finish
    VK_CALL(QueueWaitIdle(fQueue));

    // must call this just before we destroy the VkDevice
    fResourceProvider.destroyResources();

    VK_CALL(DestroyCommandPool(fDevice, fCmdPool, nullptr));
    VK_CALL(DestroyDevice(fDevice, nullptr));
    VK_CALL(DestroyInstance(fVkInstance, nullptr));
}

///////////////////////////////////////////////////////////////////////////////

void GrVkGpu::submitCommandBuffer(SyncQueue sync) {
    SkASSERT(fCurrentCmdBuffer);
    fCurrentCmdBuffer->end(this);

    fCurrentCmdBuffer->submitToQueue(this, fQueue, sync);
    fResourceProvider.checkCommandBuffers();

    // Release old command buffer and create a new one
    fCurrentCmdBuffer->unref(this);
    fCurrentCmdBuffer = fResourceProvider.createCommandBuffer();
    SkASSERT(fCurrentCmdBuffer);

    fCurrentCmdBuffer->begin(this);
}

///////////////////////////////////////////////////////////////////////////////
GrVertexBuffer* GrVkGpu::onCreateVertexBuffer(size_t size, bool dynamic) {
    return GrVkVertexBuffer::Create(this, size, dynamic);
}

GrIndexBuffer* GrVkGpu::onCreateIndexBuffer(size_t size, bool dynamic) {
    return GrVkIndexBuffer::Create(this, size, dynamic);
}

GrTransferBuffer* GrVkGpu::onCreateTransferBuffer(size_t size, TransferType type) {
    GrVkBuffer::Type bufferType = kCpuToGpu_TransferType ? GrVkBuffer::kCopyRead_Type 
                                                         : GrVkBuffer::kCopyWrite_Type;
    return GrVkTransferBuffer::Create(this, size, bufferType);
}

////////////////////////////////////////////////////////////////////////////////
bool GrVkGpu::onGetWritePixelsInfo(GrSurface* dstSurface, int width, int height,
                                   GrPixelConfig srcConfig, DrawPreference* drawPreference,
                                   WritePixelTempDrawInfo* tempDrawInfo) {
    if (kIndex_8_GrPixelConfig == srcConfig || GrPixelConfigIsCompressed(dstSurface->config())) {
        return false;
    }

    // Currently we don't handle draws, so if the caller wants/needs to do a draw we need to fail
    if (kNoDraw_DrawPreference != *drawPreference) {
        return false;
    }

    if (dstSurface->config() != srcConfig) {
        // TODO: This should fall back to drawing or copying to change config of dstSurface to 
        // match that of srcConfig.
        return false;
    }

    return true;
}

bool GrVkGpu::onWritePixels(GrSurface* surface,
                            int left, int top, int width, int height,
                            GrPixelConfig config,
                            const SkTArray<GrMipLevel>& texels) {
    GrVkTexture* vkTex = static_cast<GrVkTexture*>(surface->asTexture());
    if (!vkTex) {
        return false;
    }

    // TODO: We're ignoring MIP levels here.
    if (texels.empty() || !texels.begin()->fPixels) {
        return false;
    }

    // We assume Vulkan doesn't do sRGB <-> linear conversions when reading and writing pixels.
    if (GrPixelConfigIsSRGB(surface->config()) != GrPixelConfigIsSRGB(config)) {
        return false;
    }

    bool success = false;
    if (GrPixelConfigIsCompressed(vkTex->desc().fConfig)) {
        // We check that config == desc.fConfig in GrGpu::getWritePixelsInfo()
        SkASSERT(config == vkTex->desc().fConfig);
        // TODO: add compressed texture support
        // delete the following two lines and uncomment the two after that when ready
        vkTex->unref();
        return false;
        //success = this->uploadCompressedTexData(vkTex->desc(), buffer, false, left, top, width,
        //                                       height);
    } else {
        bool linearTiling = vkTex->isLinearTiled();
        if (linearTiling && VK_IMAGE_LAYOUT_PREINITIALIZED != vkTex->currentLayout()) {
            // Need to change the layout to general in order to perform a host write
            VkImageLayout layout = vkTex->currentLayout();
            VkPipelineStageFlags srcStageMask = GrVkMemory::LayoutToPipelineStageFlags(layout);
            VkPipelineStageFlags dstStageMask = VK_PIPELINE_STAGE_HOST_BIT;
            VkAccessFlags srcAccessMask = GrVkMemory::LayoutToSrcAccessMask(layout);
            VkAccessFlags dstAccessMask = VK_ACCESS_HOST_WRITE_BIT;
            vkTex->setImageLayout(this,
                                  VK_IMAGE_LAYOUT_GENERAL,
                                  srcAccessMask,
                                  dstAccessMask,
                                  srcStageMask,
                                  dstStageMask,
                                  false);
        }
        success = this->uploadTexData(vkTex, left, top, width, height, config,
                                      texels.begin()->fPixels, texels.begin()->fRowBytes);
    }

    if (success) {
        vkTex->texturePriv().dirtyMipMaps(true);
        return true;
    }

    return false;
}

bool GrVkGpu::uploadTexData(GrVkTexture* tex,
                            int left, int top, int width, int height,
                            GrPixelConfig dataConfig,
                            const void* data,
                            size_t rowBytes) {
    SkASSERT(data);

    // If we're uploading compressed data then we should be using uploadCompressedTexData
    SkASSERT(!GrPixelConfigIsCompressed(dataConfig));

    bool linearTiling = tex->isLinearTiled();

    size_t bpp = GrBytesPerPixel(dataConfig);

    const GrSurfaceDesc& desc = tex->desc();

    if (!GrSurfacePriv::AdjustWritePixelParams(desc.fWidth, desc.fHeight, bpp, &left, &top,
                                               &width, &height, &data, &rowBytes)) {
        return false;
    }
    size_t trimRowBytes = width * bpp;

    if (linearTiling) {
        SkASSERT(VK_IMAGE_LAYOUT_PREINITIALIZED == tex->currentLayout() ||
                 VK_IMAGE_LAYOUT_GENERAL == tex->currentLayout());
        const VkImageSubresource subres = {
            VK_IMAGE_ASPECT_COLOR_BIT,
            0,  // mipLevel
            0,  // arraySlice
        };
        VkSubresourceLayout layout;
        VkResult err;

        const GrVkInterface* interface = this->vkInterface();

        GR_VK_CALL(interface, GetImageSubresourceLayout(fDevice,
                                                        tex->textureImage(),
                                                        &subres,
                                                        &layout));

        int texTop = kBottomLeft_GrSurfaceOrigin == desc.fOrigin ? tex->height() - top - height
                                                                    : top;
        VkDeviceSize offset = texTop*layout.rowPitch + left*bpp;
        VkDeviceSize size = height*layout.rowPitch;
        void* mapPtr;
        err = GR_VK_CALL(interface, MapMemory(fDevice, tex->textureMemory(), offset, size, 0, 
                                                &mapPtr));
        if (err) {
            return false;
        }

        if (kBottomLeft_GrSurfaceOrigin == desc.fOrigin) {
            // copy into buffer by rows
            const char* srcRow = reinterpret_cast<const char*>(data);
            char* dstRow = reinterpret_cast<char*>(mapPtr)+(height - 1)*layout.rowPitch;
            for (int y = 0; y < height; y++) {
                memcpy(dstRow, srcRow, trimRowBytes);
                srcRow += rowBytes;
                dstRow -= layout.rowPitch;
            }
        } else {
            // If there is no padding on the src (rowBytes) or dst (layout.rowPitch) we can memcpy
            if (trimRowBytes == rowBytes && trimRowBytes == layout.rowPitch) {
                memcpy(mapPtr, data, trimRowBytes * height);
            } else {
                SkRectMemcpy(mapPtr, layout.rowPitch, data, rowBytes, trimRowBytes, height);
            }
        }

        GR_VK_CALL(interface, UnmapMemory(fDevice, tex->textureMemory()));
    } else {
        GrVkTransferBuffer* transferBuffer =
            GrVkTransferBuffer::Create(this, trimRowBytes * height, GrVkBuffer::kCopyRead_Type);

        void* mapPtr = transferBuffer->map();

        if (kBottomLeft_GrSurfaceOrigin == desc.fOrigin) {
            // copy into buffer by rows
            const char* srcRow = reinterpret_cast<const char*>(data);
            char* dstRow = reinterpret_cast<char*>(mapPtr)+(height - 1)*trimRowBytes;
            for (int y = 0; y < height; y++) {
                memcpy(dstRow, srcRow, trimRowBytes);
                srcRow += rowBytes;
                dstRow -= trimRowBytes;
            }
        } else {
            // If there is no padding on the src data rows, we can do a single memcpy
            if (trimRowBytes == rowBytes) {
                memcpy(mapPtr, data, trimRowBytes * height);
            } else {
                SkRectMemcpy(mapPtr, trimRowBytes, data, rowBytes, trimRowBytes, height);
            }
        }

        transferBuffer->unmap();

        // make sure the unmap has finished
        transferBuffer->addMemoryBarrier(this,
                                         VK_ACCESS_HOST_WRITE_BIT,
                                         VK_ACCESS_TRANSFER_READ_BIT,
                                         VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT,
                                         VK_PIPELINE_STAGE_TRANSFER_BIT,
                                         false);

        // Set up copy region
        bool flipY = kBottomLeft_GrSurfaceOrigin == tex->origin();
        VkOffset3D offset = {
            left,
            flipY ? tex->height() - top - height : top,
            0
        };

        VkBufferImageCopy region;
        memset(&region, 0, sizeof(VkBufferImageCopy));
        region.bufferOffset = 0;
        region.bufferRowLength = width;
        region.bufferImageHeight = height;
        region.imageSubresource = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 0, 1 };
        region.imageOffset = offset;
        region.imageExtent = { (uint32_t)width, (uint32_t)height, 1 };

        // Change layout of our target so it can be copied to
        VkImageLayout layout = tex->currentLayout();
        VkPipelineStageFlags srcStageMask = GrVkMemory::LayoutToPipelineStageFlags(layout);
        VkPipelineStageFlags dstStageMask = VK_PIPELINE_STAGE_TRANSFER_BIT;
        VkAccessFlags srcAccessMask = GrVkMemory::LayoutToSrcAccessMask(layout);
        VkAccessFlags dstAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;
        tex->setImageLayout(this,
                            VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
                            srcAccessMask,
                            dstAccessMask,
                            srcStageMask,
                            dstStageMask,
                            false);

        // Copy the buffer to the image
        fCurrentCmdBuffer->copyBufferToImage(this,
                                             transferBuffer,
                                             tex,
                                             VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
                                             1,
                                             &region);

        // Submit the current command buffer to the Queue
        this->submitCommandBuffer(kSkip_SyncQueue);

        transferBuffer->unref();
    }

    return true;
}

////////////////////////////////////////////////////////////////////////////////
GrTexture* GrVkGpu::onCreateTexture(const GrSurfaceDesc& desc, GrGpuResource::LifeCycle lifeCycle,
                                    const SkTArray<GrMipLevel>& texels) {
    bool renderTarget = SkToBool(desc.fFlags & kRenderTarget_GrSurfaceFlag);

    VkFormat pixelFormat;
    if (!GrPixelConfigToVkFormat(desc.fConfig, &pixelFormat)) {
        return nullptr;
    }

    if (!fVkCaps->isConfigTexturable(desc.fConfig)) {
        return nullptr;
    }

    bool linearTiling = false;
    if (SkToBool(desc.fFlags & kZeroCopy_GrSurfaceFlag)) {
        if (fVkCaps->isConfigTexurableLinearly(desc.fConfig) &&
            (!renderTarget || fVkCaps->isConfigRenderableLinearly(desc.fConfig, false))) {
            linearTiling = true;
        } else {
            return nullptr;
        }
    }

    VkImageUsageFlags usageFlags = VK_IMAGE_USAGE_SAMPLED_BIT;
    if (renderTarget) {
        usageFlags |= VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT;
    }

    // For now we will set the VK_IMAGE_USAGE_TRANSFER_DESTINATION_BIT and
    // VK_IMAGE_USAGE_TRANSFER_SOURCE_BIT on every texture since we do not know whether or not we
    // will be using this texture in some copy or not. Also this assumes, as is the current case,
    // that all render targets in vulkan are also texutres. If we change this practice of setting
    // both bits, we must make sure to set the destination bit if we are uploading srcData to the
    // texture.
    usageFlags |= VK_IMAGE_USAGE_TRANSFER_SRC_BIT | VK_IMAGE_USAGE_TRANSFER_DST_BIT;

    VkFlags memProps = (!texels.empty() && linearTiling) ? VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT :
                                                           VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT;

    // This ImageDesc refers to the texture that will be read by the client. Thus even if msaa is
    // requested, this ImageDesc describes the resolved texutre. Therefore we always have samples set
    // to 1.
    GrVkImage::ImageDesc imageDesc;
    imageDesc.fImageType = VK_IMAGE_TYPE_2D;
    imageDesc.fFormat = pixelFormat;
    imageDesc.fWidth = desc.fWidth;
    imageDesc.fHeight = desc.fHeight;
    imageDesc.fLevels = 1;
    imageDesc.fSamples = 1;
    imageDesc.fImageTiling = linearTiling ? VK_IMAGE_TILING_LINEAR : VK_IMAGE_TILING_OPTIMAL;
    imageDesc.fUsageFlags = usageFlags;
    imageDesc.fMemProps = memProps;

    GrVkTexture* tex;
    if (renderTarget) {
        tex = GrVkTextureRenderTarget::CreateNewTextureRenderTarget(this, desc, lifeCycle,
                                                                    imageDesc);
#if 0
        // This clear can be included to fix warning described in htttps://bugs.skia.org/5045
        // Obviously we do not want to be clearling needlessly every time we create a render target.
        SkIRect rect = SkIRect::MakeWH(tex->width(), tex->height());
        this->clear(rect, GrColor_TRANSPARENT_BLACK, tex->asRenderTarget());
#endif
    } else {
        tex = GrVkTexture::CreateNewTexture(this, desc, lifeCycle, imageDesc);
    }

    if (!tex) {
        return nullptr;
    }

    // TODO: We're ignoring MIP levels here.
    if (!texels.empty() && texels.begin()->fPixels) {
        if (!this->uploadTexData(tex, 0, 0, desc.fWidth, desc.fHeight, desc.fConfig,
                                 texels.begin()->fPixels, texels.begin()->fRowBytes)) {
            tex->unref();
            return nullptr;
        }
    }

    return tex;
}

////////////////////////////////////////////////////////////////////////////////

static GrSurfaceOrigin resolve_origin(GrSurfaceOrigin origin) {
    // By default, all textures in Vk use TopLeft
    if (kDefault_GrSurfaceOrigin == origin) {
        return kTopLeft_GrSurfaceOrigin;
    } else {
        return origin;
    }
}

GrTexture* GrVkGpu::onWrapBackendTexture(const GrBackendTextureDesc& desc,
                                         GrWrapOwnership ownership) {
    VkFormat format;
    if (!GrPixelConfigToVkFormat(desc.fConfig, &format)) {
        return nullptr;
    }

    if (0 == desc.fTextureHandle) {
        return nullptr;
    }

    int maxSize = this->caps()->maxTextureSize();
    if (desc.fWidth > maxSize || desc.fHeight > maxSize) {
        return nullptr;
    }

    // TODO: determine what format Chrome will actually send us and turn it into a Resource
    GrVkImage::Resource* imageRsrc = reinterpret_cast<GrVkImage::Resource*>(desc.fTextureHandle);

    GrGpuResource::LifeCycle lifeCycle;
    switch (ownership) {
        case kAdopt_GrWrapOwnership:
            lifeCycle = GrGpuResource::kAdopted_LifeCycle;
            break;
        case kBorrow_GrWrapOwnership:
            lifeCycle = GrGpuResource::kBorrowed_LifeCycle;
            break;
    }

    GrSurfaceDesc surfDesc;
    // next line relies on GrBackendTextureDesc's flags matching GrTexture's
    surfDesc.fFlags = (GrSurfaceFlags)desc.fFlags;
    surfDesc.fWidth = desc.fWidth;
    surfDesc.fHeight = desc.fHeight;
    surfDesc.fConfig = desc.fConfig;
    surfDesc.fSampleCnt = SkTMin(desc.fSampleCnt, this->caps()->maxSampleCount());
    bool renderTarget = SkToBool(desc.fFlags & kRenderTarget_GrBackendTextureFlag);
    // In GL, Chrome assumes all textures are BottomLeft
    // In VK, we don't have this restriction
    surfDesc.fOrigin = resolve_origin(desc.fOrigin);

    GrVkTexture* texture = nullptr;
    if (renderTarget) {
        texture = GrVkTextureRenderTarget::CreateWrappedTextureRenderTarget(this, surfDesc, 
                                                                            lifeCycle, format,
                                                                            imageRsrc);
    } else {
        texture = GrVkTexture::CreateWrappedTexture(this, surfDesc, lifeCycle, format, imageRsrc);
    }
    if (!texture) {
        return nullptr;
    }

    return texture;
}

GrRenderTarget* GrVkGpu::onWrapBackendRenderTarget(const GrBackendRenderTargetDesc& wrapDesc,
                                                   GrWrapOwnership ownership) {
    
    // TODO: determine what format Chrome will actually send us and turn it into a Resource
    GrVkImage::Resource* imageRsrc =
        reinterpret_cast<GrVkImage::Resource*>(wrapDesc.fRenderTargetHandle);

    GrGpuResource::LifeCycle lifeCycle;
    switch (ownership) {
        case kAdopt_GrWrapOwnership:
            lifeCycle = GrGpuResource::kAdopted_LifeCycle;
            break;
        case kBorrow_GrWrapOwnership:
            lifeCycle = GrGpuResource::kBorrowed_LifeCycle;
            break;
    }

    GrSurfaceDesc desc;
    desc.fConfig = wrapDesc.fConfig;
    desc.fFlags = kCheckAllocation_GrSurfaceFlag;
    desc.fWidth = wrapDesc.fWidth;
    desc.fHeight = wrapDesc.fHeight;
    desc.fSampleCnt = SkTMin(wrapDesc.fSampleCnt, this->caps()->maxSampleCount());

    desc.fOrigin = resolve_origin(wrapDesc.fOrigin);

    GrVkRenderTarget* tgt = GrVkRenderTarget::CreateWrappedRenderTarget(this, desc,
                                                                        lifeCycle, imageRsrc);
    if (tgt && wrapDesc.fStencilBits) {
        if (!createStencilAttachmentForRenderTarget(tgt, desc.fWidth, desc.fHeight)) {
            tgt->unref();
            return nullptr;
        }
    }
    return tgt;
}

////////////////////////////////////////////////////////////////////////////////

void GrVkGpu::bindGeometry(const GrPrimitiveProcessor& primProc,
                           const GrNonInstancedVertices& vertices) {
    GrVkVertexBuffer* vbuf;
    vbuf = (GrVkVertexBuffer*)vertices.vertexBuffer();
    SkASSERT(vbuf);
    SkASSERT(!vbuf->isMapped());

    vbuf->addMemoryBarrier(this,
                           VK_ACCESS_HOST_WRITE_BIT,
                           VK_ACCESS_VERTEX_ATTRIBUTE_READ_BIT,
                           VK_PIPELINE_STAGE_HOST_BIT,
                           VK_PIPELINE_STAGE_VERTEX_INPUT_BIT,
                           false);

    fCurrentCmdBuffer->bindVertexBuffer(this, vbuf);

    if (vertices.isIndexed()) {
        GrVkIndexBuffer* ibuf = (GrVkIndexBuffer*)vertices.indexBuffer();
        SkASSERT(ibuf);
        SkASSERT(!ibuf->isMapped());

        ibuf->addMemoryBarrier(this,
                               VK_ACCESS_HOST_WRITE_BIT,
                               VK_ACCESS_INDEX_READ_BIT,
                               VK_PIPELINE_STAGE_HOST_BIT,
                               VK_PIPELINE_STAGE_VERTEX_INPUT_BIT,
                               false);

        fCurrentCmdBuffer->bindIndexBuffer(this, ibuf);
    }
}

void GrVkGpu::buildProgramDesc(GrProgramDesc* desc,
                               const GrPrimitiveProcessor& primProc,
                               const GrPipeline& pipeline) const {
    if (!GrVkProgramDescBuilder::Build(desc, primProc, pipeline, *this->vkCaps().glslCaps())) {
        SkDEBUGFAIL("Failed to generate GL program descriptor");
    }
}

////////////////////////////////////////////////////////////////////////////////

GrStencilAttachment* GrVkGpu::createStencilAttachmentForRenderTarget(const GrRenderTarget* rt,
                                                                     int width,
                                                                     int height) {
    SkASSERT(rt->asTexture());
    SkASSERT(width >= rt->width());
    SkASSERT(height >= rt->height());

    int samples = rt->numStencilSamples();

    SkASSERT(this->vkCaps().stencilFormats().count());
    const GrVkCaps::StencilFormat& sFmt = this->vkCaps().stencilFormats()[0];

    GrVkStencilAttachment* stencil(GrVkStencilAttachment::Create(this,
                                                                 GrGpuResource::kCached_LifeCycle,
                                                                 width,
                                                                 height,
                                                                 samples,
                                                                 sFmt));
    fStats.incStencilAttachmentCreates();
    return stencil;
}

////////////////////////////////////////////////////////////////////////////////

GrBackendObject GrVkGpu::createTestingOnlyBackendTexture(void* srcData, int w, int h,
                                                         GrPixelConfig config) {

    VkFormat pixelFormat;
    if (!GrPixelConfigToVkFormat(config, &pixelFormat)) {
        return 0;
    }

    bool linearTiling = false;
    if (!fVkCaps->isConfigTexturable(config)) {
        return 0;
    }

    if (fVkCaps->isConfigTexurableLinearly(config)) {
        linearTiling = true;
    }

    // Currently this is not supported since it requires a copy which has not yet been implemented.
    if (srcData && !linearTiling) {
        return 0;
    }

    VkImageUsageFlags usageFlags = VK_IMAGE_USAGE_SAMPLED_BIT;
    usageFlags |= VK_IMAGE_USAGE_TRANSFER_SRC_BIT;
    usageFlags |= VK_IMAGE_USAGE_TRANSFER_DST_BIT;

    VkFlags memProps = (srcData && linearTiling) ? VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT :
                                                   VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT;

    // This ImageDesc refers to the texture that will be read by the client. Thus even if msaa is
    // requested, this ImageDesc describes the resolved texutre. Therefore we always have samples set
    // to 1.
    GrVkImage::ImageDesc imageDesc;
    imageDesc.fImageType = VK_IMAGE_TYPE_2D;
    imageDesc.fFormat = pixelFormat;
    imageDesc.fWidth = w;
    imageDesc.fHeight = h;
    imageDesc.fLevels = 1;
    imageDesc.fSamples = 1;
    imageDesc.fImageTiling = linearTiling ? VK_IMAGE_TILING_LINEAR : VK_IMAGE_TILING_OPTIMAL;
    imageDesc.fUsageFlags = usageFlags;
    imageDesc.fMemProps = memProps;

    const GrVkImage::Resource* imageRsrc = GrVkImage::CreateResource(this, imageDesc);
    if (!imageRsrc) {
        return 0;
    }

    if (srcData) {
        if (linearTiling) {
            const VkImageSubresource subres = {
                VK_IMAGE_ASPECT_COLOR_BIT,
                0,  // mipLevel
                0,  // arraySlice
            };
            VkSubresourceLayout layout;
            VkResult err;

            const GrVkInterface* interface = this->vkInterface();

            GR_VK_CALL(interface, GetImageSubresourceLayout(fDevice,
                                                            imageRsrc->fImage,
                                                            &subres,
                                                            &layout));

            void* mapPtr;
            err = GR_VK_CALL(interface, MapMemory(fDevice,
                                                  imageRsrc->fAlloc,
                                                  0,
                                                  layout.rowPitch * h,
                                                  0,
                                                  &mapPtr));
            if (err) {
                imageRsrc->unref(this);
                return 0;
            }

            size_t bpp = GrBytesPerPixel(config);
            size_t rowCopyBytes = bpp * w;
            // If there is no padding on dst (layout.rowPitch) we can do a single memcopy.
            // This assumes the srcData comes in with no padding.
            if (rowCopyBytes == layout.rowPitch) {
                memcpy(mapPtr, srcData, rowCopyBytes * h);
            } else {
                SkRectMemcpy(mapPtr, layout.rowPitch, srcData, w, rowCopyBytes, h);
            }
            GR_VK_CALL(interface, UnmapMemory(fDevice, imageRsrc->fAlloc));
        } else {
            // TODO: Add support for copying to optimal tiling
            SkASSERT(false);
        }
    }

    return (GrBackendObject)imageRsrc;
}

bool GrVkGpu::isTestingOnlyBackendTexture(GrBackendObject id) const {
    GrVkImage::Resource* backend = reinterpret_cast<GrVkImage::Resource*>(id);

    if (backend && backend->fImage && backend->fAlloc) {
        VkMemoryRequirements req;
        memset(&req, 0, sizeof(req));
        GR_VK_CALL(this->vkInterface(), GetImageMemoryRequirements(fDevice,
                                                                   backend->fImage,
                                                                   &req));
        // TODO: find a better check
        // This will probably fail with a different driver
        return (req.size > 0) && (req.size <= 8192 * 8192);
    }

    return false;
}

void GrVkGpu::deleteTestingOnlyBackendTexture(GrBackendObject id, bool abandon) {
    GrVkImage::Resource* backend = reinterpret_cast<GrVkImage::Resource*>(id);

    if (backend) {
        if (!abandon) {
            backend->unref(this);
        } else {
            backend->unrefAndAbandon();
        }
    }
}

////////////////////////////////////////////////////////////////////////////////

void GrVkGpu::addMemoryBarrier(VkPipelineStageFlags srcStageMask,
                               VkPipelineStageFlags dstStageMask,
                               bool byRegion,
                               VkMemoryBarrier* barrier) const {
    SkASSERT(fCurrentCmdBuffer);
    fCurrentCmdBuffer->pipelineBarrier(this,
                                       srcStageMask,
                                       dstStageMask,
                                       byRegion,
                                       GrVkCommandBuffer::kMemory_BarrierType,
                                       barrier);
}

void GrVkGpu::addBufferMemoryBarrier(VkPipelineStageFlags srcStageMask,
                                     VkPipelineStageFlags dstStageMask,
                                     bool byRegion,
                                     VkBufferMemoryBarrier* barrier) const {
    SkASSERT(fCurrentCmdBuffer);
    fCurrentCmdBuffer->pipelineBarrier(this,
                                       srcStageMask,
                                       dstStageMask,
                                       byRegion,
                                       GrVkCommandBuffer::kBufferMemory_BarrierType,
                                       barrier);
}

void GrVkGpu::addImageMemoryBarrier(VkPipelineStageFlags srcStageMask,
                                    VkPipelineStageFlags dstStageMask,
                                    bool byRegion,
                                    VkImageMemoryBarrier* barrier) const {
    SkASSERT(fCurrentCmdBuffer);
    fCurrentCmdBuffer->pipelineBarrier(this,
                                       srcStageMask,
                                       dstStageMask,
                                       byRegion,
                                       GrVkCommandBuffer::kImageMemory_BarrierType,
                                       barrier);
}

void GrVkGpu::finishDrawTarget() {
    // Submit the current command buffer to the Queue
    this->submitCommandBuffer(kSkip_SyncQueue);
}

void GrVkGpu::clearStencil(GrRenderTarget* target) {
    if (nullptr == target) {
        return;
    }
    GrStencilAttachment* stencil = target->renderTargetPriv().getStencilAttachment();
    GrVkStencilAttachment* vkStencil = (GrVkStencilAttachment*)stencil;


    VkClearDepthStencilValue vkStencilColor;
    memset(&vkStencilColor, 0, sizeof(VkClearDepthStencilValue));

    VkImageLayout origDstLayout = vkStencil->currentLayout();

    VkPipelineStageFlags srcStageMask = GrVkMemory::LayoutToPipelineStageFlags(origDstLayout);
    VkPipelineStageFlags dstStageMask = VK_PIPELINE_STAGE_TRANSFER_BIT;

    VkAccessFlags srcAccessMask = GrVkMemory::LayoutToSrcAccessMask(origDstLayout);;
    VkAccessFlags dstAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;

    vkStencil->setImageLayout(this,
                              VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
                              srcAccessMask,
                              dstAccessMask,
                              srcStageMask,
                              dstStageMask,
                              false);


    VkImageSubresourceRange subRange;
    memset(&subRange, 0, sizeof(VkImageSubresourceRange));
    subRange.aspectMask = VK_IMAGE_ASPECT_STENCIL_BIT;
    subRange.baseMipLevel = 0;
    subRange.levelCount = 1;
    subRange.baseArrayLayer = 0;
    subRange.layerCount = 1;

    // TODO: I imagine that most times we want to clear a stencil it will be at the beginning of a
    // draw. Thus we should look into using the load op functions on the render pass to clear out
    // the stencil there.
    fCurrentCmdBuffer->clearDepthStencilImage(this, vkStencil, &vkStencilColor, 1, &subRange);
}

void GrVkGpu::onClearStencilClip(GrRenderTarget* target, const SkIRect& rect, bool insideClip) {
    SkASSERT(target);

    GrVkRenderTarget* vkRT = static_cast<GrVkRenderTarget*>(target);
    GrStencilAttachment* sb = target->renderTargetPriv().getStencilAttachment();
    GrVkStencilAttachment* vkStencil = (GrVkStencilAttachment*)sb;

    // this should only be called internally when we know we have a
    // stencil buffer.
    SkASSERT(sb);
    int stencilBitCount = sb->bits();

    // The contract with the callers does not guarantee that we preserve all bits in the stencil
    // during this clear. Thus we will clear the entire stencil to the desired value.

    VkClearDepthStencilValue vkStencilColor;
    memset(&vkStencilColor, 0, sizeof(VkClearDepthStencilValue));
    if (insideClip) {
        vkStencilColor.stencil = (1 << (stencilBitCount - 1));
    } else {
        vkStencilColor.stencil = 0;
    }

    VkImageLayout origDstLayout = vkStencil->currentLayout();
    VkAccessFlags srcAccessMask = GrVkMemory::LayoutToSrcAccessMask(origDstLayout);
    VkAccessFlags dstAccessMask = VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT;
    VkPipelineStageFlags srcStageMask =
        GrVkMemory::LayoutToPipelineStageFlags(origDstLayout);
    VkPipelineStageFlags dstStageMask = VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT;
    vkStencil->setImageLayout(this,
                              VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL,
                              srcAccessMask,
                              dstAccessMask,
                              srcStageMask,
                              dstStageMask,
                              false);

    VkClearRect clearRect;
    // Flip rect if necessary
    SkIRect vkRect = rect;

    if (kBottomLeft_GrSurfaceOrigin == vkRT->origin()) {
        vkRect.fTop = vkRT->height() - rect.fBottom;
        vkRect.fBottom = vkRT->height() - rect.fTop;
    }

    clearRect.rect.offset = { vkRect.fLeft, vkRect.fTop };
    clearRect.rect.extent = { (uint32_t)vkRect.width(), (uint32_t)vkRect.height() };

    clearRect.baseArrayLayer = 0;
    clearRect.layerCount = 1;

    const GrVkRenderPass* renderPass = vkRT->simpleRenderPass();
    SkASSERT(renderPass);
    fCurrentCmdBuffer->beginRenderPass(this, renderPass, *vkRT);

    uint32_t stencilIndex;
    SkAssertResult(renderPass->stencilAttachmentIndex(&stencilIndex));

    VkClearAttachment attachment;
    attachment.aspectMask = VK_IMAGE_ASPECT_STENCIL_BIT;
    attachment.colorAttachment = 0; // this value shouldn't matter
    attachment.clearValue.depthStencil = vkStencilColor;

    fCurrentCmdBuffer->clearAttachments(this, 1, &attachment, 1, &clearRect);
    fCurrentCmdBuffer->endRenderPass(this);

    return;
}

void GrVkGpu::onClear(GrRenderTarget* target, const SkIRect& rect, GrColor color) {
    // parent class should never let us get here with no RT
    SkASSERT(target);

    VkClearColorValue vkColor;
    GrColorToRGBAFloat(color, vkColor.float32);
   
    GrVkRenderTarget* vkRT = static_cast<GrVkRenderTarget*>(target);
    VkImageLayout origDstLayout = vkRT->currentLayout();

    if (rect.width() != target->width() || rect.height() != target->height()) {
        VkAccessFlags srcAccessMask = GrVkMemory::LayoutToSrcAccessMask(origDstLayout);
        VkAccessFlags dstAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
        VkPipelineStageFlags srcStageMask =
            GrVkMemory::LayoutToPipelineStageFlags(origDstLayout);
        VkPipelineStageFlags dstStageMask = VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT;
        vkRT->setImageLayout(this,
                             VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL,
                             srcAccessMask,
                             dstAccessMask,
                             srcStageMask,
                             dstStageMask,
                             false);

        VkClearRect clearRect;
        // Flip rect if necessary
        SkIRect vkRect = rect;
        if (kBottomLeft_GrSurfaceOrigin == vkRT->origin()) {
            vkRect.fTop = vkRT->height() - rect.fBottom;
            vkRect.fBottom = vkRT->height() - rect.fTop;
        }
        clearRect.rect.offset = { vkRect.fLeft, vkRect.fTop };
        clearRect.rect.extent = { (uint32_t)vkRect.width(), (uint32_t)vkRect.height() };
        clearRect.baseArrayLayer = 0;
        clearRect.layerCount = 1;

        const GrVkRenderPass* renderPass = vkRT->simpleRenderPass();
        SkASSERT(renderPass);
        fCurrentCmdBuffer->beginRenderPass(this, renderPass, *vkRT);

        uint32_t colorIndex;
        SkAssertResult(renderPass->colorAttachmentIndex(&colorIndex));

        VkClearAttachment attachment;
        attachment.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
        attachment.colorAttachment = colorIndex;
        attachment.clearValue.color = vkColor;

        fCurrentCmdBuffer->clearAttachments(this, 1, &attachment, 1, &clearRect);
        fCurrentCmdBuffer->endRenderPass(this);
        return;
    }

    VkPipelineStageFlags srcStageMask = GrVkMemory::LayoutToPipelineStageFlags(origDstLayout);
    VkPipelineStageFlags dstStageMask = VK_PIPELINE_STAGE_TRANSFER_BIT;

    VkAccessFlags srcAccessMask = GrVkMemory::LayoutToSrcAccessMask(origDstLayout);;
    VkAccessFlags dstAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;

    vkRT->setImageLayout(this,
                         VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
                         srcAccessMask,
                         dstAccessMask,
                         srcStageMask,
                         dstStageMask,
                         false);


    VkImageSubresourceRange subRange;
    memset(&subRange, 0, sizeof(VkImageSubresourceRange));
    subRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
    subRange.baseMipLevel = 0;
    subRange.levelCount = 1;
    subRange.baseArrayLayer = 0;
    subRange.layerCount = 1;

    // In the future we may not actually be doing this type of clear at all. If we are inside a 
    // render pass or doing a non full clear then we will use CmdClearColorAttachment. The more
    // common use case will be clearing an attachment at the start of a render pass, in which case
    // we will use the clear load ops.
    fCurrentCmdBuffer->clearColorImage(this,
                                       vkRT,
                                       &vkColor,
                                       1, &subRange);
}

inline bool can_copy_image(const GrSurface* dst,
                           const GrSurface* src,
                           const GrVkGpu* gpu) {
    if (src->asTexture() &&
        dst->asTexture() &&
        src->origin() == dst->origin() &&
        src->config() == dst->config()) {
        return true;
    }

    // How does msaa play into this? If a VkTexture is multisampled, are we copying the multisampled
    // or the resolved image here?

    return false;
}

void GrVkGpu::copySurfaceAsCopyImage(GrSurface* dst,
                                     GrSurface* src,
                                     const SkIRect& srcRect,
                                     const SkIPoint& dstPoint) {
    SkASSERT(can_copy_image(dst, src, this));

    // Insert memory barriers to switch src and dst to transfer_source and transfer_dst layouts
    GrVkTexture* dstTex = static_cast<GrVkTexture*>(dst->asTexture());
    GrVkTexture* srcTex = static_cast<GrVkTexture*>(src->asTexture());

    VkImageLayout origDstLayout = dstTex->currentLayout();
    VkImageLayout origSrcLayout = srcTex->currentLayout();

    VkPipelineStageFlags srcStageMask = GrVkMemory::LayoutToPipelineStageFlags(origDstLayout);
    VkPipelineStageFlags dstStageMask = VK_PIPELINE_STAGE_TRANSFER_BIT;

    // These flags are for flushing/invalidating caches and for the dst image it doesn't matter if
    // the cache is flushed since it is only being written to.
    VkAccessFlags srcAccessMask = GrVkMemory::LayoutToSrcAccessMask(origDstLayout);;
    VkAccessFlags dstAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;
    
    dstTex->setImageLayout(this,
                           VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
                           srcAccessMask,
                           dstAccessMask,
                           srcStageMask,
                           dstStageMask,
                           false);
    
    srcStageMask = GrVkMemory::LayoutToPipelineStageFlags(origSrcLayout);
    dstStageMask = VK_PIPELINE_STAGE_TRANSFER_BIT;

    srcAccessMask = GrVkMemory::LayoutToSrcAccessMask(origSrcLayout);
    dstAccessMask = VK_ACCESS_TRANSFER_READ_BIT;

    srcTex->setImageLayout(this,
                           VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL,
                           srcAccessMask,
                           dstAccessMask,
                           srcStageMask,
                           dstStageMask,
                           false);

    // Flip rect if necessary
    SkIRect srcVkRect = srcRect;
    int32_t dstY = dstPoint.fY;

    if (kBottomLeft_GrSurfaceOrigin == src->origin()) {
        SkASSERT(kBottomLeft_GrSurfaceOrigin == dst->origin());
        srcVkRect.fTop = src->height() - srcRect.fBottom;
        srcVkRect.fBottom =  src->height() - srcRect.fTop;
        dstY = dst->height() - dstPoint.fY - srcVkRect.height();
    }

    VkImageCopy copyRegion;
    memset(&copyRegion, 0, sizeof(VkImageCopy));
    copyRegion.srcSubresource = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 0, 1 };
    copyRegion.srcOffset = { srcVkRect.fLeft, srcVkRect.fTop, 0 };
    copyRegion.dstSubresource = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 0, 1 };
    copyRegion.dstOffset = { dstPoint.fX, dstY, 0 };
    copyRegion.extent = { (uint32_t)srcVkRect.width(), (uint32_t)srcVkRect.height(), 0 };

    fCurrentCmdBuffer->copyImage(this,
                                 srcTex,
                                 VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL,
                                 dstTex,
                                 VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
                                 1,
                                 &copyRegion);
}

inline bool can_copy_as_draw(const GrSurface* dst,
                             const GrSurface* src,
                             const GrVkGpu* gpu) {
    return false;
}

void GrVkGpu::copySurfaceAsDraw(GrSurface* dst,
                                GrSurface* src,
                                const SkIRect& srcRect,
                                const SkIPoint& dstPoint) {
    SkASSERT(false);
}

bool GrVkGpu::onCopySurface(GrSurface* dst,
                            GrSurface* src,
                            const SkIRect& srcRect,
                            const SkIPoint& dstPoint) {
    if (can_copy_image(dst, src, this)) {
        this->copySurfaceAsCopyImage(dst, src, srcRect, dstPoint);
        return true;
    }

    if (can_copy_as_draw(dst, src, this)) {
        this->copySurfaceAsDraw(dst, src, srcRect, dstPoint);
        return true;
    }

    return false;
}

void GrVkGpu::onGetMultisampleSpecs(GrRenderTarget* rt, const GrStencilSettings&,
                                    int* effectiveSampleCnt, SkAutoTDeleteArray<SkPoint>*) {
    // TODO: stub.
    SkASSERT(!this->caps()->sampleLocationsSupport());
    *effectiveSampleCnt = rt->desc().fSampleCnt;
}

bool GrVkGpu::onGetReadPixelsInfo(GrSurface* srcSurface, int width, int height, size_t rowBytes,
                                  GrPixelConfig readConfig, DrawPreference* drawPreference,
                                  ReadPixelTempDrawInfo* tempDrawInfo) {
    // Currently we don't handle draws, so if the caller wants/needs to do a draw we need to fail
    if (kNoDraw_DrawPreference != *drawPreference) {
        return false;
    }

    if (srcSurface->config() != readConfig) {
        // TODO: This should fall back to drawing or copying to change config of srcSurface to match
        // that of readConfig.
        return false;
    }

    return true;
}

bool GrVkGpu::onReadPixels(GrSurface* surface,
                           int left, int top, int width, int height,
                           GrPixelConfig config,
                           void* buffer,
                           size_t rowBytes) {
    VkFormat pixelFormat;
    if (!GrPixelConfigToVkFormat(config, &pixelFormat)) {
        return false;
    }

    GrVkTexture* tgt = static_cast<GrVkTexture*>(surface->asTexture());
    if (!tgt) {
        return false;
    }

    // Change layout of our target so it can be used as copy
    VkImageLayout layout = tgt->currentLayout();
    VkPipelineStageFlags srcStageMask = GrVkMemory::LayoutToPipelineStageFlags(layout);
    VkPipelineStageFlags dstStageMask = VK_PIPELINE_STAGE_TRANSFER_BIT;
    VkAccessFlags srcAccessMask = GrVkMemory::LayoutToSrcAccessMask(layout);
    VkAccessFlags dstAccessMask = VK_ACCESS_TRANSFER_READ_BIT;
    tgt->setImageLayout(this,
                        VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL,
                        srcAccessMask,
                        dstAccessMask,
                        srcStageMask,
                        dstStageMask,
                        false);

    GrVkTransferBuffer* transferBuffer = 
        reinterpret_cast<GrVkTransferBuffer*>(this->createTransferBuffer(rowBytes * height, 
                                                                         kGpuToCpu_TransferType));

    bool flipY = kBottomLeft_GrSurfaceOrigin == surface->origin();
    VkOffset3D offset = {
        left,
        flipY ? surface->height() - top - height : top,
        0
    };

    // Copy the image to a buffer so we can map it to cpu memory
    VkBufferImageCopy region;
    memset(&region, 0, sizeof(VkBufferImageCopy));
    region.bufferOffset = 0;
    region.bufferRowLength = 0; // Forces RowLength to be imageExtent.width
    region.bufferImageHeight = 0; // Forces height to be tightly packed. Only useful for 3d images.
    region.imageSubresource = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 0, 1 };
    region.imageOffset = offset;
    region.imageExtent = { (uint32_t)width, (uint32_t)height, 1 };

    fCurrentCmdBuffer->copyImageToBuffer(this,
                                         tgt,
                                         VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL,
                                         transferBuffer,
                                         1,
                                         &region);

    // make sure the copy to buffer has finished
    transferBuffer->addMemoryBarrier(this,
                                     VK_ACCESS_TRANSFER_WRITE_BIT,
                                     VK_ACCESS_HOST_READ_BIT,
                                     VK_PIPELINE_STAGE_TRANSFER_BIT,
                                     VK_PIPELINE_STAGE_HOST_BIT,
                                     false);

    // We need to submit the current command buffer to the Queue and make sure it finishes before
    // we can copy the data out of the buffer.
    this->submitCommandBuffer(kForce_SyncQueue);

    void* mappedMemory = transferBuffer->map();

    memcpy(buffer, mappedMemory, rowBytes*height);

    transferBuffer->unmap();
    transferBuffer->unref();

    if (flipY) {
        SkAutoSMalloc<32 * sizeof(GrColor)> scratch;
        size_t tightRowBytes = GrBytesPerPixel(config) * width;
        scratch.reset(tightRowBytes);
        void* tmpRow = scratch.get();
        // flip y in-place by rows
        const int halfY = height >> 1;
        char* top = reinterpret_cast<char*>(buffer);
        char* bottom = top + (height - 1) * rowBytes;
        for (int y = 0; y < halfY; y++) {
            memcpy(tmpRow, top, tightRowBytes);
            memcpy(top, bottom, tightRowBytes);
            memcpy(bottom, tmpRow, tightRowBytes);
            top += rowBytes;
            bottom -= rowBytes;
        }
    }

    return true;
}

void GrVkGpu::onDraw(const DrawArgs& args, const GrNonInstancedVertices& vertices) {
    GrRenderTarget* rt = args.fPipeline->getRenderTarget();
    GrVkRenderTarget* vkRT = static_cast<GrVkRenderTarget*>(rt);
    const GrVkRenderPass* renderPass = vkRT->simpleRenderPass();
    SkASSERT(renderPass);

    GrVkProgram* program = GrVkProgramBuilder::CreateProgram(this, args,
                                                             vertices.primitiveType(),
                                                             *renderPass);

    if (!program) {
        return;
    }

    program->setData(this, *args.fPrimitiveProcessor, *args.fPipeline);

    fCurrentCmdBuffer->beginRenderPass(this, renderPass, *vkRT);

    program->bind(this, fCurrentCmdBuffer);

    this->bindGeometry(*args.fPrimitiveProcessor, vertices);

    // Change layout of our render target so it can be used as the color attachment
    VkImageLayout layout = vkRT->currentLayout();
    // Our color attachment is purely a destination and won't be read so don't need to flush or
    // invalidate any caches
    VkPipelineStageFlags srcStageMask = GrVkMemory::LayoutToPipelineStageFlags(layout);
    VkPipelineStageFlags dstStageMask = VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT;
    VkAccessFlags srcAccessMask = GrVkMemory::LayoutToSrcAccessMask(layout);
    VkAccessFlags dstAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
    vkRT->setImageLayout(this,
                         VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL,
                         srcAccessMask,
                         dstAccessMask,
                         srcStageMask,
                         dstStageMask,
                         false);

    // If we are using a stencil attachment we also need to update its layout
    if (!args.fPipeline->getStencil().isDisabled()) {
        GrStencilAttachment* stencil = vkRT->renderTargetPriv().getStencilAttachment();
        GrVkStencilAttachment* vkStencil = (GrVkStencilAttachment*)stencil;
        VkImageLayout origDstLayout = vkStencil->currentLayout();
        VkAccessFlags srcAccessMask = GrVkMemory::LayoutToSrcAccessMask(origDstLayout);
        VkAccessFlags dstAccessMask = VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT |
                                      VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_READ_BIT;
        VkPipelineStageFlags srcStageMask =
            GrVkMemory::LayoutToPipelineStageFlags(origDstLayout);
        VkPipelineStageFlags dstStageMask = VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT;
        vkStencil->setImageLayout(this,
                                  VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL,
                                  srcAccessMask,
                                  dstAccessMask,
                                  srcStageMask,
                                  dstStageMask,
                                  false);
    }

    if (vertices.isIndexed()) {
        fCurrentCmdBuffer->drawIndexed(this,
                                       vertices.indexCount(),
                                       1,
                                       vertices.startIndex(),
                                       vertices.startVertex(),
                                       0);
    } else {
        fCurrentCmdBuffer->draw(this, vertices.vertexCount(), 1, vertices.startVertex(),  0);
    }

    fCurrentCmdBuffer->endRenderPass(this);

    // Technically we don't have to call this here (since there is a safety check in program:setData
    // but this will allow for quicker freeing of resources if the program sits in a cache for a
    // while.
    program->freeTempResources(this);
    // This free will go away once we setup a program cache, and then the cache will be responsible
    // for call freeGpuResources.
    program->freeGPUResources(this);
    program->unref();

#if SWAP_PER_DRAW
    glFlush();
#if defined(SK_BUILD_FOR_MAC)
    aglSwapBuffers(aglGetCurrentContext());
    int set_a_break_pt_here = 9;
    aglSwapBuffers(aglGetCurrentContext());
#elif defined(SK_BUILD_FOR_WIN32)
    SwapBuf();
    int set_a_break_pt_here = 9;
    SwapBuf();
#endif
#endif
}