Method create

Source/Falcor/Core/API/CopyContext.cpp:320–377

}

CopyContext::ReadTextureTask::SharedPtr CopyContext::ReadTextureTask::create(
    CopyContext* pCtx,
    const Texture* pTexture,
    uint32_t subresourceIndex
)
{
    SharedPtr pThis = SharedPtr(new ReadTextureTask);
    pThis->mpContext = pCtx;
    // Get footprint
    gfx::ITextureResource* srcTexture = pTexture->getGfxTextureResource();
    gfx::FormatInfo formatInfo;
    gfx::gfxGetFormatInfo(srcTexture->getDesc()->format, &formatInfo);

    auto mipLevel = pTexture->getSubresourceMipLevel(subresourceIndex);
    pThis->mActualRowSize =
        uint32_t((pTexture->getWidth(mipLevel) + formatInfo.blockWidth - 1) / formatInfo.blockWidth * formatInfo.blockSizeInBytes);
    size_t rowAlignment = 1;
    pCtx->mpDevice->getGfxDevice()->getTextureRowAlignment(&rowAlignment);
    pThis->mRowSize = align_to(static_cast<uint32_t>(rowAlignment), pThis->mActualRowSize);
    uint64_t rowCount = (pTexture->getHeight(mipLevel) + formatInfo.blockHeight - 1) / formatInfo.blockHeight;
    uint64_t size = pTexture->getDepth(mipLevel) * rowCount * pThis->mRowSize;

    // Create buffer
    pThis->mpBuffer = pCtx->getDevice()->createBuffer(size, ResourceBindFlags::None, MemoryType::ReadBack, nullptr);

    // Copy from texture to buffer
    pCtx->resourceBarrier(pTexture, Resource::State::CopySource);
    auto encoder = pCtx->getLowLevelData()->getResourceCommandEncoder();
    gfx::SubresourceRange srcSubresource = {};
    srcSubresource.baseArrayLayer = pTexture->getSubresourceArraySlice(subresourceIndex);
    srcSubresource.mipLevel = mipLevel;
    srcSubresource.layerCount = 1;
    srcSubresource.mipLevelCount = 1;
    encoder->copyTextureToBuffer(
        pThis->mpBuffer->getGfxBufferResource(),
        0,
        size,
        pThis->mRowSize,
        srcTexture,
        gfx::ResourceState::CopySource,
        srcSubresource,
        gfx::ITextureResource::Offset3D(0, 0, 0),
        gfx::ITextureResource::Extents{
            static_cast<gfx::GfxIndex>(pTexture->getWidth(mipLevel)),
            static_cast<gfx::GfxIndex>(pTexture->getHeight(mipLevel)),
            static_cast<gfx::GfxIndex>(pTexture->getDepth(mipLevel))}
    );
    pCtx->setPendingCommands(true);

    // Create a fence and signal
    pThis->mpFence = pCtx->getDevice()->createFence();
    pThis->mpFence->breakStrongReferenceToDevice();
    pCtx->submit(false);
    pCtx->signal(pThis->mpFence.get());
    pThis->mRowCount = (uint32_t)rowCount;
    pThis->mDepth = pTexture->getDepth(mipLevel);
    return pThis;
}