directml 指南

Prerequisites

DirectX 12-capable GPU drivers
Windows 10 version 1903 or newer
Windows 10 SDK version 1903

DirectML Resource

The key to resource binding in DirectX 12 are the concepts of a descriptor, descriptor tables, descriptor heaps, and a root signature. A descriptor is a small object that contains information about one resource.

typedef struct D3D12_SHADER_RESOURCE_VIEW_DESC
{
    DXGI_FORMAT Format;
    D3D12_SRV_DIMENSION ViewDimension;

    union
    {
        D3D12_BUFFER_SRV Buffer;
        D3D12_TEX1D_SRV Texture1D;
        D3D12_TEX1D_ARRAY_SRV Texture1DArray;
        D3D12_TEX2D_SRV Texture2D;
        D3D12_TEX2D_ARRAY_SRV Texture2DArray;
        D3D12_TEX2DMS_SRV Texture2DMS;
        D3D12_TEX2DMS_ARRAY_SRV Texture2DMSArray;
        D3D12_TEX3D_SRV Texture3D;
        D3D12_TEXCUBE_SRV TextureCube;
        D3D12_TEXCUBE_ARRAY_SRV TextureCubeArray;
        D3D12_BUFFEREX_SRV BufferEx;
    };
} D3D12_SHADER_RESOURCE_VIEW_DESC;

interface ID3D12Device
{
...
    void CreateShaderResourceView (
        _In_opt_ ID3D12Resource* pResource,
        _In_opt_ const D3D12_SHADER_RESOURCE_VIEW_DESC* pDesc,
        _In_ D3D12_CPU_DESCRIPTOR_HANDLE DestDescriptor);
};

// create SRV
D3D12_SHADER_RESOURCE_VIEW_DESC srvDesc;
ZeroMemory(&srvDesc, sizeof(D3D12_SHADER_RESOURCE_VIEW_DESC));
srvDesc.Format = mTexture->Format;
srvDesc.ViewDimension = D3D12_SRV_DIMENSION_TEXTURE2D;
srvDesc.Texture2D.MipLevels = 1;

mDevice->CreateShaderResourceView(mTexture.Get(), &srvDesc, mCbvSrvDescriptorHeap->GetCPUDescriptorHandleForHeapStart());

Descriptor：描述 GPU 中资源类型、数据格式、存储地址。

常见的 Descriptor 类型:
- Constant buffer views (CBVs)
- Unordered access views (UAVs)
- Shader resource views (SRVs)
- Samplers
Descriptor Table：Descriptors 分类存入 Descriptor Table
Descriptor Heap：Descriptors 存储在 Descriptor Heap 中