DirectX Raytracing samples

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

//                                                                           //

// D3D12RaytracingFallback.h                                                 //

//                                                                           //

// Provides a simplified interface for the DX12 Ray Tracing interface that   //

// will use native DX12 ray tracing when available. For drivers that do not  //

// support ray tracing, a fallback compute-shader based solution will be     //

// used instead.                                                             //    

//                                                                           //

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

#pragma once

#include "d3d12_1.h"

struct EMULATED_GPU_POINTER

{

    UINT32 OffsetInBytes;

    UINT32 DescriptorHeapIndex;

};

struct WRAPPED_GPU_POINTER

{

    union

    {

        EMULATED_GPU_POINTER EmulatedGpuPtr;

        D3D12_GPU_VIRTUAL_ADDRESS GpuVA;

    };

    WRAPPED_GPU_POINTER operator+(UINT64 offset)

    {

        WRAPPED_GPU_POINTER pointer = *this;

        pointer.GpuVA += offset;

        return pointer;

    }

};

typedef struct D3D12_RAYTRACING_FALLBACK_INSTANCE_DESC

{

    FLOAT Transform[3][4];

    UINT InstanceID : 24;

    UINT InstanceMask : 8;

    UINT InstanceContributionToHitGroupIndex : 24;

    UINT Flags : 8;

    WRAPPED_GPU_POINTER AccelerationStructure;

}     D3D12_RAYTRACING_FALLBACK_INSTANCE_DESC;

class

_declspec(uuid("539e5c40-df25-4c7d-81d8-6537f54306ed"))

ID3D12RaytracingFallbackStateObject : public IUnknown

{

public:

    virtual ~ID3D12RaytracingFallbackStateObject() {};

    virtual void *STDMETHODCALLTYPE GetShaderIdentifier(

        _In_  LPCWSTR pExportName) = 0;

    virtual UINT64 STDMETHODCALLTYPE GetShaderStackSize(

        _In_  LPCWSTR pExportName) = 0;

    virtual UINT64 STDMETHODCALLTYPE GetPipelineStackSize(void) = 0;

    virtual void STDMETHODCALLTYPE SetPipelineStackSize(

        UINT64 PipelineStackSizeInBytes) = 0;

    virtual ID3D12StateObject *GetStateObject() = 0;

};

class

_declspec(uuid("348a2a6b-6760-4b78-a9a7-1758b6f78d46"))

ID3D12RaytracingFallbackCommandList : public IUnknown

{

public:

    virtual ~ID3D12RaytracingFallbackCommandList() {}

    virtual void BuildRaytracingAccelerationStructure(

        _In_  const D3D12_BUILD_RAYTRACING_ACCELERATION_STRUCTURE_DESC *pDesc,

        _In_  UINT NumPostbuildInfoDescs,

        _In_reads_opt_(NumPostbuildInfoDescs)  const D3D12_RAYTRACING_ACCELERATION_STRUCTURE_POSTBUILD_INFO_DESC *pPostbuildInfoDescs) = 0;

    virtual void STDMETHODCALLTYPE EmitRaytracingAccelerationStructurePostbuildInfo(

        _In_  const D3D12_RAYTRACING_ACCELERATION_STRUCTURE_POSTBUILD_INFO_DESC *pDesc,

        _In_  UINT NumSourceAccelerationStructures,

        _In_reads_(NumSourceAccelerationStructures)  const D3D12_GPU_VIRTUAL_ADDRESS *pSourceAccelerationStructureData) = 0;

    virtual void STDMETHODCALLTYPE CopyRaytracingAccelerationStructure(

        _In_  D3D12_GPU_VIRTUAL_ADDRESS DestAccelerationStructureData,

        _In_  D3D12_GPU_VIRTUAL_ADDRESS SourceAccelerationStructureData,

        _In_  D3D12_RAYTRACING_ACCELERATION_STRUCTURE_COPY_MODE Mode) = 0;

    virtual void STDMETHODCALLTYPE SetDescriptorHeaps(

        _In_  UINT NumDescriptorHeaps,

        _In_reads_(NumDescriptorHeaps)  ID3D12DescriptorHeap *const *ppDescriptorHeaps) = 0;

    virtual void STDMETHODCALLTYPE SetTopLevelAccelerationStructure(

        _In_  UINT RootParameterIndex,

        _In_  WRAPPED_GPU_POINTER  BufferLocation) = 0;

    virtual void STDMETHODCALLTYPE SetPipelineState1(

        _In_  ID3D12RaytracingFallbackStateObject *pStateObject) = 0;

    virtual void STDMETHODCALLTYPE DispatchRays(

        _In_  const D3D12_DISPATCH_RAYS_DESC *pDesc) = 0;

};

class

_declspec(uuid("0a662ea0-ab43-423a-848f-4824ae4b25ba"))

ID3D12RaytracingFallbackDevice : public IUnknown

{

public:

    virtual ~ID3D12RaytracingFallbackDevice() {};

    virtual bool UsingRaytracingDriver() = 0;

    // Automatically determine how to create WRAPPED_GPU_POINTER based on UsingRaytracingDriver()

    virtual WRAPPED_GPU_POINTER GetWrappedPointerSimple(UINT32 DescriptorHeapIndex, D3D12_GPU_VIRTUAL_ADDRESS GpuVA) = 0;

    // Pre-condition: UsingRaytracingDriver() must be false

    virtual WRAPPED_GPU_POINTER GetWrappedPointerFromDescriptorHeapIndex(UINT32 DescriptorHeapIndex, UINT32 OffsetInBytes = 0) = 0;

    // Pre-condition: UsingRaytracingDriver() must be true

    virtual WRAPPED_GPU_POINTER GetWrappedPointerFromGpuVA(D3D12_GPU_VIRTUAL_ADDRESS gpuVA) = 0;

    virtual D3D12_RESOURCE_STATES GetAccelerationStructureResourceState() = 0;

    virtual UINT STDMETHODCALLTYPE GetShaderIdentifierSize(void) = 0;

    virtual HRESULT STDMETHODCALLTYPE CreateStateObject(

        const D3D12_STATE_OBJECT_DESC *pDesc,

        REFIID riid,

        _COM_Outptr_  void **ppStateObject) = 0;

    virtual void STDMETHODCALLTYPE GetRaytracingAccelerationStructurePrebuildInfo(

        _In_  const D3D12_BUILD_RAYTRACING_ACCELERATION_STRUCTURE_INPUTS *pDesc,

        _Out_  D3D12_RAYTRACING_ACCELERATION_STRUCTURE_PREBUILD_INFO *pInfo) = 0;

    virtual void QueryRaytracingCommandList(

        ID3D12GraphicsCommandList *pCommandList, 

        REFIID riid,

        _COM_Outptr_  void **ppRaytracingCommandList) = 0;

    virtual HRESULT STDMETHODCALLTYPE CreateRootSignature(

        _In_  UINT nodeMask,

        _In_reads_(blobLengthInBytes)  const void *pBlobWithRootSignature,

        _In_  SIZE_T blobLengthInBytes,

        REFIID riid,

        _COM_Outptr_  void **ppvRootSignature) = 0;

    virtual HRESULT D3D12SerializeVersionedRootSignature(

        _In_ const D3D12_VERSIONED_ROOT_SIGNATURE_DESC* pRootSignature,

        _Out_ ID3DBlob** ppBlob,

        _Always_(_Outptr_opt_result_maybenull_) ID3DBlob** ppErrorBlob) = 0;

    virtual HRESULT WINAPI D3D12SerializeRootSignature(

        _In_ const D3D12_ROOT_SIGNATURE_DESC* pRootSignature,

        _In_ D3D_ROOT_SIGNATURE_VERSION Version,

        _Out_ ID3DBlob** ppBlob,

        _Always_(_Outptr_opt_result_maybenull_) ID3DBlob** ppErrorBlob) = 0;

};

enum CreateRaytracingFallbackDeviceFlags

{

    None = 0x0,

    ForceComputeFallback = 0x1,

    EnableRootDescriptorsInShaderRecords = 0x2

};

HRESULT D3D12CreateRaytracingFallbackDevice(

    _In_ ID3D12Device *pDevice, 

    _In_ DWORD createRaytracingFallbackDeviceFlags,

    _In_ UINT NodeMask,

    _In_ REFIID riid,

    _COM_Outptr_opt_ void** ppDevice);

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