CD3DX12_DESCRIPTOR_RANGE1
的baseShaderRegister
用来指定 t0 t1 b0 b1...的index
t0 srv
b0 constant buffer
u0 uav
这个的名字叫 hlsl bind slot
还有个index 叫 API bind slot
pCmdList->SetComputeRoot32BitConstant(0,seed); // 0 is the parameter index,--api bind slot
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Descriptor GPU资源的描述信息
Descriptor Heaps
Descriptor Tables
可以快速申请，因为只是标记（memory 地址）
CD3DX12_DESCRIPTOR_RANGE1 DescRange[6]; DescRange[0].Init(D3D12_DESCRIPTOR_RANGE_SRV,6,2); // t2-t7
DescRange[1].Init(D3D12_DESCRIPTOR_RANGE_UAV,4,0); // u0-u3
DescRange[2].Init(D3D12_DESCRIPTOR_RANGE_SAMPLER,2,0); // s0-s1
CD3DX12_ROOT_PARAMETER1 RP[7]; RP[0].InitAsConstants(3,2); // 3 constants at b2
RP[1].InitAsDescriptorTable(2,&DescRange[0]); // 2 ranges t2-t7 and u0-u3
CD3DX12_STATIC_SAMPLER StaticSamplers[1];
StaticSamplers[0].Init(3, D3D12_FILTER_ANISOTROPIC); // s3
CD3DX12_STATIC_SAMPLER StaticSamplers[1];
StaticSamplers[0].Init(3, D3D12_FILTER_ANISOTROPIC); // s3
CD3DX12_VERSIONED_ROOT_SIGNATURE_DESC RootSig(7,RP,1,StaticSamplers);
ID3DBlob* pSerializedRootSig;
CheckHR(D3D12SerializeVersionedRootSignature(&RootSig,pSerializedRootSig));
ID3D12RootSignature* pRootSignature;
hr = CheckHR(pDevice->CreateRootSignature( pSerializedRootSig->GetBufferPointer(),pSerializedRootSig->GetBufferSize(), __uuidof(ID3D12RootSignature), &pRootSignature));
Root Signaatures 包含 root constants, root descriptors, descriptor tables 三种类型
是shader paramaters
REF:
https://docs.microsoft.com/en-us/windows/desktop/direct3d12/descriptor-tables-overview
https://docs.microsoft.com/en-us/windows/desktop/direct3d12/creating-a-root-signature
https://www.3dgep.com/learning-directx-12-3/
https://docs.microsoft.com/en-us/windows/win32/direct3d12/descriptors
https://docs.microsoft.com/en-us/windows/win32/direct3d12/descriptors-overview
descriptors包含srv uav cbv sampler等资源
bind的时候是用descriptor来bind的
这东西就相当于metal的 argument buffer/argument table
https://docs.microsoft.com/en-us/windows/win32/direct3d12/copying-descriptors
descriptor copy是一个走cpu timeline的操作
但source不能对gpu可见 dest可以对cpu gpu都可见
所以cpu copy descriptor的时候 要等gpu把这些资源用完
https://docs.microsoft.com/en-us/windows/win32/direct3d12/resource-binding-flow-of-control
resource类型
- Constant buffer view (CBV)
- Unordered access view (UAV)
- Shader resource view (SRV)
- Samplers
- Render Target View (RTV)
- Depth Stencil View (DSV)
- Index Buffer View (IBV)
- Vertex Buffer View (VBV)
- Stream Output View (SOV)