public unsafe void CreateShaderTable()
{
/** The shader-table layout is as follows:
* Entry 0 - Ray-gen program
* Entry 1 - Miss program
* Entry 2 - Hit program
* All entries in the shader-table must have the same size, so we will choose it base on the largest required entry.
* The ray-gen program requires the largest entry - sizeof(program identifier) + 8 bytes for a descriptor-table.
* The entry size must be aligned up to D3D12_RAYTRACING_SHADER_RECORD_BYTE_ALIGNMENT
*/
// Calculate the size and create the buffer
mShaderTableEntrySize = D3D12ShaderIdentifierSizeInBytes;
mShaderTableEntrySize += 8; // the ray-gen's descriptor table
mShaderTableEntrySize = align_to(D3D12RaytracingShaderRecordByteAlignment, mShaderTableEntrySize);
uint shaderTableSize = mShaderTableEntrySize * 4;
// For simplicity, we create the shader.table on the upload heap. You can also create it on the default heap
mpShaderTable = this.acs.CreateBuffer(mpDevice, shaderTableSize, ResourceFlags.None, ResourceStates.GenericRead, AccelerationStructures.kUploadHeapProps);
// Map the buffer
IntPtr pData;
pData = mpShaderTable.Map(0, null);
ID3D12StateObjectProperties pRtsoProps;
pRtsoProps = mpPipelineState.QueryInterface <ID3D12StateObjectProperties>();
// Entry 0 - ray-gen program ID and descriptor data
Unsafe.CopyBlock((void *)pData, (void *)pRtsoProps.GetShaderIdentifier(RTPipeline.kRayGenShader), D3D12ShaderIdentifierSizeInBytes);
ulong heapStart = (ulong)mpSrvUavHeap.GetGPUDescriptorHandleForHeapStart().Ptr;
Unsafe.Write <ulong>((pData + (int)D3D12ShaderIdentifierSizeInBytes).ToPointer(), heapStart);
// This is where we need to set the descriptor data for the ray-gen shader. We'll get to it in the next tutorial
// Entry 1 - miss program
pData += (int)mShaderTableEntrySize; // +1 skips ray-gen
Unsafe.CopyBlock((void *)pData, (void *)pRtsoProps.GetShaderIdentifier(RTPipeline.kMissShader), D3D12ShaderIdentifierSizeInBytes);
// Entry 2 - miss program
pData += (int)mShaderTableEntrySize; // +1 skips ray-gen
Unsafe.CopyBlock((void *)pData, (void *)pRtsoProps.GetShaderIdentifier(RTPipeline.kShadowMiss), D3D12ShaderIdentifierSizeInBytes);
// Entry 3 - hit program
pData += (int)mShaderTableEntrySize; // +1 skips miss entries
Unsafe.CopyBlock((void *)pData, (void *)pRtsoProps.GetShaderIdentifier(RTPipeline.kHitGroup), D3D12ShaderIdentifierSizeInBytes);
heapStart = (ulong)mpSrvUavHeap.GetGPUDescriptorHandleForHeapStart().Ptr;
Unsafe.Write <ulong>((pData + (int)D3D12ShaderIdentifierSizeInBytes).ToPointer(), heapStart);
// Unmap
mpShaderTable.Unmap(0, null);
}
public DescriptorHandle Allocate(int count)
{
if (_currentHeap == null ||
_remainingFreeHandles < count)
{
_currentHeap = Device.RequestNewHeap(Type, DescriptorsPerHeap);
_currentCpuHandle = _currentHeap.GetCPUDescriptorHandleForHeapStart();
if (IsShaderVisible)
{
_currentGpuHandle = _currentHeap.GetGPUDescriptorHandleForHeapStart();
}
_remainingFreeHandles = DescriptorsPerHeap;
if (_descriptorSize == 0)
{
_descriptorSize = Device.D3D12Device.GetDescriptorHandleIncrementSize(Type);
}
}
var cpuHandle = _currentCpuHandle;
_currentCpuHandle.Ptr += count * _descriptorSize;
_remainingFreeHandles -= count;
if (IsShaderVisible)
{
var gpuHandle = _currentGpuHandle;
_currentGpuHandle.Ptr += (long)(count * _descriptorSize);
return(new DescriptorHandle(_currentHeap, _descriptorSize, cpuHandle, gpuHandle));
}
return(new DescriptorHandle(_currentHeap, _descriptorSize, cpuHandle));
}
public void GetTempHandle(out CpuDescriptorHandle cpuHandle, out GpuDescriptorHandle gpuHandle)
{
CpuDescriptorHandle cpuHandle1 = heap.GetCPUDescriptorHandleForHeapStart();
cpuHandle1.Ptr += (nuint)(allocatedCount * IncrementSize);
GpuDescriptorHandle gpuHandle1 = heap.GetGPUDescriptorHandleForHeapStart();
gpuHandle1.Ptr += (ulong)(allocatedCount * IncrementSize);
allocatedCount = (allocatedCount + 1) % descriptorCount;
cpuHandle = cpuHandle1;
gpuHandle = gpuHandle1;
}
public unsafe void CreateShaderTable()
{
/** The shader-table layout is as follows:
* Entry 0 - Ray-gen program
* Entry 1 - Miss program for the primary ray
* Entry 2 - Miss programm for the shadow ray
* Entry 3,4 - Hit program for triangle 0 (primary followed by shadow)
* Entry 5,6 - Hit program for the plane (primary followed by shadow)
* Entry 7,8 - Hit program for triangle 1 (primary followed by shadow)
* Entry 9,10 - Hit program for triangle 2 (primary followed by shadow)
* All entries in the shader-table must have the same size, so we will choose it base on the largest required entry.
* The ray-gen program requires the largest entry - sizeof(program identifier) + 8 bytes for a descriptor-table.
* The entry size must be aligned up to D3D12_RAYTRACING_SHADER_RECORD_BYTE_ALIGNMENT
*/
// Calculate the size and create the buffer
mShaderTableEntrySize = D3D12ShaderIdentifierSizeInBytes;
mShaderTableEntrySize += 8; // the ray-gen's descriptor table
mShaderTableEntrySize = align_to(D3D12RaytracingShaderRecordByteAlignment, mShaderTableEntrySize);
uint shaderTableSize = mShaderTableEntrySize * 11;
// For simplicity, we create the shader.table on the upload heap. You can also create it on the default heap
mpShaderTable = this.acs.CreateBuffer(mpDevice, shaderTableSize, ResourceFlags.None, ResourceStates.GenericRead, AccelerationStructures.kUploadHeapProps);
// Map the buffer
IntPtr pData;
pData = mpShaderTable.Map(0, null);
ID3D12StateObjectProperties pRtsoProps;
pRtsoProps = mpPipelineState.QueryInterface <ID3D12StateObjectProperties>();
// Entry 0 - ray-gen program ID and descriptor data
Unsafe.CopyBlock((void *)pData, (void *)pRtsoProps.GetShaderIdentifier(RTPipeline.kRayGenShader), D3D12ShaderIdentifierSizeInBytes);
ulong heapStart = (ulong)mpSrvUavHeap.GetGPUDescriptorHandleForHeapStart().Ptr;
Unsafe.Write <ulong>((pData + (int)D3D12ShaderIdentifierSizeInBytes).ToPointer(), heapStart);
// Entry 1 - primary ray miss
pData += (int)mShaderTableEntrySize; // +1 skips ray-gen
Unsafe.CopyBlock((void *)pData, (void *)pRtsoProps.GetShaderIdentifier(RTPipeline.kMissShader), D3D12ShaderIdentifierSizeInBytes);
// Entry 2 - shadow-ray miss
pData += (int)mShaderTableEntrySize;
Unsafe.CopyBlock((void *)pData, (void *)pRtsoProps.GetShaderIdentifier(RTPipeline.kShadowMiss), D3D12ShaderIdentifierSizeInBytes);
// Entry 3 - Triangle 0, PRIMARY RAY. ProgramID and constant-buffer data
pData += (int)mShaderTableEntrySize;
Unsafe.CopyBlock((void *)pData, (void *)pRtsoProps.GetShaderIdentifier(RTPipeline.kTriHitGroup), D3D12ShaderIdentifierSizeInBytes);
void *pEntry3 = (pData + (int)D3D12ShaderIdentifierSizeInBytes).ToPointer();
Unsafe.Write <ulong>(pEntry3, (ulong)mpContantBuffer[0].GPUVirtualAddress);
// Entry 4 - Triangle 0, shadow ray. ProgramID only
pData += (int)mShaderTableEntrySize;
Unsafe.CopyBlock((void *)pData, (void *)pRtsoProps.GetShaderIdentifier(RTPipeline.kShadowHitGroup), D3D12ShaderIdentifierSizeInBytes);
// Entry 5 - Plane, primary ray. ProgramID only and the TLAS SRV
pData += (int)mShaderTableEntrySize;
Unsafe.CopyBlock((void *)pData, (void *)pRtsoProps.GetShaderIdentifier(RTPipeline.kPlaneHitGroup), D3D12ShaderIdentifierSizeInBytes);
void *pEntry5 = (pData + (int)D3D12ShaderIdentifierSizeInBytes).ToPointer();
Unsafe.Write <ulong>(pEntry5, heapStart + (ulong)mpDevice.GetDescriptorHandleIncrementSize(DescriptorHeapType.ConstantBufferViewShaderResourceViewUnorderedAccessView)); // The SRV comes directly after the program id
// Entry 6 - Plane shadow ray
pData += (int)mShaderTableEntrySize;
Unsafe.CopyBlock((void *)pData, (void *)pRtsoProps.GetShaderIdentifier(RTPipeline.kShadowHitGroup), D3D12ShaderIdentifierSizeInBytes);
// Entry 7 - Triangle 1 hit. ProgramID and constant-buffer data
pData += (int)mShaderTableEntrySize;
Unsafe.CopyBlock((void *)pData, (void *)pRtsoProps.GetShaderIdentifier(RTPipeline.kTriHitGroup), D3D12ShaderIdentifierSizeInBytes);
void *pEntry7 = (pData + (int)D3D12ShaderIdentifierSizeInBytes).ToPointer();
Unsafe.Write <ulong>(pEntry7, (ulong)mpContantBuffer[1].GPUVirtualAddress);
// Entry 8 - Triangle 1, shadow ray. ProgramID only
pData += (int)mShaderTableEntrySize;
Unsafe.CopyBlock((void *)pData, (void *)pRtsoProps.GetShaderIdentifier(RTPipeline.kShadowHitGroup), D3D12ShaderIdentifierSizeInBytes);
// Entry 9 - Triangle 2 hit. ProgramID and constant-buffer data
pData += (int)mShaderTableEntrySize;
Unsafe.CopyBlock((void *)pData, (void *)pRtsoProps.GetShaderIdentifier(RTPipeline.kTriHitGroup), D3D12ShaderIdentifierSizeInBytes);
void *pEntry9 = (pData + (int)D3D12ShaderIdentifierSizeInBytes).ToPointer();
Unsafe.Write <ulong>(pEntry9, (ulong)mpContantBuffer[2].GPUVirtualAddress);
// Entry 10 - Triangle 2, shadow ray. ProgramID only
pData += (int)mShaderTableEntrySize;
Unsafe.CopyBlock((void *)pData, (void *)pRtsoProps.GetShaderIdentifier(RTPipeline.kShadowHitGroup), D3D12ShaderIdentifierSizeInBytes);
// Unmap
mpShaderTable.Unmap(0, null);
}