DirectX 11 Shader Reflection: Need help setting Constant Buffers variables by name - c++

Question

I'm creating a system that allows the manipulation of constant buffer variables by name using their byte offsets and byte sizes via Shader Reflection. I can bind the buffers to the Device Context just fine, but none of the cubes in my 3D scene are showing up. I believe this is because something is wrong with how I'm mapping data to the Constant Buffers. I cast the struct, be it a float4 or a matrix to a void pointer, and then copy that void pointer data to a another structure that has the variable's name. Once the shader needs to have its buffers updated before a draw call, I map the data of every structure in the list during the Map/Unmap call with a pointer iterator. Also, there seems to be a crash whenever the program calls the destructor on one of the shader constant structures. Below is the code i've written so far:
I'm mapping the buffer data through this algorithm here:
void DynamicConstantBuffer::UpdateChanges(ID3D11DeviceContext* pDeviceContext)
{
D3D11_MAPPED_SUBRESOURCE mappedResource;
HRESULT hr = pDeviceContext->Map(m_Buffer.Get(), 0, D3D11_MAP_WRITE_DISCARD, 0, &mappedResource);
if (FAILED(hr)) return;
// Set mapped data
for (const auto& constant : m_BufferConstants)
{
char* startPosition = static_cast<char*>(mappedResource.pData) + constant.desc.StartOffset;
memcpy(startPosition, constant.pData, sizeof(constant.pData));
}
// Copy memory and unmap
pDeviceContext->Unmap(m_Buffer.Get(), 0);
}
I'm initializing the Constant Buffer here:
BOOL DynamicConstantBuffer::Initialize(UINT nBufferSlot, ID3D11Device* pDevice, ID3D11ShaderReflection* pShaderReflection)
{
ID3D11ShaderReflectionConstantBuffer* pReflectionBuffer = NULL;
D3D11_SHADER_BUFFER_DESC cbShaderDesc = {};
// Fetch constant buffer description
if (!(pReflectionBuffer = pShaderReflection->GetConstantBufferByIndex(nBufferSlot)))
return FALSE;
// Get description
pReflectionBuffer->GetDesc(&cbShaderDesc);
m_BufferSize = cbShaderDesc.Size;
// Create constant buffer on gpu end
D3D11_BUFFER_DESC cbDescription = {};
cbDescription.Usage = D3D11_USAGE_DYNAMIC;
cbDescription.BindFlags = D3D11_BIND_CONSTANT_BUFFER;
cbDescription.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;
cbDescription.ByteWidth = cbShaderDesc.Size;
if (FAILED(pDevice->CreateBuffer(&cbDescription, NULL, m_Buffer.GetAddressOf())))
return FALSE;
// Poll shader variables
for (UINT i = 0; i < cbShaderDesc.Variables; i++)
{
ID3D11ShaderReflectionVariable* pVariable = NULL;
pVariable = pReflectionBuffer->GetVariableByIndex(i);
// Get variable description
D3D11_SHADER_VARIABLE_DESC variableDesc = {};
pVariable->GetDesc(&variableDesc);
// Push variable back into list of variables
m_BufferConstants.push_back(ShaderConstant(variableDesc));
}
return TRUE;}
Here's the method that sets a variable within the constant buffer:
BOOL DynamicConstantBuffer::SetConstantVariable(const std::string& varName, const void* varData)
{
for (auto& v : m_BufferConstants)
{
if (v.desc.Name == varName)
{
memcpy(v.pData, varData, sizeof(varData));
bBufferDirty = TRUE;
return TRUE;
}
}
// No variable to assign :(
return FALSE;
}
Here's the class layout for ShaderConstant:
class ShaderConstant
{
public:
ShaderConstant(D3D11_SHADER_VARIABLE_DESC& desc)
{
this->desc = desc;
pData = new char[desc.Size];
_size = desc.Size;
};
~ShaderConstant()
{
if (!pData)
return;
delete[] pData;
pData = NULL;
}
D3D11_SHADER_VARIABLE_DESC desc;
void* pData;
size_t _size;
};
Any help at all would be appreciated. Thank you.