Input layout creation using reflection in DirectX 11

    // Load the shader as normal. Using the shader blob that was used to create the shader,
    // We can create a ID3D11ShaderReflection object that can be used to automatically build
    // the input layout.

    // Reflect the parameters from the shader.
    // Inspired by: http://members.gamedev.net/JasonZ/Heiroglyph/D3D11ShaderReflection.pdf
    Microsoft::WRL::ComPtr<ID3D11ShaderReflection> pReflector;
    hr = D3DReflect( m_pShaderBlob->GetBufferPointer(), m_pShaderBlob->GetBufferSize(), IID_ID3D11ShaderReflection, &pReflector );

    if ( FAILED( hr ) )
    {
        ReportError( "Failed to reflect shader." );
        return false;
    }

    // Query input parameters and build the input layout
    D3D11_SHADER_DESC shaderDescription;
    hr = pReflector->GetDesc( &shaderDescription );

    if ( FAILED( hr ) )
    {
        ReportError( "Failed to get shader description from shader reflector." );
        return false;
    }

    m_InputSemantics.clear();

    UINT numInputParameters = shaderDescription.InputParameters;
    std::vector<D3D11_INPUT_ELEMENT_DESC> inputElements;
    for ( UINT i = 0; i < numInputParameters; ++i )
    {
        D3D11_INPUT_ELEMENT_DESC inputElement;
        D3D11_SIGNATURE_PARAMETER_DESC parameterSignature;

        pReflector->GetInputParameterDesc( i, &parameterSignature );

        inputElement.SemanticName = parameterSignature.SemanticName;
        inputElement.SemanticIndex = parameterSignature.SemanticIndex;
        inputElement.InputSlot = i; // TODO: If using interleaved arrays, then the input slot should be 0.  If using packed arrays, the input slot will vary.
        inputElement.AlignedByteOffset = D3D11_APPEND_ALIGNED_ELEMENT;
        inputElement.InputSlotClass = D3D11_INPUT_PER_VERTEX_DATA; // TODO: Figure out how to deal with per-instance data? .. Don't. Just use structured buffers to store per-instance data and use the SV_InstanceID as an index in the structured buffer.
        inputElement.InstanceDataStepRate = 0;
        inputElement.Format = GetDXGIFormat( parameterSignature );

        assert( inputElement.Format != DXGI_FORMAT_UNKNOWN );

        inputElements.push_back( inputElement );

        m_InputSemantics.insert( SemanticMap::value_type( BufferBinding( inputElement.SemanticName, inputElement.SemanticIndex ), i ) );
    }

    if ( inputElements.size() > 0 )
    {
        hr = m_pDevice->CreateInputLayout( inputElements.data(), (UINT)inputElements.size(), m_pShaderBlob->GetBufferPointer(), m_pShaderBlob->GetBufferSize(), &m_pInputLayout );
        if ( FAILED( hr ) )
        {
            ReportError( "Failed to create input layout." );
            return false;
        }
    }