Gist explaining Blending State and where to put what while coding

BlendStateGuide1.cpp

// Step 1 is to add:
// The alpha state to your Mesh Object.
// In my case I have a base MeshObject which is derived to all other objects
// -- MeshObject.h
ref class MeshObject
{
  //
  // Other code
  //
  
  Microsoft::WRL::ComPtr<ID3D11BlendState>	m_alphaBlendState;
  
  //
  // Other Code
  //
  virtual void Render(_In_ ID3D11DeviceContext *context); // You'll probably have something similar like this
}

// Step 2 is to Create a BlendingState and while creating this State we pass the `m_alphaBlendState` reference
// -- TileMesh.cpp : public MeshObject
TileMesh(_In_ ID3D11Device *device)
{
  // Constructor
  
  //
  // Other Code
  //
  
  D3D11_BLEND_DESC blendStateDescription;
	ZeroMemory(&blendStateDescription, sizeof(D3D11_BLEND_DESC));

  // [More Info](https://blogs.msdn.microsoft.com/rchiodo/2012/11/20/blending-demystified/)

  blendStateDescription.RenderTarget[0].BlendEnable = TRUE;
  blendStateDescription.RenderTarget[0].BlendOp = D3D11_BLEND_OP_ADD; // Set the Blend Mode to ADD which will elimate the black color
  blendStateDescription.RenderTarget[0].BlendOpAlpha = D3D11_BLEND_OP_ADD; // Same Here
  blendStateDescription.RenderTarget[0].DestBlend = D3D11_BLEND_INV_SRC_ALPHA; // Inverting the SRC Alpha
  blendStateDescription.RenderTarget[0].DestBlendAlpha = D3D11_BLEND_ZERO; // Blend 0 means 1.0 * 0.0 = 0.0 (OP_ADD)
  blendStateDescription.RenderTarget[0].RenderTargetWriteMask = 0x0f;
  blendStateDescription.RenderTarget[0].SrcBlend = D3D11_BLEND_ONE; // Blend 1 means 1.0 * 1.0 = 1.0 (OP_ADD)
  blendStateDescription.RenderTarget[0].SrcBlendAlpha = D3D11_BLEND_ONE; // Blend 0 means 1.0 * 1.0 = 1.0 (OP_ADD)
  AzuraException::ThrowIfFailed(
    device->CreateBlendState(&blendStateDescription, &m_alphaBlendState) // Notice the Reference from the Base class's Property
  );
}

// Step 3 is to attach this m_alphaBlendState to the Render Phase where we tell the Device to use this Alpha while rendering this mesh
// -- MeshObject.cpp
void Render(_In_ ID3D11DeviceContext *context)
{
  //
  // Other Code
  //
  
  // 1st Param is our Alpha State
  // 2nd Param is BlendFactors: we can set that to NULL as it didn't have an effect when I set it to other values
  // 3rd is Mask: We can use the default value
  // Ref: https://msdn.microsoft.com/en-us/library/windows/desktop/ff476462(v=vs.85).aspx
  context->OMSetBlendState(m_alphaBlendState.Get(), NULL, 0xffffffff);
  
  //
  // Other Code
  //
}