Small fixes to NRI Wrapper, Add external descriptor heap to D3D12 wrapper

[01Pollux]

No description provided.

[dzhdanNV]

Hi Yassine! Thanks. I have a question:
Why do you support old code path for textures:

    if (!textureDesc.textureDesc) {
        if (!GetTextureDesc(textureDesc, m_Desc))
            return Result::INVALID_ARGUMENT;
    } else {
        m_Desc = *textureDesc.textureDesc;
    }

but not for buffers:

    m_Desc = *bufferDesc.bufferDesc;

?
it can clearly hurt already written code...

[dzhdanNV]

I would suggest the following additions to your commit:

• return back bool nri::GetBufferDesc(const BufferD3D12Desc& bufferD3D12Desc, BufferDesc& bufferDesc) and fix it:
  • add forgotten ACCELERATION STRUCTURE bit
  • add VERTEX and INDEX bits unconditionally (AFAIR, these usages are always available in D3D)
• initialize buffer's m_Desc similarly to texture's m_Desc if the description is not provided (i.e. NULL)
• rename newly added bufferDesc and textureDesc to desc and add comment // (optional) if NULL, will be filled automatically but some info can be missing

[dzhdanNV]

I will do necessary changes myself. Thanks! Merged!