#include "pch.h"
#include "CubeRenderer.h"

using namespace DirectX;
using namespace Microsoft::WRL;
using namespace Windows::Foundation;
using namespace Windows::UI::Core;

CubeRenderer::CubeRenderer() :
  m_loadingComplete(false),
  m_indexCount(0)
{
}

void CubeRenderer::CreateDeviceResources()
{
  Direct3DBase::CreateDeviceResources();

  auto loadVSTask = DX::ReadDataAsync("SimpleVertexShader.cso");
  auto loadPSTask = DX::ReadDataAsync("SimplePixelShader.cso");

  auto createVSTask = loadVSTask.then([this](Platform::Array<byte>^ fileData) {
    DX::ThrowIfFailed(
      m_d3dDevice->CreateVertexShader(
        fileData->Data,
        fileData->Length,
        nullptr,
        &m_vertexShader
        )
      );

    const D3D11_INPUT_ELEMENT_DESC vertexDesc[] =
    {
      { "POSITION", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0,  D3D11_INPUT_PER_VERTEX_DATA, 0 },
      { "COLOR",    0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 12, D3D11_INPUT_PER_VERTEX_DATA, 0 },
    };

    DX::ThrowIfFailed(
      m_d3dDevice->CreateInputLayout(
        vertexDesc,
        ARRAYSIZE(vertexDesc),
        fileData->Data,
        fileData->Length,
        &m_inputLayout
        )
      );
  });

  auto createPSTask = loadPSTask.then([this](Platform::Array<byte>^ fileData) {
    DX::ThrowIfFailed(
      m_d3dDevice->CreatePixelShader(
        fileData->Data,
        fileData->Length,
        nullptr,
        &m_pixelShader
        )
      );

    CD3D11_BUFFER_DESC constantBufferDesc(sizeof(ModelViewProjectionConstantBuffer), D3D11_BIND_CONSTANT_BUFFER);
    DX::ThrowIfFailed(
      m_d3dDevice->CreateBuffer(
        &constantBufferDesc,
        nullptr,
        &m_constantBuffer
        )
      );
  });

  auto createCubeTask = (createPSTask && createVSTask).then([this] () {
    VertexPositionColor cubeVertices[] =
    {
      {XMFLOAT3(-0.5f, -0.5f, -0.5f), XMFLOAT3(0.0f, 0.0f, 0.0f)},
      {XMFLOAT3(-0.5f, -0.5f,  0.5f), XMFLOAT3(0.0f, 0.0f, 1.0f)},
      {XMFLOAT3(-0.5f,  0.5f, -0.5f), XMFLOAT3(0.0f, 1.0f, 0.0f)},
      {XMFLOAT3(-0.5f,  0.5f,  0.5f), XMFLOAT3(0.0f, 1.0f, 1.0f)},
      {XMFLOAT3( 0.5f, -0.5f, -0.5f), XMFLOAT3(1.0f, 0.0f, 0.0f)},
      {XMFLOAT3( 0.5f, -0.5f,  0.5f), XMFLOAT3(1.0f, 0.0f, 1.0f)},
      {XMFLOAT3( 0.5f,  0.5f, -0.5f), XMFLOAT3(1.0f, 1.0f, 0.0f)},
      {XMFLOAT3( 0.5f,  0.5f,  0.5f), XMFLOAT3(1.0f, 1.0f, 1.0f)},
    };

    D3D11_SUBRESOURCE_DATA vertexBufferData = {0};
    vertexBufferData.pSysMem = cubeVertices;
    vertexBufferData.SysMemPitch = 0;
    vertexBufferData.SysMemSlicePitch = 0;
    CD3D11_BUFFER_DESC vertexBufferDesc(sizeof(cubeVertices), D3D11_BIND_VERTEX_BUFFER);
    DX::ThrowIfFailed(
      m_d3dDevice->CreateBuffer(
        &vertexBufferDesc,
        &vertexBufferData,
        &m_vertexBuffer
        )
      );

    unsigned short cubeIndices[] =
    {
      0,2,1, // -x
      1,2,3,

      4,5,6, // +x
      5,7,6,

      0,1,5, // -y
      0,5,4,

      2,6,7, // +y
      2,7,3,

      0,4,6, // -z
      0,6,2,

      1,3,7, // +z
      1,7,5,
    };

    m_indexCount = ARRAYSIZE(cubeIndices);

    D3D11_SUBRESOURCE_DATA indexBufferData = {0};
    indexBufferData.pSysMem = cubeIndices;
    indexBufferData.SysMemPitch = 0;
    indexBufferData.SysMemSlicePitch = 0;
    CD3D11_BUFFER_DESC indexBufferDesc(sizeof(cubeIndices), D3D11_BIND_INDEX_BUFFER);
    DX::ThrowIfFailed(
      m_d3dDevice->CreateBuffer(
        &indexBufferDesc,
        &indexBufferData,
        &m_indexBuffer
        )
      );
  });

  createCubeTask.then([this] () {
    m_loadingComplete = true;
  });
}

void CubeRenderer::CreateWindowSizeDependentResources()
{
  Direct3DBase::CreateWindowSizeDependentResources();

  float aspectRatio = m_windowBounds.Width / m_windowBounds.Height;
  float fovAngleY = 70.0f * XM_PI / 180.0f;
  if (aspectRatio < 1.0f)
  {
    fovAngleY /= aspectRatio;
  }

  // Note that the m_orientationTransform3D matrix is post-multiplied here
  // in order to correctly orient the scene to match the display orientation.
  // This post-multiplication step is required for any draw calls that are
  // made to the swap chain render target. For draw calls to other targets,
  // this transform should not be applied.
  XMStoreFloat4x4(
    &m_constantBufferData.projection,
    XMMatrixTranspose(
      XMMatrixMultiply(
        XMMatrixPerspectiveFovRH(
          fovAngleY,
          aspectRatio,
          0.01f,
          100.0f
          ),
        XMLoadFloat4x4(&m_orientationTransform3D)
        )
      )
    );
}

void CubeRenderer::Update(float timeTotal, float timeDelta)
{
  (void) timeDelta; // Unused parameter.

  XMVECTOR eye = XMVectorSet(0.0f, 0.7f, 1.5f, 0.0f);
  XMVECTOR at = XMVectorSet(0.0f, -0.1f, 0.0f, 0.0f);
  XMVECTOR up = XMVectorSet(0.0f, 1.0f, 0.0f, 0.0f);

  XMStoreFloat4x4(&m_constantBufferData.view, XMMatrixTranspose(XMMatrixLookAtRH(eye, at, up)));
  XMStoreFloat4x4(&m_constantBufferData.model, XMMatrixTranspose(XMMatrixRotationY(timeTotal * XM_PIDIV4)));
}

void CubeRenderer::Render()
{
  const float midnightBlue[] = { 0.098f, 0.098f, 0.439f, 1.000f };
  m_d3dContext->ClearRenderTargetView(
    m_renderTargetView.Get(),
    midnightBlue
    );

  m_d3dContext->ClearDepthStencilView(
    m_depthStencilView.Get(),
    D3D11_CLEAR_DEPTH,
    1.0f,
    0
    );

  // Only draw the cube once it is loaded (loading is asynchronous).
  if (!m_loadingComplete)
  {
    return;
  }

  m_d3dContext->OMSetRenderTargets(
    1,
    m_renderTargetView.GetAddressOf(),
    m_depthStencilView.Get()
    );

  m_d3dContext->UpdateSubresource(
    m_constantBuffer.Get(),
    0,
    NULL,
    &m_constantBufferData,
    0,
    0
    );

  UINT stride = sizeof(VertexPositionColor);
  UINT offset = 0;
  m_d3dContext->IASetVertexBuffers(
    0,
    1,
    m_vertexBuffer.GetAddressOf(),
    &stride,
    &offset
    );

  m_d3dContext->IASetIndexBuffer(
    m_indexBuffer.Get(),
    DXGI_FORMAT_R16_UINT,
    0
    );

  m_d3dContext->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST);

  m_d3dContext->IASetInputLayout(m_inputLayout.Get());

  m_d3dContext->VSSetShader(
    m_vertexShader.Get(),
    nullptr,
    0
    );

  m_d3dContext->VSSetConstantBuffers(
    0,
    1,
    m_constantBuffer.GetAddressOf()
    );

  m_d3dContext->PSSetShader(
    m_pixelShader.Get(),
    nullptr,
    0
    );

  m_d3dContext->DrawIndexed(
    m_indexCount,
    0,
    0
    );
}
