#include "SDLmain_WinRT_common.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;

	// 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
		);
}