SDL/src/video/windowsrt/SDL_winrtrenderer.cpp

#include "SDLmain_WinRT_common.h"
#include "SDL_winrtrenderer.h"

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

// Constructor.
SDL_winrtrenderer::SDL_winrtrenderer() :
    m_loadingComplete(false),
	m_vertexCount(0)
{
}

// Initialize the Direct3D resources required to run.
void SDL_winrtrenderer::Initialize(CoreWindow^ window)
{
	m_window = window;
	
	CreateDeviceResources();
	CreateWindowSizeDependentResources();
}

// Recreate all device resources and set them back to the current state.
void SDL_winrtrenderer::HandleDeviceLost()
{
	// Reset these member variables to ensure that UpdateForWindowSizeChange recreates all resources.
	m_windowBounds.Width = 0;
	m_windowBounds.Height = 0;
	m_swapChain = nullptr;

	CreateDeviceResources();
	UpdateForWindowSizeChange();
}

// These are the resources that depend on the device.
void SDL_winrtrenderer::CreateDeviceResources()
{
	// This flag adds support for surfaces with a different color channel ordering
	// than the API default. It is required for compatibility with Direct2D.
	UINT creationFlags = D3D11_CREATE_DEVICE_BGRA_SUPPORT;

#if defined(_DEBUG)
	// If the project is in a debug build, enable debugging via SDK Layers with this flag.
	creationFlags |= D3D11_CREATE_DEVICE_DEBUG;
#endif

	// This array defines the set of DirectX hardware feature levels this app will support.
	// Note the ordering should be preserved.
	// Don't forget to declare your application's minimum required feature level in its
	// description.  All applications are assumed to support 9.1 unless otherwise stated.
	D3D_FEATURE_LEVEL featureLevels[] = 
	{
		D3D_FEATURE_LEVEL_11_1,
		D3D_FEATURE_LEVEL_11_0,
		D3D_FEATURE_LEVEL_10_1,
		D3D_FEATURE_LEVEL_10_0,
		D3D_FEATURE_LEVEL_9_3,
		D3D_FEATURE_LEVEL_9_2,
		D3D_FEATURE_LEVEL_9_1
	};

	// Create the Direct3D 11 API device object and a corresponding context.
	ComPtr<ID3D11Device> device;
	ComPtr<ID3D11DeviceContext> context;
	DX::ThrowIfFailed(
		D3D11CreateDevice(
			nullptr, // Specify nullptr to use the default adapter.
			D3D_DRIVER_TYPE_HARDWARE,
			nullptr,
			creationFlags, // Set set debug and Direct2D compatibility flags.
			featureLevels, // List of feature levels this app can support.
			ARRAYSIZE(featureLevels),
			D3D11_SDK_VERSION, // Always set this to D3D11_SDK_VERSION for Windows Store apps.
			&device, // Returns the Direct3D device created.
			&m_featureLevel, // Returns feature level of device created.
			&context // Returns the device immediate context.
			)
		);

	// Get the Direct3D 11.1 API device and context interfaces.
	DX::ThrowIfFailed(
		device.As(&m_d3dDevice)
		);

	DX::ThrowIfFailed(
		context.As(&m_d3dContext)
		);

    auto loadVSTask = DX::ReadDataAsync("SDL_VS2012_WinRT\\SimpleVertexShader.cso");
	auto loadPSTask = DX::ReadDataAsync("SDL_VS2012_WinRT\\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 },
			{ "TEXCOORD", 0, DXGI_FORMAT_R32G32_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
				)
			);
	});

	auto createVertexBuffer = (createPSTask && createVSTask).then([this] () {
		VertexPositionColor vertices[] = 
		{
			{XMFLOAT3(-1.0f, -1.0f, 0.0f),  XMFLOAT2(0.0f, 1.0f)},
			{XMFLOAT3(-1.0f, 1.0f, 0.0f), XMFLOAT2(0.0f, 0.0f)},
			{XMFLOAT3(1.0f, -1.0f, 0.0f), XMFLOAT2(1.0f, 1.0f)},
			{XMFLOAT3(1.0f, 1.0f, 0.0f), XMFLOAT2(1.0f, 0.0f)},
		};

		m_vertexCount = ARRAYSIZE(vertices);

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

    auto createMainSamplerTask = createVertexBuffer.then([this] () {
		D3D11_SAMPLER_DESC samplerDesc;
		samplerDesc.Filter = D3D11_FILTER_MIN_MAG_MIP_POINT;
		samplerDesc.AddressU = D3D11_TEXTURE_ADDRESS_CLAMP;
		samplerDesc.AddressV = D3D11_TEXTURE_ADDRESS_CLAMP;
		samplerDesc.AddressW = D3D11_TEXTURE_ADDRESS_CLAMP;
		samplerDesc.MipLODBias = 0.0f;
		samplerDesc.MaxAnisotropy = 1;
		samplerDesc.ComparisonFunc = D3D11_COMPARISON_ALWAYS;
		samplerDesc.BorderColor[0] = 0.0f;
		samplerDesc.BorderColor[1] = 0.0f;
		samplerDesc.BorderColor[2] = 0.0f;
		samplerDesc.BorderColor[3] = 0.0f;
		samplerDesc.MinLOD = 0.0f;
		samplerDesc.MaxLOD = D3D11_FLOAT32_MAX;
		DX::ThrowIfFailed(
			m_d3dDevice->CreateSamplerState(
				&samplerDesc,
				&m_mainSampler
				)
			);
	});

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

// Allocate all memory resources that change on a window SizeChanged event.
void SDL_winrtrenderer::CreateWindowSizeDependentResources()
{ 
	// Store the window bounds so the next time we get a SizeChanged event we can
	// avoid rebuilding everything if the size is identical.
	m_windowBounds = m_window->Bounds;

	// Calculate the necessary swap chain and render target size in pixels.
	float windowWidth = ConvertDipsToPixels(m_windowBounds.Width);
	float windowHeight = ConvertDipsToPixels(m_windowBounds.Height);

	// The width and height of the swap chain must be based on the window's
	// landscape-oriented width and height. If the window is in a portrait
	// orientation, the dimensions must be reversed.
	m_orientation = DisplayProperties::CurrentOrientation;
	bool swapDimensions =
		m_orientation == DisplayOrientations::Portrait ||
		m_orientation == DisplayOrientations::PortraitFlipped;
	m_renderTargetSize.Width = swapDimensions ? windowHeight : windowWidth;
	m_renderTargetSize.Height = swapDimensions ? windowWidth : windowHeight;

	if(m_swapChain != nullptr)
	{
		// If the swap chain already exists, resize it.
		DX::ThrowIfFailed(
			m_swapChain->ResizeBuffers(
				2, // Double-buffered swap chain.
				static_cast<UINT>(m_renderTargetSize.Width),
				static_cast<UINT>(m_renderTargetSize.Height),
				DXGI_FORMAT_B8G8R8A8_UNORM,
				0
				)
			);
	}
	else
	{
		// Otherwise, create a new one using the same adapter as the existing Direct3D device.
		DXGI_SWAP_CHAIN_DESC1 swapChainDesc = {0};
		swapChainDesc.Width = static_cast<UINT>(m_renderTargetSize.Width); // Match the size of the window.
		swapChainDesc.Height = static_cast<UINT>(m_renderTargetSize.Height);
		swapChainDesc.Format = DXGI_FORMAT_B8G8R8A8_UNORM; // This is the most common swap chain format.
		swapChainDesc.Stereo = false;
		swapChainDesc.SampleDesc.Count = 1; // Don't use multi-sampling.
		swapChainDesc.SampleDesc.Quality = 0;
		swapChainDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
		swapChainDesc.BufferCount = 2; // Use double-buffering to minimize latency.
		swapChainDesc.Scaling = DXGI_SCALING_NONE;
		swapChainDesc.SwapEffect = DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL; // All Windows Store apps must use this SwapEffect.
		swapChainDesc.Flags = 0;

		ComPtr<IDXGIDevice1>  dxgiDevice;
		DX::ThrowIfFailed(
			m_d3dDevice.As(&dxgiDevice)
			);

		ComPtr<IDXGIAdapter> dxgiAdapter;
		DX::ThrowIfFailed(
			dxgiDevice->GetAdapter(&dxgiAdapter)
			);

		ComPtr<IDXGIFactory2> dxgiFactory;
		DX::ThrowIfFailed(
			dxgiAdapter->GetParent(
				__uuidof(IDXGIFactory2), 
				&dxgiFactory
				)
			);

		Windows::UI::Core::CoreWindow^ window = m_window.Get();
		DX::ThrowIfFailed(
			dxgiFactory->CreateSwapChainForCoreWindow(
				m_d3dDevice.Get(),
				reinterpret_cast<IUnknown*>(window),
				&swapChainDesc,
				nullptr, // Allow on all displays.
				&m_swapChain
				)
			);
			
		// Ensure that DXGI does not queue more than one frame at a time. This both reduces latency and
		// ensures that the application will only render after each VSync, minimizing power consumption.
		DX::ThrowIfFailed(
			dxgiDevice->SetMaximumFrameLatency(1)
			);
	}
	
	// Set the proper orientation for the swap chain, and generate the
	// 3D matrix transformation for rendering to the rotated swap chain.
	DXGI_MODE_ROTATION rotation = DXGI_MODE_ROTATION_UNSPECIFIED;
	switch (m_orientation)
	{
		case DisplayOrientations::Landscape:
			rotation = DXGI_MODE_ROTATION_IDENTITY;
			m_orientationTransform3D = XMFLOAT4X4( // 0-degree Z-rotation
				1.0f, 0.0f, 0.0f, 0.0f,
				0.0f, 1.0f, 0.0f, 0.0f,
				0.0f, 0.0f, 1.0f, 0.0f,
				0.0f, 0.0f, 0.0f, 1.0f
				);
			break;

		case DisplayOrientations::Portrait:
			rotation = DXGI_MODE_ROTATION_ROTATE270;
			m_orientationTransform3D = XMFLOAT4X4( // 90-degree Z-rotation
				0.0f, 1.0f, 0.0f, 0.0f,
				-1.0f, 0.0f, 0.0f, 0.0f,
				0.0f, 0.0f, 1.0f, 0.0f,
				0.0f, 0.0f, 0.0f, 1.0f
				);
			break;

		case DisplayOrientations::LandscapeFlipped:
			rotation = DXGI_MODE_ROTATION_ROTATE180;
			m_orientationTransform3D = XMFLOAT4X4( // 180-degree Z-rotation
				-1.0f, 0.0f, 0.0f, 0.0f,
				0.0f, -1.0f, 0.0f, 0.0f,
				0.0f, 0.0f, 1.0f, 0.0f,
				0.0f, 0.0f, 0.0f, 1.0f
				);
			break;

		case DisplayOrientations::PortraitFlipped:
			rotation = DXGI_MODE_ROTATION_ROTATE90;
			m_orientationTransform3D = XMFLOAT4X4( // 270-degree Z-rotation
				0.0f, -1.0f, 0.0f, 0.0f,
				1.0f, 0.0f, 0.0f, 0.0f,
				0.0f, 0.0f, 1.0f, 0.0f,
				0.0f, 0.0f, 0.0f, 1.0f
				);
			break;

		default:
			throw ref new Platform::FailureException();
	}

	DX::ThrowIfFailed(
		m_swapChain->SetRotation(rotation)
		);

	// Create a render target view of the swap chain back buffer.
	ComPtr<ID3D11Texture2D> backBuffer;
	DX::ThrowIfFailed(
		m_swapChain->GetBuffer(
			0,
			__uuidof(ID3D11Texture2D),
			&backBuffer
			)
		);

	DX::ThrowIfFailed(
		m_d3dDevice->CreateRenderTargetView(
			backBuffer.Get(),
			nullptr,
			&m_renderTargetView
			)
		);

	// Create a depth stencil view.
	CD3D11_TEXTURE2D_DESC depthStencilDesc(
		DXGI_FORMAT_D24_UNORM_S8_UINT, 
		static_cast<UINT>(m_renderTargetSize.Width),
		static_cast<UINT>(m_renderTargetSize.Height),
		1,
		1,
		D3D11_BIND_DEPTH_STENCIL
		);

	ComPtr<ID3D11Texture2D> depthStencil;
	DX::ThrowIfFailed(
		m_d3dDevice->CreateTexture2D(
			&depthStencilDesc,
			nullptr,
			&depthStencil
			)
		);

	// Set the rendering viewport to target the entire window.
	CD3D11_VIEWPORT viewport(
		0.0f,
		0.0f,
		m_renderTargetSize.Width,
		m_renderTargetSize.Height
		);

	m_d3dContext->RSSetViewports(1, &viewport);
}

void SDL_winrtrenderer::ResizeMainTexture(int w, int h)
{
    D3D11_TEXTURE2D_DESC textureDesc = {0};
	textureDesc.Width = w;
	textureDesc.Height = h;
	textureDesc.MipLevels = 1;
	textureDesc.ArraySize = 1;
	textureDesc.Format = DXGI_FORMAT_B8G8R8A8_UNORM;
	textureDesc.SampleDesc.Count = 1;
	textureDesc.SampleDesc.Quality = 0;
	textureDesc.Usage = D3D11_USAGE_DYNAMIC;
	textureDesc.BindFlags = D3D11_BIND_SHADER_RESOURCE;
	textureDesc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;
	textureDesc.MiscFlags = 0;

	const int numPixels = textureDesc.Width * textureDesc.Height;
	std::vector<uint8> initialTexturePixels(numPixels * 4, 0x00);
	D3D11_SUBRESOURCE_DATA initialTextureData = {0};
	initialTextureData.pSysMem = (void *)&(initialTexturePixels[0]);
	initialTextureData.SysMemPitch = textureDesc.Width * 4;
	initialTextureData.SysMemSlicePitch = numPixels * 4;
	DX::ThrowIfFailed(
		m_d3dDevice->CreateTexture2D(
			&textureDesc,
			&initialTextureData,
			&m_mainTexture
			)
		);

	D3D11_SHADER_RESOURCE_VIEW_DESC resourceViewDesc;
	resourceViewDesc.Format = textureDesc.Format;
	resourceViewDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE2D;
	resourceViewDesc.Texture2D.MostDetailedMip = 0;
	resourceViewDesc.Texture2D.MipLevels = textureDesc.MipLevels;
	DX::ThrowIfFailed(
		m_d3dDevice->CreateShaderResourceView(
			m_mainTexture.Get(),
			&resourceViewDesc,
			&m_mainTextureResourceView)
		);
}

// This method is called in the event handler for the SizeChanged event.
void SDL_winrtrenderer::UpdateForWindowSizeChange()
{
	if (m_window->Bounds.Width  != m_windowBounds.Width ||
		m_window->Bounds.Height != m_windowBounds.Height ||
		m_orientation != DisplayProperties::CurrentOrientation)
	{
		ID3D11RenderTargetView* nullViews[] = {nullptr};
		m_d3dContext->OMSetRenderTargets(ARRAYSIZE(nullViews), nullViews, nullptr);
		m_renderTargetView = nullptr;
		m_d3dContext->Flush();
		CreateWindowSizeDependentResources();
	}
}

void SDL_winrtrenderer::Render(SDL_Surface * surface, SDL_Rect * rects, int numrects)
{
	const float blackColor[] = { 0.0f, 0.0f, 0.0f, 1.0f };
	m_d3dContext->ClearRenderTargetView(
		m_renderTargetView.Get(),
		blackColor
		);

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

	// Update the main texture (for SDL usage):
	D3D11_MAPPED_SUBRESOURCE textureMemory = {0};
	DX::ThrowIfFailed(
		m_d3dContext->Map(
			m_mainTexture.Get(),
			0,
			D3D11_MAP_WRITE_DISCARD,
			0,
			&textureMemory)
		);

	// TODO, WinRT: only copy over the requested rects (via SDL_BlitSurface, perhaps?)
	// TODO, WinRT: do a sanity check on the src and dest data when updating the window surface
    D3D11_TEXTURE2D_DESC textureDesc = {0};
    m_mainTexture->GetDesc(&textureDesc);
	const unsigned int numBytes = textureDesc.Width * textureDesc.Height * 4;
	memcpy(textureMemory.pData, surface->pixels, numBytes);

	m_d3dContext->Unmap(
		m_mainTexture.Get(),
		0);

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

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

	m_d3dContext->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLESTRIP);

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

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

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

	m_d3dContext->PSSetShaderResources(0, 1, m_mainTextureResourceView.GetAddressOf());

	m_d3dContext->PSSetSamplers(0, 1, m_mainSampler.GetAddressOf());

	m_d3dContext->Draw(4, 0);
}

// Method to deliver the final image to the display.
void SDL_winrtrenderer::Present()
{
	// The application may optionally specify "dirty" or "scroll"
	// rects to improve efficiency in certain scenarios.
	DXGI_PRESENT_PARAMETERS parameters = {0};
	parameters.DirtyRectsCount = 0;
	parameters.pDirtyRects = nullptr;
	parameters.pScrollRect = nullptr;
	parameters.pScrollOffset = nullptr;
	
	// The first argument instructs DXGI to block until VSync, putting the application
	// to sleep until the next VSync. This ensures we don't waste any cycles rendering
	// frames that will never be displayed to the screen.
	HRESULT hr = m_swapChain->Present1(1, 0, &parameters);

	// Discard the contents of the render target.
	// This is a valid operation only when the existing contents will be entirely
	// overwritten. If dirty or scroll rects are used, this call should be removed.
	m_d3dContext->DiscardView(m_renderTargetView.Get());

	// If the device was removed either by a disconnect or a driver upgrade, we 
	// must recreate all device resources.
	if (hr == DXGI_ERROR_DEVICE_REMOVED)
	{
		HandleDeviceLost();
	}
	else
	{
		DX::ThrowIfFailed(hr);
	}
}

// Method to convert a length in device-independent pixels (DIPs) to a length in physical pixels.
float SDL_winrtrenderer::ConvertDipsToPixels(float dips)
{
	static const float dipsPerInch = 96.0f;
	return floor(dips * DisplayProperties::LogicalDpi / dipsPerInch + 0.5f); // Round to nearest integer.
}