#include "pch.h"
#include "SampleFpsTextRenderer.h"

#include "Common/DirectXHelper.h"

using namespace $ext_safeprojectname$;
using namespace Microsoft::WRL;

// 初始化用于渲染文本的 D2D 资源。
SampleFpsTextRenderer::SampleFpsTextRenderer(const std::shared_ptr<DX::DeviceResources>& deviceResources) : 
	m_text(L""),
	m_deviceResources(deviceResources)
{
	ZeroMemory(&m_textMetrics, sizeof(DWRITE_TEXT_METRICS));

	// 创建独立于设备的资源
	ComPtr<IDWriteTextFormat> textFormat;
	DX::ThrowIfFailed(
		m_deviceResources->GetDWriteFactory()->CreateTextFormat(
			L"Segoe UI",
			nullptr,
			DWRITE_FONT_WEIGHT_LIGHT,
			DWRITE_FONT_STYLE_NORMAL,
			DWRITE_FONT_STRETCH_NORMAL,
			32.0f,
			L"en-US",
			&textFormat
			)
		);

	DX::ThrowIfFailed(
		textFormat.As(&m_textFormat)
		);

	DX::ThrowIfFailed(
		m_textFormat->SetParagraphAlignment(DWRITE_PARAGRAPH_ALIGNMENT_NEAR)
		);

	DX::ThrowIfFailed(
		m_deviceResources->GetD2DFactory()->CreateDrawingStateBlock(&m_stateBlock)
		);

	CreateDeviceDependentResources();
}

// 更新要显示的文本。
void SampleFpsTextRenderer::Update(DX::StepTimer const& timer)
{
	// 更新显示文本。
	uint32 fps = timer.GetFramesPerSecond();

	m_text = (fps > 0) ? std::to_wstring(fps) + L" FPS" : L" - FPS";

	ComPtr<IDWriteTextLayout> textLayout;
	DX::ThrowIfFailed(
		m_deviceResources->GetDWriteFactory()->CreateTextLayout(
			m_text.c_str(),
			(uint32) m_text.length(),
			m_textFormat.Get(),
			240.0f, // 输入文本的最大宽度。
			50.0f, // 输入文本的最大高度。
			&textLayout
			)
		);

	DX::ThrowIfFailed(
		textLayout.As(&m_textLayout)
		);

	DX::ThrowIfFailed(
		m_textLayout->GetMetrics(&m_textMetrics)
		);
}

// 将帧呈现到屏幕。
void SampleFpsTextRenderer::Render()
{
	ID2D1DeviceContext* context = m_deviceResources->GetD2DDeviceContext();
	Windows::Foundation::Size logicalSize = m_deviceResources->GetLogicalSize();

	context->SaveDrawingState(m_stateBlock.Get());
	context->BeginDraw();

	// 定位在右下角
	D2D1::Matrix3x2F screenTranslation = D2D1::Matrix3x2F::Translation(
		logicalSize.Width - m_textMetrics.layoutWidth,
		logicalSize.Height - m_textMetrics.height
		);

	context->SetTransform(screenTranslation * m_deviceResources->GetOrientationTransform2D());

	DX::ThrowIfFailed(
		m_textFormat->SetTextAlignment(DWRITE_TEXT_ALIGNMENT_TRAILING)
		);

	context->DrawTextLayout(
		D2D1::Point2F(0.f, 0.f),
		m_textLayout.Get(),
		m_whiteBrush.Get()
		);

	// 此处忽略 D2DERR_RECREATE_TARGET。此错误指示该设备
	// 丢失。将在下一次调用 Present 时对其进行处理。
	HRESULT hr = context->EndDraw();
	if (hr != D2DERR_RECREATE_TARGET)
	{
		DX::ThrowIfFailed(hr);
	}

	context->RestoreDrawingState(m_stateBlock.Get());
}

void SampleFpsTextRenderer::CreateDeviceDependentResources()
{
	DX::ThrowIfFailed(
		m_deviceResources->GetD2DDeviceContext()->CreateSolidColorBrush(D2D1::ColorF(D2D1::ColorF::White), &m_whiteBrush)
		);
}
void SampleFpsTextRenderer::ReleaseDeviceDependentResources()
{
	m_whiteBrush.Reset();
}