DirectXHelper.h

//*********************************************************
//
// Copyright (c) Microsoft. All rights reserved.
//
//*********************************************************

#pragma once

#include <ppltasks.h>

// Helper utilities for DirectX apps.
namespace DX
{
	inline void ThrowIfFailed(HRESULT hr)
	{
		if (FAILED(hr))
		{
			// Set a breakpoint on this line to catch DirectX API errors.
			throw Platform::Exception::CreateException(hr);
		}
	}

	// Converts between Color types.
    inline D2D1_COLOR_F ConvertToColorF(Windows::UI::Color color) 
    { 
        return D2D1::ColorF(color.R / 255.0f, color.G / 255.0f, color.B / 255.0f, color.A / 255.0f); 
    }
    
	// Converts between Point types.
    inline D2D1_POINT_2F ConvertToPoint2F(Windows::Foundation::Point point) 
    { 
        return D2D1::Point2F(point.X, point.Y);
    }

    // Converts a length in device-independent pixels (DIPs) to a length in physical pixels.
    inline float ConvertDipsToPixels(float dips)
    {
        static const float dipsPerInch = 96.0f;
        return floorf(dips * Windows::Graphics::Display::DisplayInformation::GetForCurrentView()->LogicalDpi / dipsPerInch + 0.5f); // Round to nearest integer.
    }

    // Converts a length in device-independent pixels (DIPs) to a length in physical pixels.
    inline Windows::Foundation::Point ConvertToScaledPoint(Windows::Foundation::Point point, float dpi)
    {
        static const float dipsPerInch = 96.0f;
        return Windows::Foundation::Point(point.X * dpi / dipsPerInch, point.Y * dpi / dipsPerInch);
    }

    // Function that reads from a binary file asynchronously.
    inline Concurrency::task<std::vector<byte>> ReadDataAsync(const std::wstring& filename)
    {
        using namespace Windows::Storage;
        using namespace Concurrency;

        auto folder = Windows::ApplicationModel::Package::Current->InstalledLocation;

        return create_task(folder->GetFileAsync(Platform::StringReference(filename.c_str()))).then([] (StorageFile^ file) 
        {
            return FileIO::ReadBufferAsync(file);
        }).then([] (Streams::IBuffer^ fileBuffer) -> std::vector<byte> 
        {
            std::vector<byte> returnBuffer;
            returnBuffer.resize(fileBuffer->Length);
            Streams::DataReader::FromBuffer(fileBuffer)->ReadBytes(Platform::ArrayReference<byte>(returnBuffer.data(), fileBuffer->Length));
            return returnBuffer;
        });
    }
}