Drawing a transparent image with OpenGL ES in a UWP XAML app

In my previous post Testing XAML App for OpenGL ES on Windows 10 Mobile Device I described the changes I made to UWP application based on “XAML App for OpenGL ES (Universal Windows)” template to demonstrate some strange effect related to the transparency of the image drawn with OpenGL ES in SwapChainPanel. But I did yet another experiment with this application and got some beautiful pictures that demonstrate what happens if I make the scene completely transparent with the following code:

void SimpleRenderer::Draw()
{
    glEnable(GL_DEPTH_TEST);
    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    ...
}

(more…)

Testing XAML App for OpenGL ES on Windows 10 Mobile Device

Today I played a bit with a UWP application based on “XAML App for OpenGL ES (Universal Windows)” template and realized that there is some specific bug probably related to the interaction between SwapChainPanel and OpenGL surface. First, I made the cube transparent by changing two lines of code in the vertex shader:

const std::string vs = STRING
(
    uniform mat4 uModelMatrix;
    uniform mat4 uViewMatrix;
    uniform mat4 uProjMatrix;
    attribute vec4 aPosition;
    attribute vec3 aColor;
    varying vec4 vColor;
    void main()
    {
        gl_Position = uProjMatrix * uViewMatrix * uModelMatrix * aPosition;
        vColor = vec4(aColor, 0.1);
    }
);

(more…)

UWP Application beta testing

There are two main options in the Windows Store how to hide the app from public but make it available for specific users or beta testers: Package flights and Promotional codes. Below I briefly describe how I used Promotional codes with my app by the example of Lines 3D game.

According to the Microsoft guide, in my submission on the Pricing and availability page in Distribution and visibility I chosen Hide this app and prevent acquisition. Customers with a promotional code can still download it on Windows 10 devices. Then I generated one promotional code and got so called “Redeemable URL” or the app activation link in other words.

(more…)

How to compile QT 5.7 with VS2015

Below I provided a simple step by step instruction on how to compile QT 5.7 with VS2015 assuming you already have VS2015 and Git client installed on your Windows machine.

Install Perl, Python and Ruby.

To get QT 5.7 sources open Git Bash and run the following command (the repository has some submodules, so “recursive” option is required):

git clone --recursive https://github.com/qtproject/qt5.git --branch 5.7

Create a bat file called configureqt.bat with the following content:

set PATH=%PATH%;"C:\Program Files (x86)\Portable\ruby-2.3.0-i386-mingw32\bin";C:\Perl\bin;C:\Python27
D:
cd D:\Repos\qt5\
set _ROOT=D:\Repos\qt5
set PATH=%_ROOT%\qtbase\bin;%_ROOT%\gnuwin32\bin;%PATH%
set QMAKESPEC=win32-msvc2015
set _ROOT=
configure -debug -nomake examples -opensource

(more…)

Using OpenGL 3.0 with MSOpenTech ANGLE

Typically ANGLE library is used with OpenGL 2.0, but I successfully tried to enable OpenGL 3.0:

const EGLint contextAttributes[] = 
{ 
    EGL_CONTEXT_CLIENT_VERSION, 3, 
    EGL_NONE
};

and used some OpenGL 3.0 features in my Universal Windows App. But today I tried to compile my application with the new version of ANGLE library and got EGL_BAD_CONFIG error while creating the OpenGL context. The source code that returns this error checks some EGL_OPENGL_ES3_BIT_KHR that is not set in the new version:

if (clientMajorVersion == 3 && !(configuration->conformant & EGL_OPENGL_ES3_BIT_KHR))
{
    return Error(EGL_BAD_CONFIG);
}

(more…)

Debugging a C++ application on an Android device with VS2015 on Windows 10

VS2015 has an exciting ability to debug a C++ application on Android Emulator, but in this article I will talk about no less exciting and more time expensive ability to debug a C++ application on a real Android device. The first thing we need to spend the time with is figuring out how to enable USB debugging mode on our Android device. On my ASUS Zenfone I need to go to Settings->About->Software Information and tap on Build Number 7 times, after that I have USB debugging check box in Settings->Developer Options that I should tap as well:

enabling USB debugging mode on Android device USB debugging mode on Android device

(more…)

How to uninstall Microsoft Advertising SDK for Windows 8.1

Windows 10 Advertising SDK Walkthrough article states that “it is highly recommended that you uninstall all prior instances of the Advertising SDK”. I am not sure that the article is relevant, because it mentions some preview version of SDK, but never too much of a good thing, so I decided to get rid of Advertising SDK for Windows 8.1 that is listed in VS2015 extensions along with the new SDK:

Microsoft Advertising SDK for Windows 8.1

(more…)

Listening to a dependency property changes in Universal Windows App in C++

If you want to be notified when some dependency property of a control changes, for example, UIElement::Visibility, you can do the following trick. First declare you own dependency property of the same type in some class:

public ref class MyListener
{
public:

    static property Windows::UI::Xaml::DependencyProperty ^ BoundVisibilityProperty
    {
        Windows::UI::Xaml::DependencyProperty ^ get() { return boundVisibilityProperty; }
    }

    property Windows::UI::Xaml::Visibility BoundVisibility
    {
        Windows::UI::Xaml::Visibility get() { return safe_cast<Windows::UI::Xaml::Visibility>(GetValue(boundVisibilityProperty)); }
        void set(Windows::UI::Xaml::Visibility value) { SetValue(boundVisibilityProperty, value); }
    }

    static Windows::UI::Xaml::DependencyProperty ^ boundVisibilityProperty;

    static void OnBoundVisibilityChanged(DependencyObject^ d, Windows::UI::Xaml::DependencyPropertyChangedEventArgs^ e);
};

(more…)

Drawing 2D vector Nautical Charts with OpenGL ES 2.0/3.2

In this article, I will show how the basic OpenGL ES 2.0/3.2 techniques, allowing to utilize the power of modern GPUs, can be used to draw 2D vector nautical charts by the example of S57 format. And as you probably already have guessed, the first technique I am going to consider is using vertex buffers for storing objects that makes up the chart. I will say at once that it is not a trivial task because, for example, some area in S57 chart can be filled and outlined with specific patterns generated from so called Presentation Library and at that, the fill pattern should be aligned to the left-top corner of the screen, but not to the area itself, so when the user shift the chart, the fill pattern does not move. The other example is a point objects or symbol that should be shown in the center of the visible part of an area, so its geographical coordinates changes when the user offsets or scales the chart. Theoretically, if we have OpenGL ES 3.2, we can use geometry shaders for drawing patterns, but if we have only OpenGL ES 2.0 that does not support geometry shaders, those patterns can also be drawn with the vertex buffers that should be regenerated each time the user changes the scale. So let’s start to solve this complex task with a simple example when we have geographic area or polygon filled with blue color, at least this example will demonstrate the basic idea of using the vertex buffers.

(more…)

Developing Universal Windows App (UWP) with Xamarin.Forms 2.0 in Visual Studio 2015

Visual Studio 2015 has “Blank App (Xamarin.Forms Portable)” project template that creates three separate C# projects for Android, iOS and Windows.Phone 8.0 platforms that share the same C#/XAML code via so called PCL (Portable Class Library):

Blank App (Xamarin.Forms Portable)

(more…)