Friday, November 14, 2014

Native Android Application Development with C++ and Visual Studio 2015

Visual Studio 2015 ships the new C++ cross platform support which currently provides native C++ library compilation for Android and Windows platforms. iOS compiler support is supposed to be added as well.
That's not all. VS 2015 even provides a new project type called "Native-Activity Application" for Android app development. This pure C/C++ Android application model is mainly used for game development using full screen OpenGL rendering.
The Native-Activity Application project type allows developers to write native Android apps with C++ and even to run and debug those in the Android emulator only by using Visual Studio 2015.
No Xamarin, no Apache Cordova needed, just VS 2015 and pure C/C++.

How it works

It's pretty straightforward to get started.
Just install Visual Studio 2015 including its Secondary installer which adds the required Android development tools.
Start VS 2015 and select the Visual C++ -> Cross Platform -> Native-Activity Application (Android) project type:

The generated template code provides the base native Android app code including simple code for cycling the back buffer clear color inside the engine_draw_frame function.

For this sample here I decided to make the Hello World of 3D computer graphics: a rainbow colored rotating cube. Here's how you can achieve this as well:

Add the cube definitions to the beginning of the main.cpp:

static GLint vertices[][3] =
 { -0x10000, -0x10000, -0x10000 },
 { 0x10000, -0x10000, -0x10000 },
 { 0x10000,  0x10000, -0x10000 },
 { -0x10000,  0x10000, -0x10000 },
 { -0x10000, -0x10000,  0x10000 },
 { 0x10000, -0x10000,  0x10000 },
 { 0x10000,  0x10000,  0x10000 },
 { -0x10000,  0x10000,  0x10000 }

static GLint colors[][4] =
 { 0x00000, 0x00000, 0x00000, 0x10000 },
 { 0x10000, 0x00000, 0x00000, 0x10000 },
 { 0x10000, 0x10000, 0x00000, 0x10000 },
 { 0x00000, 0x10000, 0x00000, 0x10000 },
 { 0x00000, 0x00000, 0x10000, 0x10000 },
 { 0x10000, 0x00000, 0x10000, 0x10000 },
 { 0x10000, 0x10000, 0x10000, 0x10000 },
 { 0x00000, 0x10000, 0x10000, 0x10000 }

GLubyte indices[] = {
 0, 4, 5,    0, 5, 1,
 1, 5, 6,    1, 6, 2,
 2, 6, 7,    2, 7, 3,
 3, 7, 4,    3, 4, 0,
 4, 7, 6,    4, 6, 5,
 3, 0, 1,    3, 1, 2

And replace the // Initialize GL State statements at the end of the engine_init_display function with this:

 // Initialize GL state.
 glClearColor(1.0f, 0.41f, 0.71f, 1.0f); // Hot pink! :D
 glViewport(0, 0, w, h);
 GLfloat ratio = (GLfloat)w / h;
 glFrustumf(-ratio, ratio, -1, 1, 1, 10);

Finally replace the engine_draw_frame function:

static void engine_draw_frame(struct engine* engine) {
 if (engine->display == NULL) {
  // No display.


 glTranslatef(0, 0, -3.0f);
 glRotatef(engine->state.angle * 0.25f, 1, 0, 0);  // X
 glRotatef(engine->state.angle, 0, 1, 0);          // Y


 glVertexPointer(3, GL_FIXED, 0, vertices);
 glColorPointer(4, GL_FIXED, 0, colors);
 glDrawElements(GL_TRIANGLES, 36, GL_UNSIGNED_BYTE, indices);
 eglSwapBuffers(engine->display, engine->surface);

You also might want to modify the angle increment so the cube rotates a bit faster, like engine.state.angle += 1.f;

Make sure the project is set to compile as x86 in order to use VS' own Android emulator.
Then F5 and enjoy the magic of the rotating cube.

Now try to add a breakpoint in your engine_draw_frame function. Yes, there's native debugging support for Android apps in Visual Studio 2015. Times are definitely changing at Microsoft.

Sample code

You can download the complete VS 2015 sample solution here.

More resources

This blog post is a nice overview of the new Visual C++ cross platform features.
This short Ch9 video gives a quick intro to the new Visual Studio 2015 C++ cross platform support.
NeHe is a quite old resource for OpenGL tutorials but mostly still useful.

Thursday, November 13, 2014

Cross Platform Mobile Development with C++ and Visual Studio 2015

Screenshot from Herb's video
Beside the Xamarin partnership and their great solutions for C# cross platform development, Microsoft is also heavily investing in C++ cross platform development with Visual Studio 2015.
With VS 2015 it's possible to build shared cross platform C++ libraries or even full native Android apps only with VS 2015. VS 2015 even ships its own Android emulator. iOS compiler support is supposed to be added as well.

Don't get me wrong, Xamarin and C# are without a doubt great for sharing code in native greenfield apps. However, existing code bases are often already built in C++. In fact I was involved in at least two large apps over the last 1.5 year which used already existing shared C++ layers. Most of the backend connectivity and core data logic was implemented in C++ and shared between WP, iOS, Android and BB10. Many large projects follow this shared C++ layers approach including the MS Office and Dropbox mobile apps.
Of course Xamarin C# and shared cross platform C++ libraries can be combined to get the best of all. For example by leveraging an existing code base for the shared C++ core libraries and Xamarin for the UI layer.

Is it the renaissance of C++? I'm not sure. It was always here driving many projects, even on the smallest devices and never gone, but I’m sure the new shared C++ library project support in VS 2015 is a strong commitment to the future of Visual C++.

Here's a good overview of the new C++ cross platform features in VS 2015:
Cross-Platform Mobile Development with Visual C++

And some very nice short videos from the Connect() event. Highly recommended to watch:
Herb's Ch9 video "C++:Conformance And Cross-Platform Mobile Development"
Ch9 video: "Visual C++ for Cross-Platform Mobile Development using Visual Studio 2015"

There's much more to discover in VS 2015 for C++ developers:
Visual Studio 2015 Preview is Now Available