31 Mar 2015

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Power Great Gaming with New Analytics from Play Games

By Ben Frenkel, Google Play Games team

A few weeks ago at the Game Developers Conference (GDC), we announced Play Games Player Analytics, a new set of free reports to help you manage your games business and understand in-game player behavior. Today, we're excited to make these new tools available to you in the Google Play Developer Console.

Analytics is a key component of running a game as a service, which is increasingly becoming a necessity for running a successful mobile gaming business. When you take a closer look at large developers that do this successfully, you find that they do three things really well:

"With player engagement and revenue data living under one roof, developers get a level of data quality that is simply not available to smaller teams without dedicated staff. As the tools evolve, I think Google Play Games Player Analytics will finally allow indie devs to confidently make data-driven changes that actually improve revenue."

Kevin Pazirandeh
Developer of Zombie Highway 2

With Player Analytics, we wanted to make these capabilities available to the entire developer ecosystem on Google Play in a frictionless, easy-to-use way, freeing up your precious time to create great gaming experiences. Small studios, including the makers of Zombie Highway 2 and Bombsquad, have already started to see the benefits and impact of Player Analytics on their business.

Further, if you integrate with Google Play game services, you get this set of analytics with no incremental effort. But, for a little extra work, you can also unlock another set of high impact reports by integrating Google Play game services Events, starting with the Sources and Sinks report, a report to help you balance your in-game economy.

If you already have a game integrated with Google Play game services, go check out the new reports in the Google Play Developer Console today. For everyone else, enabling Player Analytics is as simple as adding a handful of lines of code to your game to integrate Google Play game services.

Manage your business to revenue targets

Set your spend target in Player Analytics by choosing a daily goal

To help assess the health of your games business, Player Analytics enables you to select a daily in-app purchase revenue target and then assess how you're doing against that goal through the Target vs Actual report depicted below. Learn more.

Identify hot spots using benchmarks with the Business Drivers report

Ever wonder how your game's performance stacks up against other games? Player Analytics tells you exactly how well you are doing compared to similar games in your category.

Metrics highlighted in red are below the benchmark. Arrows indicate whether a metric is trending up or down, and any cell with the icon can be clicked to see more details about the underlying drivers of the change. Learn more.

Track player retention by new user cohort

In the Retention report, you can see the percentage of players that continued to play your game on the following seven days after installing your game.

Learn more.

See where players are spending their time, struggling, and churning with the Player Progression report

Measured by the number of achievements players have earned, the Player Progression funnel helps you identify where your players are struggling and churning to help you refine your game and, ultimately, improve retention. Add more achievements to make progression tracking more precise.

Learn more.

Manage your in-game economy with the Sources and Sinks report

The Sources and Sinks report helps you balance your in-game economy by showing the relationship between how quickly players are earning or buying and using resources.

For example, Eric Froemling, one man developer of BombSquad, used the Sources & Sinks report to help balance the rate at which players earned and spent tickets.

Read more about Eric's experience with Player Analytics in his recent blog post.

To enable the Sources and Sinks report you will need to create and integrate Play game services Events that track sources of premium currency (e.g., gold coins earned), and sinks of premium currency (e.g., gold coins spent to buy in-app items).

31 Mar 2015 6:32pm GMT

26 Mar 2015

feedAndroid Developers Blog

Game Performance: Layout Qualifiers

Today, we want to share some best practices on using the OpenGL Shading Language (GLSL) that can optimize the performance of your game and simplify your workflow. Specifically, Layout qualifiers make your code more deterministic and increase performance by reducing your work.

Let's start with a simple vertex shader and change it as we go along.

This basic vertex shader takes position and texture coordinates, transforms the position and outputs the data to the fragment shader:

attribute vec4 vertexPosition;
attribute vec2 vertexUV;

uniform mat4 matWorldViewProjection;

varying vec2 outTexCoord;

void main()
{
  outTexCoord = vertexUV;
  gl_Position = matWorldViewProjection * vertexPosition;
}

Vertex Attribute Index

To draw a mesh on to the screen, you need to create a vertex buffer and fill it with vertex data, including positions and texture coordinates for this example.

In our sample shader, the vertex data may be laid out like this:

struct Vertex
{
  Vector4 Position;
  Vector2 TexCoords;
};

Therefore, we defined our vertex shader attributes like this:

attribute vec4 vertexPosition;
attribute vec2  vertexUV;

To associate the vertex data with the shader attributes, a call to glGetAttribLocation will get the handle of the named attribute. The attribute format is then detailed with a call to glVertexAttribPointer.

GLint handleVertexPos = glGetAttribLocation( myShaderProgram, "vertexPosition" );
glVertexAttribPointer( handleVertexPos, 4, GL_FLOAT, GL_FALSE, 0, 0 );

GLint handleVertexUV = glGetAttribLocation( myShaderProgram, "vertexUV" );
glVertexAttribPointer( handleVertexUV, 2, GL_FLOAT, GL_FALSE, 0, 0 );

But you may have multiple shaders with the vertexPosition attribute and calling glGetAttribLocation for every shader is a waste of performance which increases the loading time of your game.

Using layout qualifiers you can change your vertex shader attributes declaration like this:

layout(location = 0) in vec4 vertexPosition;
layout(location = 1) in vec2 vertexUV;

To do so you also need to tell the shader compiler that your shader is aimed at GL ES version 3.1. This is done by adding a version declaration:

#version 300 es

Let's see how this affects our shader, changes are marked in bold:

#version 300 es

layout(location = 0) in vec4 vertexPosition;
layout(location = 1) in vec2 vertexUV;

uniform mat4 matWorldViewProjection;

out vec2 outTexCoord;

void main()
{
  outTexCoord = vertexUV;
  gl_Position = matWorldViewProjection * vertexPosition;
}

Note that we also changed outTexCoord from varying to out. The varying keyword is deprecated from version 300 es and requires changing for the shader to work.

Note that Vertex Attribute qualifiers and #version 300 es are supported from OpenGL ES 3.0. The desktop equivalent is supported on OpenGL 3.3 and using #version 330.

Now you know your position attributes always at 0 and your texture coordinates will be at 1 and you can now bind your shader format without using glGetAttribLocation:

const int ATTRIB_POS = 0;
const int ATTRIB_UV   = 1;

glVertexAttribPointer( ATTRIB_POS, 4, GL_FLOAT, GL_FALSE, 0, 0 );
glVertexAttribPointer( ATTRIB_UV, 2, GL_FLOAT, GL_FALSE, 0, 0 );

This simple change leads to a cleaner pipeline, simpler code and saved performance during loading time.

To learn more about performance on Android, check out the Android Performance Patterns series.

Posted by Shanee Nishry, Games Developer Advocate

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26 Mar 2015 7:45pm GMT

25 Mar 2015

feedAndroid Developers Blog

Developing audio apps for Android Auto

Posted by Joshua Gordon, Developer Advocate

Have you ever wanted to develop apps for the car, but found the variety of OEMs and proprietary platforms too big of a hurdle? Now with Android Auto, you can target a single platform supported by vehicles coming soon from 28 manufacturers.

Using familiar Android APIs, you can easily add a great in-car user experience to your existing audio apps, with just a small amount of code. If you're new to developing for Auto, watch this DevByte for an overview of the APIs, and check out the training docs for an end-to-end tutorial.


Playback and custom controls


Custom playback controls on NPR One and iHeartRadio.

The first thing to understand about developing audio apps on Auto is that you don't draw your user interface directly. Instead, the framework has two well-defined UIs (one for playback, one for browsing) that are created automatically. This ensures consistent behavior across audio apps for drivers, and frees you from dealing with any car specific functionalities or layouts. Although the layout is predefined, you can customize it with artwork, color themes, and custom controls.

Both NPR One and iHeartRadio customize their UI. NPR One adds controls to mark a story as interesting, to view a list of upcoming stories, and to skip to the next story. iHeartRadio adds controls to favorite stations and to like songs. Both apps store user preferences across form factors.

Because the UI is drawn by the framework, playback commands need to be relayed to your app. This is accomplished with the MediaSession callback, which has methods like onPlay() and onPause(). All car specific functionality is handled behind the scenes. For example, you don't need to be aware if a command came from the touch screen, the steering wheel buttons, or the user's voice.

Browsing and recommendations


Browsing content on NPR One and iHeartRadio.

The browsing UI is likewise drawn by the framework. You implement the MediaBrowserService to share your content hierarchy with the framework. A content hierarchy is a collection of MediaItems that are either playable (e.g., a song, audio book, or radio station) or browsable (e.g., a favorites folder). Together, these form a tree used to display a browsable menu of your content.

With both apps, recommendations are key. NPR One recommends a short list of in-depth stories that can be selected from the browsing menu. These improve over time based on user feedback. iHeartRadio's browsing menu lets you pick from favorites and recommended stations, and their "For You" feature gives recommendations based on user location. The app also provides the ability create custom stations, from the browsing menu. Doing so is efficient and requires only three taps ("Create Station" -> "Rock" -> "Foo Fighters").

When developing for the car, it's important to quickly connect users with content to minimize distractions while driving. It's important to note that design considerations on Android Auto are different than on a mobile device. If you imagine a typical media player on a phone, you may picture a browsable menus of "all tracks" or "all artists". These are not ideal in the car, where the primary focus should be on the road. Both NPR One and iHeartRadio provide good examples of this, because they avoid deep menu hierarchies and lengthy browsable lists.

Voice actions for hands free operation

Voice actions (e.g., "Play KQED") are an important part of Android Auto. You can support voice actions in your app by implementing onPlayFromSearch() in the MediaSession.Callback. Voice actions may also be used to start your app from the home screen (e.g., "Play KQED on iHeartRadio"). To enable this functionality, declare the MEDIA_PLAY_FROM_SEARCH intent filter in your manifest. For an example, see this sample app.

Next steps

NPR One and iHeartRadio are just two examples of great apps for Android Auto today. They feel like a part of the car, and look and sound great. You can extend your apps to the car today, too, and developing for Auto is easy. The framework handles the car specific functionalities for you, so you're free to focus on making your app special. Join the discussion at http://g.co/androidautodev if you have questions or ideas to share. To get started on your app, visit developer.android.com/auto.

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25 Mar 2015 7:51pm GMT