After giving you a brief introduction to graphics development on Android and our PowerVR Graphics SDK v3.0 r2, it’s now time to make our PowerVR-based device say “Hello”! There are several ways to do this, but in our opinion there is none like a plain triangle rendered on a coloured background!
For this exact purpose, the PowerVR Graphics SDK includes a simple C++ application called HelloAPI. The build steps for this project vary slightly depending on which SDK you have downloaded, so the following sections are split to accommodate both paths (prefixed with Option 1 and Option 2).
Option 1: Using the Android Manager add-in SDK
First, you will need to add the IMG_SDK_HOME environment variable for your NDK builds. To do so globally in Eclipse, click on Window and open the Preferences menu, navigate to C/C++ –> Build –> Environment and add the variable IMG_SDK_HOME, setting its value to the location the PowerVR Graphics SDK add-on is installed (typically under the add-ons directory inside the Android SDK). This variable only needs to be set once so the SDK’s Examples know where to find their build dependencies.
Note: The Android SDK integration required us to use Google’s preferred naming conventions for directories. Because of this, we’ve had to make a few changes, such as changing the “Examples” folder to “samples”
An Example can be imported by selecting the PowerVR Graphics SDK during the creation of a new Android sample project in Eclipse. For the purpose of this post, you should select the HelloAPI “sample” from the OpenGL ES 2.0 PowerVR Graphics SDK. Once the project has been imported, you must then right-click the <project name>->Android Tools->Add Native Support.
And that’s it! You can now use Eclipse’s build, deploy and debug functionality!
Option 2: Using the standard PowerVR Graphics SDK
The native build
First, open up a terminal and navigate to the Example project’s Android build directory. HelloAPI can be found here:
Next, you need to update the run the following on the first build to create local.properties:
android update project –p .-t [TARGET]
In the example above, [TARGET] must be replaced with the target ID of the platform version you want to target on your system. Available targets can be queried with the following command:
android list target
To use the ‘android’ tool you need to have the Android SDK’s platform-tools folder in your path. Once this is done, the application is then build in two stages. The first stage compiles the C++ code into a library. This is achieved using ‘ndk-build’, a tool included in the Android NDK. To compile for all supported platforms type:
On an a specific platform you can compile by typing:
Replacing [PLATFORM] with an entry from the following list of supported ABIs:
The second stage compiles the Java wrapper and creates the .apk file for installing on your device. The quickest way of achieving this is to type:
This will create an .apk file in ./bin and will handle the signing of your application for you (debug signing key is used).
(To create a release build, please see http://developer.android.com/guide/developing/other-ide.html#ReleaseMode)
Deploying the APK
To install the APK to your target device, you can use the ‘adb’ tool. This is found in the Android SDK’s platform-tools directory. You should add the platform-tools directory to your path so adb can be used from anywhere in the terminal.
To install the APK, open a terminal in the ./bin directory and run the following command:
adb install –r OGLES2HelloAPI-debug.apk
And that’s it!
You can launch the HelloAPI Example app on your device and witness the mighty yellow triangle rendered on a sky blue background! The example is trivial, but provides a good starting point for programmers new to 3D graphics and the OpenGL ES APIs.
Now that you know the basics, you can dive into the rest of the PowerVR Graphics SDK to learn new techniques and optimizations to improve your own applications. Happy coding!
The Android Diaries’ is a series of blog posts, articles and tutorials where we focus on all aspects of graphics development on Android, the Android SDK as well as Android-specific APIs like Renderscript or Filterscript. If you have any Android-related questions, ideas or suggestions, please leave a comment in the box below or start a discussion on our PowerVR-dedicated forum and we will get back to you as soon as possible. Make sure you also follow us on Twitter (@ImaginationPR and @PowerVRInsider) for the latest news and updates from Imagination and the PowerVR Insider developer programme.
Guillem Vinals Gangolells has contributed to this article.Follow @ImaginationTech