After starting to dig into ImageTargets example of Vuforia SDK, I noticed from the application log that my device was using OpenGL ES 2.0. I assumed that Android platform 2.1 was supporting OpenGL ES 2.0 already. But I read that Android SDK supports OpenGL ES 2.0 starting from Android version 2.2 (which is emphasized in this nice introduction from Android developers website. I recommend following this tutorial if you want to start coding on OpenGL ES 2.0 – that’s when I found out that GLES20 is not defined on Android 2.1).

How is my device using GLES 2.0? The answer is lying in NDK! Vuforia SDK examples are realizing all the rendering functions on NDK to increase graphics performance and Android NDK supports OpenGL ES 2.0 since March 2010 for Android devices 2.0 and higher (android_developer_ndk / revision 3 and engadget). Mystery solved 🙂

Have fun with GLES2.0!