Is it possible to use pixmaps on Android via Java API for GLES?

Question

I\'m trying to implement off-screen rendering with OpenGL ES on Android. My ultimate goal is to improve performance of texture mapping which I do in plain java and Bitmap/in

Answer 1

The best way to improve texture loading performance on Android is to use the EGL image extensions you sited and EGL_NATIVE_BUFFER_ANDROID with native code. I have a code example of that in this article. I measured major performance improvements with this approach.

Android has no support for Pixmaps and pbuffers do not work on Nvidia Tegra devices. You should use FBO-attached textures instead. That is the way the Android SurfaceTexture class is implemented.

If you need alpha textures, that is another reason to use native code. There is a compatibility problem between Bitmap and OpenGL ES with alpha textures.

Using hardware texture compression formats (ETC/PVR instead of PNG) and mipmaps improves the loading performance and quality of texture rendering a lot too, as discussed in this article.

The big problem is glReadPixels(). EGL_NATIVE_BUFFER_ANDROID only works for writing textures, not for reading them back to a Bitmap. Android's platform code uses glReadPixels() to implement TextureView.getBitmap() and it is very slow. The best solution is to not copy the texture to a Bitmap, but to display the rendered TextureView directly which avoids glReadPixels().

I have been working with OpenGL ES 2.0 and the situation may have been improved with 3.0.