OpenGL ES vs OpenCL vs RenderScript for Android Image Processing

Question

I need to build an Image processing application for Android. Performance is the main requirement and I am looking to use gpu compute. I want to know which of the 3 libraries is best to use.

I know OpenGL is primarily for graphics but also supports computer shaders.

I am not sure how well supported OpenCL is on Android

RenderScript lacks documentation and I think is slower than other libraries.

Answer 1

For an Image Processing App, the heaviest part is in the processing (transforming/manipulating) the pixels of images in memory, not rendering images to screens/buffers.

Sure, that kind of processing is general and needs a general-purpose computation API.

Thus, we can eliminate OpenGL ES. It supports shaders, but the OpenGL ES Shading Language is very limited and definitely not suitable for general processing.

RenderScript, according to this:

RenderScript does not use any GPU or DSPs cores. That is a common misconception encouraged by Google's deliberately vague documentation. RenderScript used to have an interface to OpenGL ES, but that has been deprecated and has never been used for much beyond animated wallpapers. RenderScript will use multiple CPU cores, if available, but I suspect RenderScript will be replaced by OpenCL.

I'm working for a big video game company, we don't have any plan to use RenderScript. We think Vulkan is a better choice. I suggest you choose Vulkan too but the problem is that the number of Android devices supporting Vulkan is pretty low now.

Therefore, to answer your question, please go with OpenCL. Although OpenCL is not part of the Android platform, many manufacturers provide drivers or even SDKs to support OpenCL on Android. At least, it is better than Vulkan in terms of number of supported devices.