Does OpenGL ES drain more battery than standard 2D graphics?

Question

I'm contemplating writing an app which does a lot of moving 2D graphics. I'm not very familiar with the standard android 2D graphics API, and I'm a lot more comfortable with OpenGL so I'm naturally considering using OpenGL instead.

My consideration right now is this, if I make sure to reduce my frame rate and not do any continuous updates unless I need to animate stuff, is there a significant difference in power consumption/battery life with using OpenGL ES compared to standard graphics?

Note that I'm not making a game, and I will not need continuous updates except when animating UI elements.

Answer 1

OpenGL-ES on most devices leverages the device's GPU, and therefore likely has a slightly higher battery usage than non-OpenGL-ES display systems, however I believe that this is a negligible difference. Usually battery strain considerations circle areas such as networking or GPS tracking. For graphics, the best approach to minimizing battery consumption would be minimizing the overall usage of the device's CPU.

OpenGL-ES is optimized to be as efficient as possible for heavy graphic rendering, and has a bonus advantage of running outside the sandbox Android allocates to each running app, granting it a much larger pool of memory, along with access to the GPU making it optimal when considering a graphic rich presentation layer in your app.

Barring OpenGL-ES, you would probably either want to work with Bitmaps & Canvases or work with Views nested inside ViewGroups and move them around by altering their LayoutParams, or manipulating their Matrices in order to animate objects around the screen. Performance-wise, animations which are done like this are rarely impressive when compared with animations performed by OpenGL based platforms.

On the other hand, managing a structured app entirely in OpenGL-ES could be a nightmare as well. Using Fragments and Views are always the method of choice when building a non-graphic rich app, simply because they make everything so much simpler, and they were built and optimized for exactly this purpose.

At the end, it really depends on the requirements of the app you're building. You could also consider developing certain segments which have higher graphical requirements in OpenGL-ES and others which do not in more conventional methods such as Fragments.

Battery-wise, utilizing the GPU via OpenGL-ES definitely has some overhead, but if you overclock the CPU using conventional animation methods, you may end up putting even more strain on the battery, and even damaging your app's user experience with low frame rates.