NPOT vs POT nowadays, performance?

Hello guys,

First of all, sorry for my English.

We are using some postpro effects in our game, so we need to draw some Render Textures. The pipeline is:

• Draw Color to a full screen RT (same size as screen)
• Draw Depth to a full screen RT (same size as screen)
• Draw 2 passes Blur to a pair of 1/4 screen RT
  
• Draw the final result to the frame buffer using the Color RT, the Depth RT and the Blur RT as input

My doubts are about performance. Actually we are creating the RTs using the Screen Size ratio, so RTs are not NPOT. Is there any penalty on performance nowadays? Do you recommend using POT instead?

I'm aware of NPOT problems with compression storage, but they are Render Textures so there is no penalty on this.

We are targeting mid to high mobile devices.

Thanks in advance.

 

Hi, timely to find your post, since I have a mobile project that uses render textures extensively and I'm working on performance tuning because I'm getting awful framerates on my Huawei test device. (Performance on iOS is perfect at this point)

In fact, even a single render texture that fills about half the screen has a huge performance hit. The biggest bottleneck seems to be not the rendering itself but loading the texture onto the gpu, in other words texture (byte) size.

I got a pretty good performance boost switching to ARGB32 from ARGBHalf, which doesn't seem to affect the visual quality on my Android test device. (iOS on the other hand does require more precision for clean rendering so I've got a switch in my code now to use different formats per platform)

Also, when you create a render texture you can specify the number of bits to use for depth. Setting that to 0 or as low as possible got me another performance boost.

I plan to test POT vs NPOT tomorrow and will let you know what result I get. If you have any tips for optimizing render textures please let me know too!

 

saw this NPOT post last week,

https://forum.unity.com/threads/disadvantages-of-non-power-of-two-textures.814542/#post-5403687

 

Nice tips, thanks for sharing! I will try that half precision RT, looks a good boost performance. Please let me know about NPOT vs POT experiment, thanks a lot!!

 

Thanks for the link. As bgolus says (that man deserves a medal, my true hero) there isn’t too much info about internal gpu structure. Trying all different configurations for a RT looking for best performance is a bit hard because there will be different best configurations for each device.

 

Thank you! I will be using NPOT then