Question Can I draw render texture without graphics.blit

Hello there. I am trying to doing some sort of field-calculation base on a render texture.

I need to do this every frame:

Code (CSharp):

1. while ()
2.         {          
3.             Graphics.Blit(tex0, tex1, _material);          
4.         }

Document mention Graphics.Blit draws a full-screen quad. If I loop for 30 times, this will cause performance problem. Is there a more efficient way to do this?

 

Don't do it 30 times?

You'll need to be more specific about what you're trying to accomplish. Not necessarily in terms of what you're currently doing, but what the end goal is.

 

I am trying to generate sdf base on render texture capture by the camera. I found the jump flood algorithm.
https://github.com/leapmotion/AppExperiments/tree/master/Assets/AppModules/ScreenSpaceDistanceField

Edit: Oh, I think I can loop in fragment shader for 30 times.

 

There's no reason to run that 30 times. 12 times is kind of the upper bounds of the max number of times you'd need to run it, as that would entirely flood fill a 4096 x 4096 texture from a single pixel in a corner. 30 iterations would flood fill a 1,073,741,824 x 1,073,741,824 texture!

Depending on your needs, you may want to do your flood fill at a lower resolution, or at least calculate the max number of iterations you need for the resolution you're rendering at.

 

Thanks for the reply. SDF is only the first part of what I am trying to do. I am trying to do accumulated SDF, so it is actually vector-distance field. I need to run SDF twice then superposition then SDF again.