Best way to blend two render textures into a final render texture?

Questions & Answers
1

Hello, I have two render textures of the screen size, and I want to do an additive blending of the two to get the third render texture.

Now what I’m doing is using a UI Image like this:

  1. Create a camera and set the third render texture to its render target
  2. Create a screen space UI Image
  3. Set the Image’s material as my additive blending material which has two texture inputs
  4. Set my two render textures to the material inputs
  5. Give the Image an empty sprite
  6. The camera renders and I get the third texture

Although it does the job, but I feel the UI Image thing seems not natural. Is there a better way to do this?

2

Blend modes are mostly simple equations which are run on the pixel colour/ luminosity values for a couple of sets.

So its been a while since I have written shaders but I would assume that if the one you want is missing you would want to write a fragment/ pixel shader that takes the two textures and does what ever blending equation you need.

i.e. piping the pixel colour information from one images pixle (i.e. the first pixle at x:0,y:0) into one part of the equation and the same pixels colour information of the other image into the other part.

I have a list of them in my compositing book but I cant find an exhaustive list on the internet I am sure with a little bit of searching you could find any you need by looking for that specific one. You could use photoshop of equivalent to browse the different types of blend modes.

Here are some:

And here is a description of alot of them