Compositing two images-as-planes in viewport to set mix mode

Hello,
I have two images as planes in my orthogonal scene. One is as a background and the second one is on the background one. I want to mix them, so the second one is set on mix mode darken, as I would do with mix node in compositing, but in this case instead of two input nodes I have the images in the scene. I don’t know how to set things to do this. Also I would like to see the result in viewport, but I guess this isn’t problem with the new real-time renderer. I’ve used Blender before, but that was a year or more ago, and I’ve forgot things. I’m using Blender 2.82a.
Thanks for help

Edit: It looks like the right way to do what I want is materials. I have to make a material for the second image-as-plane to act as the blend mode between the two images is set on darken. In material node tree is a node MixRGB that I’m using. The problem is that I dont know how to input the color thats behind the second image ( that is the background image), so now I mix it only with pure color.
Here is my node setup for the second image:


Color2 input is where I want to add what’s behind the material.

Edit 2: I moved this from Compositing and Post Processing, I think fits here better.

Edit 3: SOLUTION:

Screenshot_20200714_121629 Screenshot_20200714_121735
It is simple, but for some reason I couldn’t come up with this for days. :upside_down_face: :roll_eyes:

I understand your frustration because it sounds like something I was trying to do but I’m not sure of exactly what you problem or desired goal is and how these settings in the screenshots work. Coud you post the result?

As far as I can tell there’s no way to get individual 3d objects’ pixels to interact with each other in a blending mode kind of way. If it could do that there would be a huge number of new motion graphics things that would be as easy to do in Blender as they are in After Effects.

Unless your image-as-plane object is very close to other objects and would be casting light upon them you don’t need to use the IAP shadeless node. You can just plug the image direclty into the surface of the Material Output node.

FYI You can use texture coordinate nodes set to object and pick an object in your 3d scene and use that to move textures around within the 2d material.