How to paint a surface ingame?

What I’m trying to do:

I have a few balloons that are supposedly filled with color and I want to be able to pop them and paint the surface underneath with a certain color. I also want the paint splatter shape to be somewhat random, preferably procedurally generated, and I want the colors to mingle and mix when two different colors fall on the same spot. No real fluid simulation or anything like that tho, just spawn a random splatter on a surface and control how it blends with the background. First priority is the painting, second is the blending and third the randomness- I could fake the last one.

What I did

  1. The best solution I found even after hours of searching is spawning some decals. The problem with that is that there are not many blend options with decals and (I think I’ll need to code the blending myself but I don’t know where and how to do that. For example where blue and yellow intersect I’d like to show grass or something) and by spawning decals for a long time I would assume that the place will get so full of actors that its gonna lag like hell. All this is intended for an android game btw so I cant go extremely heavy.

  2. I tried vertex painting the colors and textures I want but the resolution is too bad and I cant exactly paint a 1 million poly surface just to make it look crisp enough.

What I’m searching:

  1. Any way to paint on a texture or simulate paint on it in a reasonably good resolution.

  2. Any way to bake decals on runtime on a texture so I dont have a million actors, and how to edit their blending options.

  3. Any way to create procedurally create splatter patterns. (I don’t necessarily want the code if thats the only way, just where to put it, what function or class I can edit etc.)

  4. Any other idea on how I could accomplish what I’m describing on the first paragraph of this question.

Buuuuuuump

Hi I am looking for similar solution for my school project Could you please post me any materials you find or get about that, if any.