Hey, I was creating a simple decal material which should show my generated QR code in a texture parameter. No problem at all. I created the material, and thats how it is finished (pretty simple):
I just tried that out, but still the same problem. Also, that would’nt be the perfect solution as I need to place those decals dynamicially at runtime.
You are rotating your Decal into indirect lighting and the type of decal you are using will not render in indirect lighting. Take a look at this Answer for details on how to get the decal to render the way you want it to: