HUD effect using a material

Hey. I’m trying to create a flashbang effect. I want to achieve this through a very bright texture that appears on your screen after th flash explodes, with the brightness depending on the distance. That’s all not a problem. The problem is that I want the texture to be brighter For different parts of the screen depending on the angle at which the player faces the flashbang. So the left side of the material should have a higher emissive value than the right side if the flash occurred on the left side. Any ideas on how to achieve this?