I know that the blender game engine doesn't support real-time reflections, but I want to be able to make some areas of my gun model look like it has some edge wear (the paint is gone on the edges and the bare reflective metal underneath is visible), I have been able to achieve this effect in cycles with a sky color and just the diffuse color and a glossiness map generated in substance painter, it looked like this: So I tried to do basically the same thing in BGE (except I used the glossiness map image as a specular map) but it just looked more specular, which is not what I want. So I want to be able to use a reflection image, for instance a sky texture, like I did here: Except the fake reflection should only show up on the edges using a glossiness or a metalness map, like on the fisrt image. I know using a fake reflection like this is not very realistic, and I know it's still going to show a sky reflection even when the gun is inside a house or whatever, but I just want the edges to look like metal. Thanks in advance for any help you are able to provide.
Something you could do is use a node material and mix between a material and a reflection texture (here i map the reflection texture to the geometry normals but you might want to do something more realistic), using a metalness map as the mix factor.
here is a simple example image: