Yes you could definitely do this differently if you don’t need to do it on the fly. I fade into my levels which will have player’s creatures in them so I have to do it on the fly.

Obviously, you don’t want to waste memory loading a completely separate texture so you could just store a greyscale copy of the blurred map inside the alpha channel of the main map image (which doesn’t look like it’s being used).

Texture lookups in a shader are expensive so this would save you all the ones you need to blur the image as well as the second texture lookup to sample from a separate blur texture.

Additionally, this would allow your artist to customize the fade animation. For example, blurring the image and then applying gradient (with “multiply” blending) would make the image be drawn in with a direction that follows the gradient (i.e. left to right, from center, etc) which could be customized for each art asset you want to use the effect on. Or manually trace the lines with a gradient brush and the image will fade in like it’s being drawn.

Sorry for the novel, but hopefully that made sense. I’m just a graphics/digital art guy who happened to stumble on your blog and thought your art design for this game pretty great. Keep up the good work.