there is no "universal always right logic"
you must decide on how to do it, give each of the possible constellations a code and select the code to decide on how to blend it together ...
that or do it manually on a blend map this means a texture on which each of the 4 color channels defines the alpha value of the given vertex.
you must decide on how to do it, give each of the possible constellations a code and select the code to decide on how to blend it together ...
that or do it manually on a blend map this means a texture on which each of the 4 color channels defines the alpha value of the given vertex.