Its not a simple grid division, once the bitmap is acquired , each patch is converted into a polygonal mesh , and for this mesh, 3 different levels of detail are computed, 100%, 50%,20% , red, green and blue , in the screenshot , its not a simple level of detail algorithm, it tries to mantain the shape of the current mesh, lowering the number of surfaces, at a required percentage, after that, a function for refinement of normals at border is executed, in fact without that , patches of terrain would be clearly visible.
I am working of making cracks disappearing.
i just loaded a 512x512 bitmap and it took 12 mins , but it is a big map to wander in it
Obviously, after the bitmap is processed i load the file containing processed meshes, i don't wait 12 mins to see modificiations
each time i run the program