make precalc make sense

README.md

@@ -175,16 +175,40 @@ if the position passed to `luamap.logic` is outside of the y-range, then
 sure to set the y-range to completely encompass the range that you expect to
 find your noises. 
 
+
 ### luamap.precalc
 
 ```lua
 luamap.precalc(data, area, vm, minp, maxp, seed)
 ```
 
+DESCRIPTION: An overridable function called just before calculating the noise
+and calling the logic function for each node.  Best practice is to save the old
+function and call it before adding one's own logic, just like with
+`luamap.logic`
+
+
+### luamap.postcalc
+
+```lua
+luamap.postcalc(data, area, vm, minp, maxp, seed)
+```
+
 DESCRIPTION: An overridable function called just before setting the map lighting
-and data. It offers compatability with biomegen, which needs these parameters to
-function. Best practice is to save the old function and call it before adding
-one's own logic, just like with `luamap.logic`
+and data after the noise has been calculated and luamap.logic has been called
+for each node in the mapblock. It offers compatability with biomegen by Gaël de
+Sailly, which needs these parameters to function. Best practice is to save the
+old function and call it before adding one's own logic, just like with
+`luamap.logic`
+
+example:
+```lua
+local old_postcalc = luamap.precalc
+function luamap.postcalc(data, area, vm, minp, maxp, seed)
+    old_postcalc(data, area, vm, minp, maxp, seed)
+    biomegen.generate_all(data, area, vm, minp, maxp, seed)
+end
+```
 
 ### luamap.set_singlenode
 

init.lua

@@ -50,6 +50,12 @@ function luamap.precalc(data, area, vm, minp, maxp, seed)
     return
 end
 
+-- override this function
+function luamap.postcalc(data, area, vm, minp, maxp, seed)
+    return
+end
+
+
 
 -- Set mapgen parameters
 function luamap.set_singlenode()
@@ -78,6 +84,8 @@ minetest.register_on_generated(function(minp, maxp, seed)
 	local minpos3d = {x=minp.x, y=minp.y-16, z=minp.z}
 	local minpos2d = {x=minp.x, y=minp.z}
 	
+	luamap.precalc(data, area, vm, minp, maxp, seed)
+
     for name,elements in pairs(noises_2d) do
 		if emin.y >= elements.ymin and emax.y <= elements.ymax then
 			noises_2d[name].nobj = noises_2d[name].nobj or minetest.get_perlin_map(noises_2d[name].np_vals, chulens2d)
@@ -132,7 +140,7 @@ minetest.register_on_generated(function(minp, maxp, seed)
 		end
 		i3dz=i3dz+zstride
 	end
-	luamap.precalc(data, area, vm, minp, maxp, seed)
+	luamap.postcalc(data, area, vm, minp, maxp, seed)
 	vm:set_data(data)
 	vm:calc_lighting()
 	vm:write_to_map(data)