VoxeLibre/mods/MAPGEN/vl_terraforming/clearance_vm.lua
2024-10-29 19:41:33 +01:00

174 lines
6.5 KiB
Lua

local AIR = {name = "air"}
local abs = math.abs
local max = math.max
local floor = math.floor
local vector_new = vector.new
local is_solid_not_tree = vl_terraforming._is_solid_not_tree
local is_tree_not_leaves = vl_terraforming._is_tree_not_leaves
--- Clear an area for a structure
--
-- Rounding: we model an ellipse. At zero rounding, we want the line go through the corner, at sx/2, sz/2.
-- For this, we need to make ellipse sized 2a=sqrt(2)*sx, 2b=sqrt(2)*sz,
-- Which yields a = sx/sqrt(2), b=sz/sqrt(2) and a^2=sx^2*0.5, b^2=sz^2*0.5
-- To get corners, we decrease a and b by approx. corners each
-- The ellipse condition dx^2/a^2+dz^2/b^2 <= 1 then yields dx^2/(sx^2*0.5) + dz^2/(sz^2*0.5) <= 1
-- We use wx2=sx^-2*2, wz2=sz^-2*2 and then dx^2*wx2+dz^2*wz2 <= 1
--
-- @param vm VoxelManip: Lua voxel manipulator
-- @param px number: lowest x
-- @param py number: lowest y
-- @param pz number: lowest z
-- @param sx number: x width
-- @param sy number: y height
-- @param sz number: z depth
-- @param corners number: corner rounding
-- @param surface_mat Node: surface node material
-- @param dust_mat Node: surface dust material
-- @param pr PcgRandom: random generator
function vl_terraforming.clearance_vm(vm, px, py, pz, sx, sy, sz, corners, surface_mat, dust_mat, pr)
if sx <= 0 or sy <= 0 or sz <= 0 then return end
local get_node_at = vm.get_node_at
local set_node_at = vm.set_node_at
corners = corners or 0
local wx2, wz2 = max(sx - corners, 1)^-2 * 2, max(sz - corners, 1)^-2 * 2
local cx, cz = px + sx * 0.5 - 0.5, pz + sz * 0.5 - 0.5
local min_clear, max_clear = py+sy, py+floor(sy*1.5+2) -- todo: make more parameterizable, but adds another parameter
-- excavate the needed volume and some headroom
local vec = vector_new(0, 0, 0) -- single vector, to avoid allocations -- performance!
for xi = px-1,px+sx do
local dx = abs(cx-xi)
local dx2 = max(dx+0.51,0)^2*wx2
local dx21 = max(dx-0.49,0)^2*wx2
vec.x = xi
for zi = pz-1,pz+sz do
local dz = abs(cz-zi)
local dz2 = max(dz+0.51,0)^2*wz2
local dz21 = max(dz-0.49,0)^2*wz2
vec.z = zi
if xi >= px and xi < px+sx and zi >= pz and zi < pz+sz and dx2+dz2 <= 1 then
vec.y = py
if get_node_at(vm, vec).name ~= "mcl_core:bedrock" then set_node_at(vm, vec, AIR) end
vec.y = py - 1
local n = get_node_at(vm, vec)
if n and n.name ~= surface_mat.name and is_solid_not_tree(n) then
set_node_at(vm, vec, surface_mat)
end
for yi = py+1,min_clear do -- full height for inner area
vec.y = yi
if get_node_at(vm, vec).name ~= "mcl_core:bedrock" then set_node_at(vm, vec, AIR) end
end
elseif dx21+dz21 <= 1 then
-- widen the cave above by 1, to make easier to enter for mobs
-- todo: make configurable?
vec.y = py + 1
local name = get_node_at(vm, vec).name
if name ~= "mcl_core:bedrock" then
local mat = AIR
if dust_mat then
vec.y = py
if get_node_at(vm, vec).name == surface_mat.name then mat = dust_mat end
vec.y = py + 1
end
set_node_at(vm, vec, mat)
end
for yi = py+2,min_clear-1 do
vec.y = yi
if get_node_at(vm, vec).name ~= "mcl_core:bedrock" then set_node_at(vm, vec, AIR) end
if yi > py+4 then
local p = (yi-py) / (max_clear-py)
--minetest.log(tostring(p).."^2 "..tostring(p*p).." rand: "..pr:next(0,1e9)/1e9)
if (pr:next(0,1e9)/1e9) < p then break end
end
end
-- remove some tree parts and fix surfaces down
for yi = py,py-1,-1 do
vec.y = yi
local n = get_node_at(vm, vec)
if is_tree_not_leaves(n) then
set_node_at(vm, vec, surface_mat)
if dust_mat and yi == py then
vec.y = yi + 1
if get_node_at(vm, vec).name == "air" then set_node_at(vm, vec, dust_mat) end
end
else
if n and n.name ~= surface_mat.name and is_solid_not_tree(n) then
set_node_at(vm, vec, surface_mat)
if dust_mat then
vec.y = yi + 1
if get_node_at(vm, vec).name == "air" then set_node_at(vm, vec, dust_mat) end
end
end
break
end
end
end
end
end
-- some extra gaps for entry
-- todo: make optional instead of hard-coded 25%
-- todo: only really useful if there is space at px-3,py+3 to px-3,py+5
--[[
for xi = px-2,px+sx+1 do
local dx21 = max(abs(cx-xi)-0.49,0)^2*wx2
local dx22 = max(abs(cx-xi)-1.49,0)^2*wx2
for zi = pz-2,pz+sz+1 do
local dz21 = max(abs(cz-zi)-0.49,0)^2*wz2
local dz22 = max(abs(cz-zi)-1.49,0)^2*wz2
if dx21+dz21 > 1 and dx22+dz22 <= 1 and pr:next(1,4) == 1 then
if py+4 < sy then
for yi = py+2,py+4 do
vec = vector_new(xi, yi, zi)
if get_node_at(vm, vec).name ~= "mcl_core:bedrock" then set_node_at(vm, vec, v) end
end
end
for yi = py+1,py-1,-1 do
local n = get_node_at(vm, vector_new(xi, yi, zi))
if is_tree_bot_leaves(n) and n.name ~= "mcl_core:bedrock" then
set_node_at(vm, vector_new(xi, yi, zi), AIR)
else
if n and n.name ~= surface_mat.name and is_solid_not_tree(n) then
set_node_at(vm, vector_new(xi, yi, zi), surface_mat)
end
break
end
end
end
end
end
]]--
-- cave some additional area overhead, try to make it interesting though
for yi = min_clear+1,max_clear do
local dy2 = max(yi-min_clear-1,0)^2*0.05
local active = false
for xi = px-2,px+sx+1 do
local dx22 = max(abs(cx-xi)-1.49,0)^2*wx2
for zi = pz-2,pz+sz+1 do
local dz22 = max(abs(cz-zi)-1.49,0)^2*wz2
local keep_trees = (xi<px or xi>=px+sx) or (zi<pz or zi>=pz+sz) -- TODO make parameter?
if dx22+dy2+dz22 <= 1 then
vec.x, vec.y, vec.z = xi, yi, zi
local name = get_node_at(vm, vec).name
-- don't break bedrock or air
if name == "air" or name == "ignore" or name == "mcl_core:bedrock" or name == "mcl_villages:no_paths" then goto continue end
local meta = minetest.registered_items[name]
local groups = meta and meta.groups
local is_tree = groups.leaves or groups.tree or (groups.compostability or 0 > 50)
if keep_trees and is_tree then goto continue end
vec.y = yi-1
-- do not clear above solid
local name_below = get_node_at(vm, vec).name
if name_below ~= "air" and name_below ~= "ignore" and name_below ~= "mcl_core:bedrock" then goto continue end
-- try to completely remove trees overhead
-- stop randomly depending on fill, to narrow down the caves
if not keep_trees and not is_tree and (pr:next(0,1e9)/1e9)^0.5 > 1-(dx22+dy2+dz22-0.1) then goto continue end
vec.x, vec.y, vec.z = xi, yi, zi
set_node_at(vm, vec, AIR)
active = true
::continue::
end
end
end
if not active then break end
end
end