Minetest - VoxelArea benchmark

a.lua

VoxelArea = {
	MinEdge = {x=1, y=1, z=1},
	MaxEdge = {x=0, y=0, z=0},
	ystride = 0,
	zstride = 0,
}

function VoxelArea:new(o)
	o = o or {}
	setmetatable(o, self)
	self.__index = self

	local e = o:getExtent()
	o.ystride = e.x
	o.zstride = e.x * e.y

	return o
end

function VoxelArea:getExtent()
	local MaxEdge, MinEdge = self.MaxEdge, self.MinEdge
	return {
		x = MaxEdge.x - MinEdge.x + 1,
		y = MaxEdge.y - MinEdge.y + 1,
		z = MaxEdge.z - MinEdge.z + 1,
	}
end

function VoxelArea:getVolume()
	local e = self:getExtent()
	return e.x * e.y * e.z
end

function VoxelArea:index(x, y, z)
	local MinEdge = self.MinEdge
	local i = (z - MinEdge.z) * self.zstride +
			  (y - MinEdge.y) * self.ystride +
			  (x - MinEdge.x) + 1
	return math.floor(i)
end

function VoxelArea:indexp(p)
	local MinEdge = self.MinEdge
	local i = (p.z - MinEdge.z) * self.zstride +
			  (p.y - MinEdge.y) * self.ystride +
			  (p.x - MinEdge.x) + 1
	return math.floor(i)
end

function VoxelArea:position(i)
	local p = {}
	local MinEdge = self.MinEdge

	i = i - 1

	p.z = math.floor(i / self.zstride) + MinEdge.z
	i = i % self.zstride

	p.y = math.floor(i / self.ystride) + MinEdge.y
	i = i % self.ystride

	p.x = math.floor(i) + MinEdge.x

	return p
end

function VoxelArea:contains(x, y, z)
	local MaxEdge, MinEdge = self.MaxEdge, self.MinEdge
	return (x >= MinEdge.x) and (x <= MaxEdge.x) and
		   (y >= MinEdge.y) and (y <= MaxEdge.y) and
		   (z >= MinEdge.z) and (z <= MaxEdge.z)
end

function VoxelArea:containsp(p)
	local MaxEdge, MinEdge = self.MaxEdge, self.MinEdge
	return (p.x >= MinEdge.x) and (p.x <= MaxEdge.x) and
		   (p.y >= MinEdge.y) and (p.y <= MaxEdge.y) and
		   (p.z >= MinEdge.z) and (p.z <= MaxEdge.z)
end

function VoxelArea:containsi(i)
	return (i >= 1) and (i <= self:getVolume())
end

function VoxelArea:iter(minx, miny, minz, maxx, maxy, maxz)
	local i = self:index(minx, miny, minz) - 1
	local xrange = maxx - minx + 1
	local nextaction = i + 1 + xrange

	local y = 0
	local yrange = maxy - miny + 1
	local yreqstride = self.ystride - xrange

	local z = 0
	local zrange = maxz - minz + 1
	local multistride = self.zstride - ((yrange - 1) * self.ystride + xrange)

	return function()
		-- continue i until it needs to jump
		i = i + 1
		if i ~= nextaction then
			return i
		end

		-- continue y until maxy is exceeded
		y = y + 1
		if y ~= yrange then
			-- set i to index(minx, miny + y, minz + z) - 1
			i = i + yreqstride
			nextaction = i + xrange
			return i
		end

		-- continue z until maxz is exceeded
		z = z + 1
		if z == zrange then
			-- cuboid finished, return nil
			return
		end

		-- set i to index(minx, miny, minz + z) - 1
		i = i + multistride

		y = 0
		nextaction = i + xrange
		return i
	end
end

function VoxelArea:iterp(minp, maxp)
	return self:iter(minp.x, minp.y, minp.z, maxp.x, maxp.y, maxp.z)
end

local function xyz(v) return { x=v, y=v, z=v } end

local function timeit(f, count)
	count = count or 5000
	local start = os.clock()
	for i = 1, count do
		f()
	end
	return os.clock()-start
end

local function test_table()
	local va = VoxelArea:new({ MinEdge=xyz(0), MaxEdge=xyz(15) })
	local c = 0
	for x = 0, 15 do
	for y = 0, 15 do
	for z = 0, 15 do
		c = c + va:index(x, y, z)
	end -- z
	end -- y
	end -- x
	assert(c == 8390656)
end


local function va_indexer(minedge, maxedge)
	local bx = minedge.x
	local by = minedge.y
	local bz = minedge.z
	local dx = maxedge.x - bx + 1
	local dy = maxedge.y - by + 1
	local dz = maxedge.z - bz + 1
	local ystride = dx
	local zstride = dx * dy
	local floor = math.floor

	return function(x, y, z)
		return floor((z - bz) * zstride +
				(y - by) * ystride +
				(x - bx) + 1)
	end
end

local function test_local()
	local index = va_indexer(xyz(0), xyz(15))
	local c = 0
	for x = 0, 15 do
	for y = 0, 15 do
	for z = 0, 15 do
		c = c + index(x, y, z)
	end -- z
	end -- y
	end -- x
	assert(c == 8390656)
end

print("VoxelArea:", timeit(test_table))
print("local:", timeit(test_local))

-- # luajit -v va.lua 
-- LuaJIT 2.0.4 -- Copyright (C) 2005-2015 Mike Pall. http://luajit.org/
-- VoxelArea:	0.257723
-- local:	0.260472
--
-- # lua -v va.lua
-- Lua 5.1.5  Copyright (C) 1994-2012 Lua.org, PUC-Rio
-- VoxelArea:	12.892612
-- local:	6.059025