mtcontrib/mapgen_rivers
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Use local variables for math.* functions

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and remove an unnecessary index calculation
This commit is contained in:
Gael-de-Sailly
2022-01-03 11:56:16 +01:00
parent 2e29474686
commit f8f467ac3f
3 changed files with 43 additions and 34 deletions
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35
polygons.lua
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@ -90,16 +90,19 @@ if mapgen_rivers.settings.center then
map_offset.z = blocksize*Z/2
end
-- Localize for performance
local floor, ceil, min, max, abs = math.floor, math.ceil, math.min, math.max, math.abs
local min_catchment = mapgen_rivers.settings.min_catchment / (blocksize*blocksize)
local wpower = mapgen_rivers.settings.river_widening_power
local wfactor = 1/(2*blocksize * min_catchment^wpower)
local function river_width(flow)
flow = math.abs(flow)
flow = abs(flow)
if flow < min_catchment then
return 0
end
return math.min(wfactor * flow ^ wpower, 1)
return min(wfactor * flow ^ wpower, 1)
end
local noise_heat -- Need a large-scale noise here so no heat blend
@ -138,8 +141,8 @@ local function make_polygons(minp, maxp)
local polygons = {}
-- Determine the minimum and maximum coordinates of the polygons that could be on the chunk, knowing that they have an average size of 'blocksize' and a maximal offset of 0.5 blocksize.
local xpmin, xpmax = math.max(math.floor((minp.x+map_offset.x)/blocksize - 0.5), 0), math.min(math.ceil((maxp.x+map_offset.x)/blocksize + 0.5), X-2)
local zpmin, zpmax = math.max(math.floor((minp.z+map_offset.z)/blocksize - 0.5), 0), math.min(math.ceil((maxp.z+map_offset.z)/blocksize + 0.5), Z-2)
local xpmin, xpmax = max(floor((minp.x+map_offset.x)/blocksize - 0.5), 0), min(ceil((maxp.x+map_offset.x)/blocksize + 0.5), X-2)
local zpmin, zpmax = max(floor((minp.z+map_offset.z)/blocksize - 0.5), 0), min(ceil((maxp.z+map_offset.z)/blocksize + 0.5), Z-2)
-- Iterate over the polygons
for xp = xpmin, xpmax do
@ -165,8 +168,8 @@ local function make_polygons(minp, maxp)
local bounds = {} -- Will be a list of the intercepts of polygon edges for every Z position (scanline algorithm)
-- Calculate the min and max Z positions
local zmin = math.max(math.floor(math.min(unpack(poly_z)))+1, minp.z)
local zmax = math.min(math.floor(math.max(unpack(poly_z))), maxp.z)
local zmin = max(floor(min(unpack(poly_z)))+1, minp.z)
local zmax = min(floor(max(unpack(poly_z))), maxp.z)
-- And initialize the arrays
for z=zmin, zmax do
bounds[z] = {}
@ -176,14 +179,14 @@ local function make_polygons(minp, maxp)
for i2=1, 4 do -- Loop on 4 edges
local z1, z2 = poly_z[i1], poly_z[i2]
-- Calculate the integer Z positions over which this edge spans
local lzmin = math.floor(math.min(z1, z2))+1
local lzmax = math.floor(math.max(z1, z2))
local lzmin = floor(min(z1, z2))+1
local lzmax = floor(max(z1, z2))
if lzmin <= lzmax then -- If there is at least one position in it
local x1, x2 = poly_x[i1], poly_x[i2]
-- Calculate coefficient of the equation defining the edge: X=aZ+b
local a = (x1-x2) / (z1-z2)
local b = (x1 - a*z1)
for z=math.max(lzmin, minp.z), math.min(lzmax, maxp.z) do
for z=max(lzmin, minp.z), min(lzmax, maxp.z) do
-- For every Z position involved, add the intercepted X position in the table
table.insert(bounds[z], a*z+b)
end
@ -194,11 +197,11 @@ local function make_polygons(minp, maxp)
-- Now sort the bounds list
local zlist = bounds[z]
table.sort(zlist)
local c = math.floor(#zlist/2)
local c = floor(#zlist/2)
for l=1, c do
-- Take pairs of X coordinates: all positions between them belong to the polygon.
local xmin = math.max(math.floor(zlist[l*2-1])+1, minp.x)
local xmax = math.min(math.floor(zlist[l*2]), maxp.x)
local xmin = max(floor(zlist[l*2-1])+1, minp.x)
local xmax = min(floor(zlist[l*2]), maxp.x)
local i = (z-minp.z) * chulens + (xmin-minp.x) + 1
for x=xmin, xmax do
-- Fill the map at these places
@ -220,16 +223,16 @@ local function make_polygons(minp, maxp)
local riverD = river_width(rivers[iD])
if glaciers then -- Widen the river
if get_temperature(poly_x[1], poly_dem[1], poly_z[1]) < 0 then
riverA = math.min(riverA*glacier_factor, 1)
riverA = min(riverA*glacier_factor, 1)
end
if get_temperature(poly_x[2], poly_dem[2], poly_z[2]) < 0 then
riverB = math.min(riverB*glacier_factor, 1)
riverB = min(riverB*glacier_factor, 1)
end
if get_temperature(poly_x[3], poly_dem[3], poly_z[3]) < 0 then
riverC = math.min(riverC*glacier_factor, 1)
riverC = min(riverC*glacier_factor, 1)
end
if get_temperature(poly_x[4], poly_dem[4], poly_z[4]) < 0 then
riverD = math.min(riverD*glacier_factor, 1)
riverD = min(riverD*glacier_factor, 1)
end
end