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Support arbitrary expressions in perlin noise rendering script.

develop
Alexander Gavrilov 2013-10-09 20:56:46 +04:00
parent bed1e00a6e
commit 3cfbb13afd
1 changed files with 108 additions and 54 deletions
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162
scripts/devel/test-perlin.lua
Unescape Escape View File

@ -4,61 +4,117 @@ local args = {...}
local rng = dfhack.random.new(3)
if #args < 3 then
qerror('Usage: devel/test-perlin <fname.pgm> <density> <coeff|expr...x[...y[...z]]>...')
qerror('Usage: devel/test-perlin <fname.pgm> <density> <expr> [-xy <xyscale>] [-z <zscale>]')
end
local fname = table.remove(args,1)
local goal = tonumber(table.remove(args,1)) or qerror('Invalid density')
local expr = table.remove(args,1) or qerror('No expression')
local zscale = 2
local xyscale = 1
local zscale = 6
local coeffs = {}
local fns = {}
for i = 1,#args,2 do
if args[i] == '-xy' then
xyscale = tonumber(args[i+1]) or qerror('Invalid xyscale')
end
if args[i] == '-z' then
zscale = tonumber(args[i+1]) or qerror('Invalid zscale')
end
end
local env = copyall(math)
env.apow = function(x,y) return math.pow(math.abs(x),y) end
local fn_env = copyall(math)
fn_env.rng = rng
fn_env.apow = function(x,y) return math.pow(math.abs(x),y) end
fn_env.spow = function(x,y) return x*math.pow(math.abs(x),y-1) end
-- Noise functions are referenced from expressions
-- as variables of form like "x3a", where:
-- 1) x is one of x/y/z/w independent functions in each octave
-- 2) 3 is the octave number; 0 corresponds to the whole range
-- 3) a is the subtype
-- Independent noise functions: support 4
local ids = { 'x', 'y', 'z', 'w' }
-- Subtype: provides an offset to the coordinates
local subs = {
[''] = { 0, 0, 0 },
a = { 0.5, 0, 0 },
b = { 0, 0.5, 0 },
c = { 0.5, 0.5, 0 },
d = { 0, 0, 0.5 },
e = { 0.5, 0, 0.5 },
f = { 0, 0.5, 0.5 },
g = { 0.5, 0.5, 0.5 },
}
function mkdelta(v)
if v == 0 then
return ''
else
return '+'..v
end
end
for i = 1,#args do
local fn = rng:perlin(3);
local fn2 = rng:perlin(3);
local fn3 = rng:perlin(3);
local fn4 = rng:perlin(3);
function mkexpr(expr)
-- Collect referenced variables
local max_octave = -1
local vars = {}
fns[i] = fn;
for var,id,octave,subtype in string.gmatch(expr,'%f[%w](([xyzw])(%d+)(%a*))%f[^%w]') do
if not vars[var] then
octave = tonumber(octave)
local val = string.match(args[i],'^([+-]?[%d.]+)$')
if val then
coeffs[i] = function(x) return x * val end
else
local argstr = 'x'
if string.match(args[i], '%f[%w]w%f[^%w]') then
argstr = 'x,y,z,w'
fns[i] = function(x,y,z)
return fn(x,y,z), fn2(x,y,z), fn3(x+0.5,y+0.5,z+0.5), fn4(x+0.5,y+0.5,z+0.5)
end
elseif string.match(args[i], '%f[%w]z%f[^%w]') then
argstr = 'x,y,z'
fns[i] = function(x,y,z)
return fn(x,y,z), fn2(x,y,z), fn3(x+0.5,y+0.5,z+0.5)
end
elseif string.match(args[i], '%f[%w]y%f[^%w]') then
argstr = 'x,y'
fns[i] = function(x,y,z)
return fn(x,y,z), fn2(x,y,z)
if octave > max_octave then
max_octave = octave
end
local sub = subs[subtype] or qerror('Invalid subtype: '..subtype)
vars[var] = { id = id, octave = octave, subtype = subtype, sub = sub }
end
end
if max_octave < 0 then
qerror('No noise function references in expression.')
end
local f,err = load(
'return function('..argstr..') return ('..args[i]..') end',
'=(expr)', 't', env
)
if not f then
qerror(err)
-- Allocate the noise functions
local code = ''
for i = 0,max_octave do
for j,id in ipairs(ids) do
code = code .. 'local _fn_'..i..'_'..id..' = rng:perlin(3)\n';
end
coeffs[i] = f()
end
-- Evaluate variables
code = code .. 'return function(x,y,z)\n'
for var,info in pairs(vars) do
local fn = '_fn_'..info.octave..'_'..info.id
local mul = math.pow(2,info.octave)
mul = math.min(48*4, mul)
code = code .. ' local '..var
.. ' = _fn_'..info.octave..'_'..info.id
.. '(x*'..mul..mkdelta(info.sub[1])
.. ',y*'..mul..mkdelta(info.sub[2])
.. ',z*'..mul..mkdelta(info.sub[3])
.. ')\n'
end
-- Complete and compile the function
code = code .. ' return ('..expr..')\nend\n'
local f,err = load(code, '=(expr)', 't', fn_env)
if not f then
qerror(err)
end
return f()
end
local field_fn = mkexpr(expr)
function render(thresh,file)
local area = 0
local line, arr = '', {}
@ -68,16 +124,10 @@ function render(thresh,file)
line = ''
for zx = 0,1 do
for x = 0,48*4-1 do
local tx = (0.5+x)/(48*2)
local ty = (0.5+y)/(48*2)
local tz = 0.5+(zx+zy*2)/(48*2/zscale)
local v1 = 0
for i = 1,#coeffs do
v1 = v1 + coeffs[i](fns[i](tx,ty,tz))
tx = tx*2
ty = ty*2
tz = tz*2
end
local tx = (0.5+x)/(48*4/xyscale)
local ty = (0.5+y)/(48*4/xyscale)
local tz = 0.3+(zx+zy*2)/(48*4/zscale)
local v1 = field_fn(tx, ty, tz)
local v = -1
if v1 > thresh then
v = v1;
@ -103,12 +153,13 @@ function render(thresh,file)
end
function search(fn,min,max,goal,eps)
while true do
local center = (max+min)/2
local center
for i = 1,32 do
center = (max+min)/2
local cval = fn(center)
print('At '..center..': '..cval)
if math.abs(cval-goal) < eps then
return center
break
end
if cval > goal then
min = center
@ -116,16 +167,19 @@ function search(fn,min,max,goal,eps)
max = center
end
end
return center
end
local thresh = search(render, -1, 1, goal, 0.001)
local thresh = search(render, -2, 2, goal, math.min(0.001,goal/20))
local file,err = io.open(fname, 'wb')
if not file then
print('error: ',err)
return
end
file:write('P5\n768 768\n255\n')
file:write('P5\n')
file:write('# '..goal..' '..expr..' '..xyscale..' '..zscale..'\n')
file:write('768 768\n255\n')
local area = render(thresh, file)
file:close()