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support "Stochastic L-systems"

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This commit is contained in:
Justin Lin 2020-04-14 12:16:43 +08:00
parent 2fb0710e4d
commit 074d526d10
2 changed files with 29 additions and 5 deletions
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30
src/experimental/_impl/_lsystem2_impl.scad
View File

@ -1,11 +1,33 @@
use <experimental/assoc_lookup.scad>;
use <turtle/turtle2d.scad>;
function _rule_n(range, leng, rand_n, i = 0) =
i == leng ? i :
rand_n < range[i] ? i + 1 : _rule_n(range, leng, rand_n, i + 1);
// It doesn't use recursion to avoid recursion error.
function _join(strs) =
let(leng = len(strs))
[for(i = 0, s = strs[0]; i < leng; i = i + 1, s = str(s, strs[i])) s][leng - 1];
function c_or_v(c, v, rand_n, rule, derived_pr, leng, i = 0) =
i == leng ? c : (
let(idx = search([v[i]], rule, num_returns_per_match=0, index_col_num = 1)[0][0])
rand_n < derived_pr[idx - 1] ? v[i] : c_or_v(c, v, rand_n, rule, derived_pr, leng, i + 1)
);
function _derive1_p(base, rule, derived_pr) =
let(rand_n = rands(0, 1, 1)[0])
_join([
for(c = base)
let(v = [for(r = rule) if(r[0] == c) r[1]])
v == [] ? c :
c_or_v(c, v, rand_n, rule, derived_pr, len(v))
]);
function _derive_p(base, rule, derived_pr, n, i = 0) =
i == n ? base : _derive_p(_derive1_p(base, rule, derived_pr), rule, derived_pr, n, i + 1);
function _derive1(base, rule) = _join([
for(c = base)
let(v = assoc_lookup(rule, c))
@ -15,8 +37,10 @@ function _derive1(base, rule) = _join([
function _derive(base, rule, n, i = 0) =
i == n ? base : _derive(_derive1(base, rule), rule, n, i + 1);
function derive(rule, n) =
_derive(assoc_lookup(rule, "S"), rule, n);
function _lsystem2_derive(rule, n, derived_pr) =
let(base = assoc_lookup(rule, "S"))
is_undef(derived_pr) ? _derive(base, rule, n) :
_derive_p(base, rule, derived_pr, n);
function _next_stack(t, code, stack) =
code == "[" ? concat([t], stack) :

4
src/experimental/lsystem2.scad
View File

@ -1,9 +1,9 @@
use <experimental/_impl/_lsystem2_impl.scad>;
use <turtle/turtle2d.scad>;
function lsystem2(rule, n, angle, leng = 1, heading = 0, start = [0, 0], forward_chars = "F") =
function lsystem2(rule, n, angle, leng = 1, heading = 0, start = [0, 0], forward_chars = "F", derived_pr) =
let(
derived = derive(rule, n),
derived = _lsystem2_derive(rule, n, derived_pr),
codes = forward_chars == "F" ? derived : _join([
for(c = derived)
let(idx = search(c, forward_chars))