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Add hacky example of (incorrect) double spiral in twist()

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This commit is contained in:
Chris Hodapp 2020-03-27 23:00:24 -04:00
parent 96f8004df2
commit 21ce55d141
3 changed files with 55 additions and 32 deletions
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74
src/examples.rs
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@ -3,7 +3,7 @@ use nalgebra::*;
//pub mod examples;
use crate::openmesh::{OpenMesh, Tag, Mat4, Vertex, vertex, transform};
use crate::rule::{Rule, RuleEval, Child};
use crate::rule::{Rule, RuleFn, RuleEval, Child};
use crate::prim;
use crate::util;
use crate::scratch;
@ -375,24 +375,26 @@ fn twist(f: f32, subdiv: usize) -> Rule {
vertex( 0.5, 0.0, 0.5),
vertex(-0.5, 0.0, 0.5),
], &xf);
let seed_sub = util::subdivide_cycle(&seed, subdiv);
//let seed_sub = util::subdivide_cycle(&seed, subdiv);
let dx0: f32 = 2.0;
let dy: f32 = 0.1/f;
let ang: f32 = 0.1/f;
let count: usize = 4;
let n = seed_sub.len();
// Quarter-turn in radians:
let qtr = std::f32::consts::FRAC_PI_2;
let y = Vector3::y_axis();
let incr = geometry::Translation3::new(-dx0, 0.0, 0.0).to_homogeneous() *
let incr_inner = geometry::Translation3::new(-dx0, 0.0, 0.0).to_homogeneous() *
geometry::Rotation3::from_axis_angle(&y, ang).to_homogeneous() *
geometry::Translation3::new(dx0, dy, 0.0).to_homogeneous();
let incr_outer = geometry::Translation3::new(-dx0*2.0, 0.0, 0.0).to_homogeneous() *
geometry::Rotation3::from_axis_angle(&y, ang/2.0).to_homogeneous() *
geometry::Translation3::new(dx0*2.0, dy, 0.0).to_homogeneous();
let seed_orig = transform(&seed, &incr);
let seed_orig = transform(&seed, &incr_inner);
let seed_sub = util::subdivide_cycle(&seed_orig, subdiv);
let n = seed_sub.len();
let geom = OpenMesh {
verts: seed_sub.clone(),
@ -403,42 +405,56 @@ fn twist(f: f32, subdiv: usize) -> Rule {
verts: vec![vc],
faces: faces.clone(),
};
let recur = move |self_: Rc<Rule>| -> RuleEval {
// TODO: Why clone geometry here if I just have to clone it
// later on? Seems like Rc may be much easier (if I can't
// borrow directly - which is probably the case).
RuleEval {
geom: geom.clone(),
final_geom: final_geom.clone(),
children: vec![
Child {
rule: self_.clone(),
xf: incr,
vmap: (0..n).collect(),
},
],
}
let recur = move |incr: Mat4| -> RuleFn {
let c = move |self_: Rc<Rule>| -> RuleEval {
// TODO: Why clone geometry here if I just have to clone it
// later on? Seems like Rc may be much easier (if I can't
// borrow directly - which is probably the case).
RuleEval {
geom: geom.clone(),
final_geom: final_geom.clone(),
children: vec![
Child {
rule: self_.clone(),
xf: incr,
vmap: (0..n).collect(),
},
],
}
};
Box::new(c)
};
// TODO: so there's incr_inner & incr_outer that I wanted to
// parametrize over. why is it so ugly to do so?
let start = move |self_: Rc<Rule>| -> RuleEval {
let xform = |i| {
let xform = |dx, i| {
(geometry::Rotation3::from_axis_angle(&y, qtr * (i as f32)).to_homogeneous() *
geometry::Translation3::new(dx0, 0.0, 0.0).to_homogeneous())
geometry::Translation3::new(dx, 0.0, 0.0).to_homogeneous())
};
// First generate 'count' children, each one shifted/rotated
// differently:
let children: Vec<Child> = (0..count).map(|i| {
let xf = xform(i);
let children_inner = (0..count).map(|i| {
Child {
rule: Rc::new(Rule { eval: Box::new(recur.clone()) }),
xf: xf,
rule: Rc::new(Rule { eval: (recur.clone())(incr_inner) }),
xf: xform(dx0, i),
vmap: ((n+1)*i..(n+1)*(i+count)).collect(), // N.B.
// note n+1, not n. the +1 is for the centroid below
}
}).collect();
});
let children_outer = (0..count).map(|i| {
Child {
rule: Rc::new(Rule { eval: (recur.clone())(incr_outer) }),
xf: xform(dx0*2.0, i),
vmap: ((n+1)*i..(n+1)*(i+count)).collect(), // N.B.
// note n+1, not n. the +1 is for the centroid below
}
});
let children: Vec<Child> = children_inner.chain(children_outer).collect();
// Use byproducts of this to make 'count' copies of 'seed' with
// this same transform:

9
src/openmesh.rs
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@ -3,6 +3,7 @@
use nalgebra::*;
use std::fs::OpenOptions;
use std::io;
use std::borrow::Borrow;
/// A type for mesh vertices. Initialize with [vertex][self::vertex].
pub type Vertex = Vector4<f32>;
@ -44,11 +45,15 @@ pub struct OpenMesh {
impl OpenMesh {
pub fn append<T: IntoIterator<Item = OpenMesh>>(meshes: T) -> OpenMesh
pub fn append<T, U>(meshes: T) -> OpenMesh
where U: Borrow<OpenMesh>,
T: IntoIterator<Item = U>
{
let mut v: Vec<Vertex> = vec![];
let mut f: Vec<Tag> = vec![];
for mesh in meshes {
for mesh_ in meshes {
let mesh = mesh_.borrow();
// Position in 'verts' at which we're appending
// mesh.verts, which we need to know to shift indices:
let offset = v.len();

4
src/rule.rs
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@ -2,13 +2,15 @@ use crate::openmesh::{OpenMesh, Tag, Mat4};
//use crate::prim;
use std::rc::Rc;
pub type RuleFn = Box<dyn Fn(Rc<Rule>) -> RuleEval>;
/// Definition of a rule. In general, a `Rule`:
///
/// - produces geometry when it is evaluated
/// - tells what other rules to invoke, and what to do with their
/// geometry
pub struct Rule {
pub eval: Box<dyn Fn(Rc<Rule>) -> RuleEval>,
pub eval: RuleFn,
}
// TODO: It may be possible to have just a 'static' rule that requires
// no function call.