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use na;
use na::{Pnt3, Pnt2};
use super::{TriMesh, IndexBuffer};
use math::{Point, Vect};
pub fn quad<P>(width: <P::Vect as Vect>::Scalar,
height: <P::Vect as Vect>::Scalar,
usubdivs: usize,
vsubdivs: usize)
-> TriMesh<P>
where P: Point {
let mut quad = unit_quad::<P>(usubdivs, vsubdivs);
let mut s = na::zero::<P::Vect>();
s[0] = width;
s[1] = height;
for i in 2 .. na::dim::<P::Vect>() {
s[i] = na::one();
}
quad.scale_by(&s);
quad
}
pub fn quad_with_vertices<P>(vertices: &[P], nhpoints: usize, nvpoints: usize) -> TriMesh<P>
where P: Point {
assert!(nhpoints > 1 && nvpoints > 1, "The number of points must be at least 2 in each dimension.");
let mut res = unit_quad::<P>(nhpoints - 1, nvpoints - 1);
for (dest, src) in res.coords.iter_mut().zip(vertices.iter()) {
*dest = src.clone();
}
res
}
pub fn unit_quad<P>(usubdivs: usize, vsubdivs: usize) -> TriMesh<P>
where P: Point {
assert!(usubdivs > 0 && vsubdivs > 0, "The number of subdivisions cannot be zero");
assert!(na::dim::<P::Vect>() >= 2);
let wstep = na::one::<<P::Vect as Vect>::Scalar>() / na::cast(usubdivs as f64);
let hstep = na::one::<<P::Vect as Vect>::Scalar>() / na::cast(vsubdivs as f64);
let cw = na::cast(0.5);
let ch = na::cast(0.5);
let mut vertices = Vec::new();
let mut normals = Vec::new();
let mut triangles = Vec::new();
let mut tex_coords = Vec::new();
for i in 0usize .. vsubdivs + 1 {
for j in 0usize .. usubdivs + 1 {
let ni: <P::Vect as Vect>::Scalar = na::cast(i as f64);
let nj: <P::Vect as Vect>::Scalar = na::cast(j as f64);
let mut v = na::orig::<P>();
v[0] = nj * wstep - cw;
v[1] = ni * hstep - ch;
vertices.push(v);
let _1 = na::one::<<P::Vect as Vect>::Scalar>();
tex_coords.push(Pnt2::new(_1 - nj * wstep, _1 - ni * hstep))
}
}
for _ in 0 .. (vsubdivs + 1) * (usubdivs + 1) {
let mut n = na::zero::<P::Vect>();
n[0] = na::one();
normals.push(n)
}
fn dl_triangle(i: u32, j: u32, ws: u32) -> Pnt3<u32> {
Pnt3::new((i + 1) * ws + j, i * ws + j, (i + 1) * ws + j + 1)
}
fn ur_triangle(i: u32, j: u32, ws: u32) -> Pnt3<u32> {
Pnt3::new(i * ws + j, i * ws + (j + 1), (i + 1) * ws + j + 1)
}
for i in 0usize .. vsubdivs {
for j in 0usize .. usubdivs {
triangles.push(dl_triangle(i as u32, j as u32, (usubdivs + 1) as u32));
triangles.push(ur_triangle(i as u32, j as u32, (usubdivs + 1) as u32));
}
}
TriMesh::new(vertices, Some(normals), Some(tex_coords), Some(IndexBuffer::Unified(triangles)))
}