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use crate::{Axis, AxisPermutation, SignedAxis, UnorientedQuad};
use ilattice::glam::{IVec3, UVec3};
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub struct OrientedBlockFace {
pub(crate) n_sign: i32,
pub(crate) permutation: AxisPermutation,
pub(crate) n: UVec3,
pub(crate) u: UVec3,
pub(crate) v: UVec3,
}
impl OrientedBlockFace {
pub const fn new(n_sign: i32, permutation: AxisPermutation) -> Self {
let [n_axis, u_axis, v_axis] = permutation.axes();
Self {
n_sign,
permutation,
n: n_axis.get_unit_vector(),
u: u_axis.get_unit_vector(),
v: v_axis.get_unit_vector(),
}
}
pub fn canonical(normal: SignedAxis) -> Self {
Self::new(
normal.signum(),
AxisPermutation::even_with_normal_axis(normal.unsigned_axis()),
)
}
#[inline]
pub fn signed_normal(&self) -> IVec3 {
self.n.as_ivec3() * self.n_sign
}
#[inline]
pub fn quad_corners(&self, quad: &UnorientedQuad) -> [UVec3; 4] {
let w_vec = self.u * quad.width;
let h_vec = self.v * quad.height;
let minu_minv = if self.n_sign > 0 {
UVec3::from(quad.minimum) + self.n
} else {
UVec3::from(quad.minimum)
};
let maxu_minv = minu_minv + w_vec;
let minu_maxv = minu_minv + h_vec;
let maxu_maxv = minu_minv + w_vec + h_vec;
[minu_minv, maxu_minv, minu_maxv, maxu_maxv]
}
#[inline]
pub fn quad_mesh_positions(&self, quad: &UnorientedQuad, voxel_size: f32) -> [[f32; 3]; 4] {
self.quad_corners(quad)
.map(|c| (voxel_size * c.as_vec3()).to_array())
}
#[inline]
pub fn quad_mesh_normals(&self) -> [[f32; 3]; 4] {
[self.signed_normal().as_vec3().to_array(); 4]
}
#[inline]
pub fn quad_mesh_indices(&self, start: u32) -> [u32; 6] {
quad_indices(start, self.n_sign * self.permutation.sign() > 0)
}
#[inline]
pub fn tex_coords(
&self,
u_flip_face: Axis,
flip_v: bool,
quad: &UnorientedQuad,
) -> [[f32; 2]; 4] {
let face_normal_axis = self.permutation.axes()[0];
let flip_u = if self.n_sign < 0 {
u_flip_face != face_normal_axis
} else {
u_flip_face == face_normal_axis
};
match (flip_u, flip_v) {
(false, false) => [
[0.0, 0.0],
[quad.width as f32, 0.0],
[0.0, quad.height as f32],
[quad.width as f32, quad.height as f32],
],
(true, false) => [
[quad.width as f32, 0.0],
[0.0, 0.0],
[quad.width as f32, quad.height as f32],
[0.0, quad.height as f32],
],
(false, true) => [
[0.0, quad.height as f32],
[quad.width as f32, quad.height as f32],
[0.0, 0.0],
[quad.width as f32, 0.0],
],
(true, true) => [
[quad.width as f32, quad.height as f32],
[0.0, quad.height as f32],
[quad.width as f32, 0.0],
[0.0, 0.0],
],
}
}
}
fn quad_indices(start: u32, counter_clockwise: bool) -> [u32; 6] {
if counter_clockwise {
[start, start + 1, start + 2, start + 1, start + 3, start + 2]
} else {
[start, start + 2, start + 1, start + 1, start + 2, start + 3]
}
}