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|
use ecs::Component;
use crate::vector::Vec3;
use crate::vertex::Vertex;
pub mod cube;
#[derive(Debug, Clone, Component)]
pub struct Mesh
{
vertices: Vec<Vertex>,
indices: Option<Vec<u32>>,
}
impl Mesh
{
#[must_use]
pub fn new(vertices: Vec<Vertex>, indices: Option<Vec<u32>>) -> Self
{
Self { vertices, indices }
}
#[must_use]
pub fn vertices(&self) -> &[Vertex]
{
&self.vertices
}
#[must_use]
pub fn indices(&self) -> Option<&[u32]>
{
self.indices.as_deref()
}
/// Finds the vertex positions that are furthest in every 3D direction. Keep in mind
/// that this can be quite time-expensive if the mesh has many vertices.
pub fn find_furthest_vertex_positions(&self) -> DirectionPositions<'_>
{
let mut point_iter = self.vertices().iter().map(|vertex| &vertex.pos).into_iter();
let first_point = point_iter.next().unwrap();
point_iter
.fold(
FurthestPosAcc {
up: FurthestPos::new(&first_point, &Vec3::UP),
down: FurthestPos::new(&first_point, &Vec3::DOWN),
left: FurthestPos::new(&first_point, &Vec3::LEFT),
right: FurthestPos::new(&first_point, &Vec3::RIGHT),
back: FurthestPos::new(&first_point, &Vec3::BACK),
front: FurthestPos::new(&first_point, &Vec3::FRONT),
},
|mut furthest_pos_acc, pos| {
furthest_pos_acc.up.update_if_further(pos);
furthest_pos_acc.down.update_if_further(pos);
furthest_pos_acc.left.update_if_further(pos);
furthest_pos_acc.right.update_if_further(pos);
furthest_pos_acc.back.update_if_further(pos);
furthest_pos_acc.front.update_if_further(pos);
furthest_pos_acc
},
)
.into()
}
}
#[derive(Debug, Clone)]
pub struct DirectionPositions<'mesh>
{
pub up: &'mesh Vec3<f32>,
pub down: &'mesh Vec3<f32>,
pub left: &'mesh Vec3<f32>,
pub right: &'mesh Vec3<f32>,
pub back: &'mesh Vec3<f32>,
pub front: &'mesh Vec3<f32>,
}
impl<'mesh> From<FurthestPosAcc<'mesh>> for DirectionPositions<'mesh>
{
fn from(acc: FurthestPosAcc<'mesh>) -> Self
{
Self {
up: acc.up.pos,
down: acc.down.pos,
left: acc.left.pos,
right: acc.right.pos,
back: acc.back.pos,
front: acc.front.pos,
}
}
}
#[derive(Debug)]
struct FurthestPosAcc<'mesh>
{
up: FurthestPos<'mesh>,
down: FurthestPos<'mesh>,
left: FurthestPos<'mesh>,
right: FurthestPos<'mesh>,
back: FurthestPos<'mesh>,
front: FurthestPos<'mesh>,
}
#[derive(Debug)]
struct FurthestPos<'mesh>
{
pos: &'mesh Vec3<f32>,
dot_prod: f32,
direction: &'mesh Vec3<f32>,
}
impl<'mesh> FurthestPos<'mesh>
{
fn new(pos: &'mesh Vec3<f32>, direction: &'mesh Vec3<f32>) -> Self
{
Self {
pos,
dot_prod: direction.dot(&pos),
direction,
}
}
fn update_if_further(&mut self, point: &'mesh Vec3<f32>)
{
let point_dot_prod = self.direction.dot(point);
if point_dot_prod > self.dot_prod {
self.pos = point;
self.dot_prod = point_dot_prod;
}
}
}
|
