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|
use std::alloc::Layout;
use crate::vector::Vec3;
pub mod cube;
pub mod vertex_buffer;
pub const POSITION_VERTEX_ATTRIB_NAME: &str = "pos";
#[derive(Debug, Clone)]
pub struct Mesh
{
vertex_buf: vertex_buffer::VertexBuffer,
indices: Option<Vec<u32>>,
}
impl Mesh
{
pub fn builder() -> Builder
{
Builder::default()
}
pub fn vertex_buf(&self) -> &vertex_buffer::VertexBuffer
{
&self.vertex_buf
}
#[must_use]
pub fn indices(&self) -> Option<&[u32]>
{
self.indices.as_deref()
}
#[must_use]
pub fn indices_mut(&mut self) -> Option<&mut [u32]>
{
self.indices.as_deref_mut()
}
/// 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 pos_iter = self
.vertex_buf()
.iter::<[f32; 3]>(POSITION_VERTEX_ATTRIB_NAME)
.map(|vertex_pos| Vec3::from(*vertex_pos))
.into_iter();
let first_pos = pos_iter.next().unwrap();
pos_iter
.fold(
FurthestPosAcc {
up: FurthestPos::new(first_pos, &Vec3::UP),
down: FurthestPos::new(first_pos, &Vec3::DOWN),
left: FurthestPos::new(first_pos, &Vec3::LEFT),
right: FurthestPos::new(first_pos, &Vec3::RIGHT),
back: FurthestPos::new(first_pos, &Vec3::BACK),
front: FurthestPos::new(first_pos, &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()
}
}
/// Mesh builder
#[derive(Debug, Clone, Default)]
pub struct Builder
{
vertex_buf: vertex_buffer::VertexBuffer,
indices: Option<Vec<u32>>,
}
impl Builder
{
pub fn new() -> Self
{
Self::default()
}
pub fn vertices(mut self, vertices_bytes: vertex_buffer::VertexBuffer) -> Self
{
self.vertex_buf = vertices_bytes;
self
}
pub fn indices(mut self, indices: impl IntoIterator<Item = u32>) -> Self
{
self.indices = Some(indices.into_iter().collect());
self
}
pub fn build(self) -> Mesh
{
Mesh {
vertex_buf: self.vertex_buf,
indices: self.indices,
}
}
}
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
pub enum VertexAttrType
{
Float32,
Float32Array
{
length: usize,
},
}
impl VertexAttrType
{
pub fn layout(&self) -> Layout
{
match self {
Self::Float32 => Layout::new::<f32>(),
Self::Float32Array { length } => Layout::array::<f32>(*length).unwrap(),
}
}
}
#[derive(Debug, Clone)]
pub struct DirectionPositions
{
pub up: Vec3<f32>,
pub down: Vec3<f32>,
pub left: Vec3<f32>,
pub right: Vec3<f32>,
pub back: Vec3<f32>,
pub front: Vec3<f32>,
}
impl<'mesh> From<FurthestPosAcc<'mesh>> for DirectionPositions
{
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: Vec3<f32>,
dot_prod: f32,
direction: &'mesh Vec3<f32>,
}
impl<'mesh> FurthestPos<'mesh>
{
fn new(pos: Vec3<f32>, direction: &'mesh Vec3<f32>) -> Self
{
Self {
pos,
dot_prod: direction.dot(&pos),
direction,
}
}
fn update_if_further(&mut self, point: 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;
}
}
}
|
