use super::triangle3d;
use crate::{
mesh::{Indices, Mesh, MeshBuilder, Meshable},
render_asset::RenderAssetUsages,
};
use bevy_math::primitives::{Tetrahedron, Triangle3d};
use wgpu::PrimitiveTopology;
pub struct TetrahedronMeshBuilder {
tetrahedron: Tetrahedron,
}
impl MeshBuilder for TetrahedronMeshBuilder {
fn build(&self) -> Mesh {
let mut faces: Vec<_> = self.tetrahedron.faces().into();
if self.tetrahedron.signed_volume().is_sign_negative() {
faces.iter_mut().for_each(Triangle3d::reverse);
}
let mut positions = vec![];
let mut normals = vec![];
let mut uvs = vec![];
for face in faces {
positions.extend(face.vertices);
let face_normal = triangle3d::normal_vec(&face);
normals.extend(vec![face_normal; 3]);
let face_uvs = triangle3d::uv_coords(&face);
uvs.extend(face_uvs);
}
let indices = Indices::U32(vec![0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
Mesh::new(
PrimitiveTopology::TriangleList,
RenderAssetUsages::default(),
)
.with_inserted_indices(indices)
.with_inserted_attribute(Mesh::ATTRIBUTE_POSITION, positions)
.with_inserted_attribute(Mesh::ATTRIBUTE_NORMAL, normals)
.with_inserted_attribute(Mesh::ATTRIBUTE_UV_0, uvs)
}
}
impl Meshable for Tetrahedron {
type Output = TetrahedronMeshBuilder;
fn mesh(&self) -> Self::Output {
TetrahedronMeshBuilder { tetrahedron: *self }
}
}
impl From<Tetrahedron> for Mesh {
fn from(tetrahedron: Tetrahedron) -> Self {
tetrahedron.mesh().build()
}
}