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use super::utils;
use glamx::{Pose3, Vec2, Vec3};
use std::collections::HashMap;
/// Different representations of the index buffer.
#[derive(Clone, Debug, PartialEq)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
pub enum IndexBuffer {
/// The vertex, normal, and uvs share the same indices.
Unified(Vec<[u32; 3]>),
/// The vertex, normal, and uvs have different indices.
/// Each element is [[vertex_idx, normal_idx, uv_idx]; 3] for the 3 corners.
Split(Vec<[[u32; 3]; 3]>),
}
impl IndexBuffer {
/// Returns the unified index buffer data or fails.
#[inline]
pub fn unwrap_unified(self) -> Vec<[u32; 3]> {
match self {
IndexBuffer::Unified(b) => b,
_ => panic!("Unable to unwrap to an unified buffer."),
}
}
/// Returns the split index buffer data or fails.
#[inline]
pub fn unwrap_split(self) -> Vec<[[u32; 3]; 3]> {
match self {
IndexBuffer::Split(b) => b,
_ => panic!("Unable to unwrap to a split buffer."),
}
}
/// Returns the unified index buffer data or fails.
#[inline]
pub fn as_unified(&self) -> &[[u32; 3]] {
match self {
IndexBuffer::Unified(b) => b,
_ => panic!("Unable to unwrap to an unified buffer."),
}
}
/// Returns the split index buffer data or fails.
#[inline]
pub fn as_split(&self) -> &[[[u32; 3]; 3]] {
match self {
IndexBuffer::Split(b) => b,
_ => panic!("Unable to unwrap to a split buffer."),
}
}
}
#[derive(Clone, Debug, PartialEq)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
/// Geometric description of a mesh.
pub struct RenderMesh {
// TODO: those should *not* be public.
/// Coordinates of the mesh vertices.
pub coords: Vec<Vec3>,
/// Coordinates of the mesh normals.
pub normals: Option<Vec<Vec3>>,
/// Textures coordinates of the mesh.
pub uvs: Option<Vec<Vec2>>,
/// Index buffer of the mesh.
pub indices: IndexBuffer,
}
impl RenderMesh {
/// Creates a new `TriMesh`.
///
/// If no `indices` is provided, trivial, sequential indices are generated.
pub fn new(
coords: Vec<Vec3>,
normals: Option<Vec<Vec3>>,
uvs: Option<Vec<Vec2>>,
indices: Option<IndexBuffer>,
) -> RenderMesh {
// generate trivial indices
let idx = indices.unwrap_or_else(|| {
IndexBuffer::Unified(
(0..coords.len() / 3)
.map(|i| [i as u32 * 3, i as u32 * 3 + 1, i as u32 * 3 + 2])
.collect(),
)
});
RenderMesh {
coords,
normals,
uvs,
indices: idx,
}
}
/// Whether or not this triangle mesh has normals.
#[inline]
pub fn has_normals(&self) -> bool {
self.normals.is_some()
}
/// Whether or not this triangle mesh has texture coordinates.
#[inline]
pub fn has_uvs(&self) -> bool {
self.uvs.is_some()
}
/// Translates each vertex of this mesh.
#[inline]
pub fn translate_by(&mut self, t: Vec3) {
for c in self.coords.iter_mut() {
*c += t;
}
}
/// Transforms each vertex and rotates each normal of this mesh.
#[inline]
pub fn transform_by(&mut self, t: Pose3) {
for c in self.coords.iter_mut() {
*c = t * *c;
}
for n in self.normals.iter_mut() {
for n in n.iter_mut() {
*n = t.rotation * *n;
}
}
}
/// The number of triangles on this mesh.
#[inline]
pub fn num_triangles(&self) -> usize {
match self.indices {
IndexBuffer::Unified(ref idx) => idx.len(),
IndexBuffer::Split(ref idx) => idx.len(),
}
}
/// Returns only the vertex ids from the index buffer.
#[inline]
pub fn flat_indices(&self) -> Vec<u32> {
let mut res = Vec::with_capacity(self.num_triangles() * 3);
match self.indices {
IndexBuffer::Unified(ref idx) => {
for i in idx {
res.push(i[0]);
res.push(i[1]);
res.push(i[2]);
}
}
IndexBuffer::Split(ref idx) => {
for i in idx {
res.push(i[0][0]);
res.push(i[1][0]);
res.push(i[2][0]);
}
}
}
res
}
}
impl RenderMesh {
/// Recomputes the mesh normals using its vertex coordinates and adjacency information
/// inferred from the index buffer.
#[inline]
pub fn recompute_normals(&mut self) {
let mut new_normals = Vec::new();
match self.indices {
IndexBuffer::Unified(ref idx) => {
utils::compute_normals(&self.coords[..], &idx[..], &mut new_normals);
}
IndexBuffer::Split(ref idx) => {
// XXX: too bad we have to reconstruct the index buffer here.
// The utils::recompute_normals function should be generic wrt. the index buffer
// type (it could use an iterator instead).
let coord_idx: Vec<[u32; 3]> =
idx.iter().map(|t| [t[0][0], t[1][0], t[2][0]]).collect();
utils::compute_normals(&self.coords[..], &coord_idx[..], &mut new_normals);
}
}
self.normals = Some(new_normals);
}
/// Flips all the normals of this mesh.
#[inline]
pub fn flip_normals(&mut self) {
if let Some(ref mut normals) = self.normals {
for n in normals {
*n = -*n
}
}
}
/// Flips the orientation of every triangle of this mesh.
#[inline]
pub fn flip_triangles(&mut self) {
match self.indices {
IndexBuffer::Unified(ref mut idx) => {
for i in idx {
i.swap(1, 2);
}
}
IndexBuffer::Split(ref mut idx) => {
for i in idx {
i.swap(1, 2);
}
}
}
}
/// Scales each vertex of this mesh.
///
/// For non-uniform scaling, normals are transformed by the inverse of the scale factors
/// and then renormalized to remain perpendicular to the scaled surface.
#[inline]
pub fn scale_by(&mut self, s: Vec3) {
for c in self.coords.iter_mut() {
*c *= s;
}
// Transform normals by inverse transpose of scale matrix.
// For diagonal scale S = diag(sx, sy, sz), inverse transpose is diag(1/sx, 1/sy, 1/sz).
if let Some(ref mut normals) = self.normals {
let inv_scale = Vec3::new(1.0 / s.x, 1.0 / s.y, 1.0 / s.z);
for n in normals.iter_mut() {
*n *= inv_scale;
*n = n.normalize();
}
}
}
}
impl RenderMesh {
/// Scales each vertex of this mesh.
#[inline]
pub fn scale_by_scalar(&mut self, s: f32) {
for c in self.coords.iter_mut() {
*c *= s
}
}
}
impl RenderMesh {
/// Force the mesh to use the same index for vertices, normals and uvs.
///
/// This might cause the duplication of some vertices, normals and uvs.
/// Use this method to transform the mesh data to a OpenGL-compliant format.
pub fn unify_index_buffer(&mut self) {
let new_indices = match self.indices {
IndexBuffer::Split(ref ids) => {
let mut vt2id: HashMap<[u32; 3], u32> = HashMap::default();
let mut resi: Vec<u32> = Vec::new();
let mut resc: Vec<Vec3> = Vec::new();
let mut resn: Option<Vec<Vec3>> = self.normals.as_ref().map(|_| Vec::new());
let mut resu: Option<Vec<Vec2>> = self.uvs.as_ref().map(|_| Vec::new());
for triangle in ids.iter() {
for point in triangle.iter() {
let idx = match vt2id.get(point) {
Some(i) => {
resi.push(*i);
None
}
None => {
let idx = resc.len() as u32;
resc.push(self.coords[point[0] as usize]);
let _ = resn.as_mut().map(|l| {
l.push(self.normals.as_ref().unwrap()[point[1] as usize])
});
let _ = resu
.as_mut()
.map(|l| l.push(self.uvs.as_ref().unwrap()[point[2] as usize]));
resi.push(idx);
Some(idx)
}
};
let _ = idx.map(|i| vt2id.insert(*point, i));
}
}
self.coords = resc;
self.normals = resn;
self.uvs = resu;
let mut batched_indices = Vec::new();
assert!(resi.len().is_multiple_of(3));
for f in resi[..].chunks(3) {
batched_indices.push([f[0], f[1], f[2]]);
}
Some(IndexBuffer::Unified(batched_indices))
}
_ => None,
};
let _ = new_indices.map(|nids| self.indices = nids);
}
/// Unifies the index buffer and ensure duplicate each vertex
/// are duplicated such that no two vertex entry of the index buffer
/// are equal.
pub fn replicate_vertices(&mut self) {
let mut resi: Vec<u32> = Vec::new();
let mut resc: Vec<Vec3> = Vec::new();
let mut resn: Option<Vec<Vec3>> = self.normals.as_ref().map(|_| Vec::new());
let mut resu: Option<Vec<Vec2>> = self.uvs.as_ref().map(|_| Vec::new());
match self.indices {
IndexBuffer::Split(ref ids) => {
for triangle in ids.iter() {
for point in triangle.iter() {
let idx = resc.len() as u32;
resc.push(self.coords[point[0] as usize]);
let _ = resn
.as_mut()
.map(|l| l.push(self.normals.as_ref().unwrap()[point[1] as usize]));
let _ = resu
.as_mut()
.map(|l| l.push(self.uvs.as_ref().unwrap()[point[2] as usize]));
resi.push(idx);
}
}
}
IndexBuffer::Unified(ref ids) => {
for triangle in ids.iter() {
for point in triangle.iter() {
let idx = resc.len() as u32;
resc.push(self.coords[*point as usize]);
let _ = resn
.as_mut()
.map(|l| l.push(self.normals.as_ref().unwrap()[*point as usize]));
let _ = resu
.as_mut()
.map(|l| l.push(self.uvs.as_ref().unwrap()[*point as usize]));
resi.push(idx);
}
}
}
};
self.coords = resc;
self.normals = resn;
self.uvs = resu;
let mut batched_indices = Vec::new();
assert!(resi.len().is_multiple_of(3));
for f in resi[..].chunks(3) {
batched_indices.push([f[0], f[1], f[2]]);
}
self.indices = IndexBuffer::Unified(batched_indices)
}
}
impl RenderMesh {
/// Forces the mesh to use a different index for the vertices, normals and uvs.
///
/// If `recover_topology` is true, this will merge exactly identical vertices together.
pub fn split_index_buffer(&mut self, recover_topology: bool) {
let new_indices = match self.indices {
IndexBuffer::Unified(ref ids) => {
let resi;
if recover_topology {
let (idx, coords) =
utils::split_index_buffer_and_recover_topology(&ids[..], &self.coords[..]);
self.coords = coords;
resi = idx;
} else {
resi = utils::split_index_buffer(&ids[..]);
}
Some(IndexBuffer::Split(resi))
}
_ => None,
};
let _ = new_indices.map(|nids| self.indices = nids);
}
}