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Support calculating normals for indexed meshes (#11654)

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# Objective

- Finish #3987

## Solution

- Rebase and fix typo.

Co-authored-by: Robert Bragg <robert@sixbynine.org>
This commit is contained in:
Tygyh 2024-03-25 20:09:24 +01:00 committed by GitHub
parent 4f20faaa43
commit e9343b052f
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GPG key ID: B5690EEEBB952194
2 changed files with 54 additions and 23 deletions
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14
crates/bevy_gltf/src/loader.rs
View file

@ -476,18 +476,10 @@ async fn load_gltf<'a, 'b, 'c>(
if mesh.attribute(Mesh::ATTRIBUTE_NORMAL).is_none()
&& matches!(mesh.primitive_topology(), PrimitiveTopology::TriangleList)
{
let vertex_count_before = mesh.count_vertices();
mesh.duplicate_vertices();
bevy_utils::tracing::debug!(
"Automatically calculating missing vertex normals for geometry."
);
mesh.compute_flat_normals();
let vertex_count_after = mesh.count_vertices();
if vertex_count_before != vertex_count_after {
bevy_utils::tracing::debug!("Missing vertex normals in indexed geometry, computing them as flat. Vertex count increased from {} to {}", vertex_count_before, vertex_count_after);
} else {
bevy_utils::tracing::debug!(
"Missing vertex normals in indexed geometry, computing them as flat."
);
}
}
if let Some(vertex_attribute) = reader

63
crates/bevy_render/src/mesh/mesh/mod.rs
View file

@ -544,12 +544,13 @@ impl Mesh {
/// Calculates the [`Mesh::ATTRIBUTE_NORMAL`] of a mesh.
///
/// # Panics
/// Panics if [`Indices`] are set or [`Mesh::ATTRIBUTE_POSITION`] is not of type `float3` or
/// if the mesh has any other topology than [`PrimitiveTopology::TriangleList`].
/// Consider calling [`Mesh::duplicate_vertices`] or export your mesh with normal attributes.
/// Panics if [`Mesh::ATTRIBUTE_POSITION`] is not of type `float3`.
/// Panics if the mesh has any other topology than [`PrimitiveTopology::TriangleList`].
///
/// FIXME: The should handle more cases since this is called as a part of gltf
/// mesh loading where we can't really blame users for loading meshes that might
/// not conform to the limitations here!
pub fn compute_flat_normals(&mut self) {
assert!(self.indices().is_none(), "`compute_flat_normals` can't work on indexed geometry. Consider calling `Mesh::duplicate_vertices`.");
assert!(
matches!(self.primitive_topology, PrimitiveTopology::TriangleList),
"`compute_flat_normals` can only work on `TriangleList`s"
@ -561,18 +562,56 @@ impl Mesh {
.as_float3()
.expect("`Mesh::ATTRIBUTE_POSITION` vertex attributes should be of type `float3`");
let normals: Vec<_> = positions
.chunks_exact(3)
.map(|p| face_normal(p[0], p[1], p[2]))
.flat_map(|normal| [normal; 3])
.collect();
match self.indices() {
Some(indices) => {
let mut count: usize = 0;
let mut corners = [0_usize; 3];
let mut normals = vec![[0.0f32; 3]; positions.len()];
let mut adjacency_counts = vec![0_usize; positions.len()];
self.insert_attribute(Mesh::ATTRIBUTE_NORMAL, normals);
for i in indices.iter() {
corners[count % 3] = i;
count += 1;
if count % 3 == 0 {
let normal = face_normal(
positions[corners[0]],
positions[corners[1]],
positions[corners[2]],
);
for corner in corners {
normals[corner] =
(Vec3::from(normal) + Vec3::from(normals[corner])).into();
adjacency_counts[corner] += 1;
}
}
}
// average (smooth) normals for shared vertices...
// TODO: support different methods of weighting the average
for i in 0..normals.len() {
let count = adjacency_counts[i];
if count > 0 {
normals[i] = (Vec3::from(normals[i]) / (count as f32)).normalize().into();
}
}
self.insert_attribute(Mesh::ATTRIBUTE_NORMAL, normals);
}
None => {
let normals: Vec<_> = positions
.chunks_exact(3)
.map(|p| face_normal(p[0], p[1], p[2]))
.flat_map(|normal| [normal; 3])
.collect();
self.insert_attribute(Mesh::ATTRIBUTE_NORMAL, normals);
}
}
}
/// Consumes the mesh and returns a mesh with calculated [`Mesh::ATTRIBUTE_NORMAL`].
///
/// (Alternatively, you can use [`Mesh::compute_flat_normals`] to mutate an existing mesh in-place)
/// (Alternatively, you can use [`Mesh::with_computed_flat_normals`] to mutate an existing mesh in-place)
///
/// # Panics
/// Panics if [`Indices`] are set or [`Mesh::ATTRIBUTE_POSITION`] is not of type `float3` or