fix point-projection on voxels with empty chunks (#384)

* fix point-projection on voxels with empty chunks

* chore: cargo fmt

* fix clippy

Author: sebcrozet

CHANGELOG.md

@@ -1,3 +1,7 @@
+## Unreleased
+
+- Fix point-projection of a ball on a voxels shape containing empty chunks (e.g. after voxels removal).
+
 ## 0.25.0
 
 - The `Voxels` shape now uses a sparse storage internally.

src/partitioning/bvh/bvh_optimize.rs

@@ -13,9 +13,9 @@ impl Bvh {
         let num_optimized_leaves = (num_leaves * TARGET_REBUILD_NODE_PERCENTAGE).div_ceil(100);
 
         let num_leaves_sqrt = (num_leaves as Real).sqrt();
-        let root_mode = if frame_index % 2 == 0 {
+        let root_mode = if frame_index.is_multiple_of(2) {
             RootOptimizationMode::Skip
-        } else if (frame_index / 2) % 16 == 0 {
+        } else if (frame_index / 2).is_multiple_of(16) {
             RootOptimizationMode::BreadthFirst
         } else {
             RootOptimizationMode::PriorityQueue

src/query/point/point_voxels.rs

@@ -1,4 +1,4 @@
-use crate::math::{Point, Real};
+use crate::math::{Point, Real, Vector};
 use crate::query::{PointProjection, PointQuery};
 use crate::shape::{Cuboid, FeatureId, Voxels, VoxelsChunkRef};
 
@@ -8,11 +8,15 @@ impl PointQuery for Voxels {
         self.chunk_bvh()
             .project_point(pt, Real::MAX, |chunk_id, _| {
                 let chunk = self.chunk_ref(chunk_id);
-                Some(chunk.project_local_point_and_get_vox_id(pt, solid).0)
+                chunk
+                    .project_local_point_and_get_vox_id(pt, solid)
+                    .map(|(proj, _)| proj)
             })
-            .unwrap()
-            .1
-             .1
+            .map(|res| res.1 .1)
+            .unwrap_or(PointProjection::new(
+                false,
+                Vector::repeat(Real::MAX).into(),
+            ))
     }
 
     #[inline]
@@ -23,13 +27,16 @@ impl PointQuery for Voxels {
         self.chunk_bvh()
             .project_point_and_get_feature(pt, Real::MAX, |chunk_id, _| {
                 let chunk = self.chunk_ref(chunk_id);
-                let (proj, vox) = chunk.project_local_point_and_get_vox_id(pt, false);
                 // TODO: we need a way to return both the voxel id, and the feature on the voxel.
-                Some((proj, FeatureId::Face(vox)))
+                chunk
+                    .project_local_point_and_get_vox_id(pt, false)
+                    .map(|(proj, vox)| (proj, FeatureId::Face(vox)))
             })
-            .unwrap()
-            .1
-             .1
+            .map(|res| res.1 .1)
+            .unwrap_or((
+                PointProjection::new(false, Vector::repeat(Real::MAX).into()),
+                FeatureId::Unknown,
+            ))
     }
 }
 
@@ -39,7 +46,7 @@ impl<'a> VoxelsChunkRef<'a> {
         &self,
         pt: &Point<Real>,
         solid: bool,
-    ) -> (PointProjection, u32) {
+    ) -> Option<(PointProjection, u32)> {
         // TODO: optimize this naive implementation that just iterates on all the voxels
         //       from this chunk.
         let base_cuboid = Cuboid::new(self.parent.voxel_size() / 2.0);
@@ -59,6 +66,6 @@ impl<'a> VoxelsChunkRef<'a> {
             }
         }
 
-        (result, result_vox_id as u32)
+        (smallest_dist < Real::MAX).then_some((result, result_vox_id as u32))
     }
 }

src/shape/voxels/voxels_chunk.rs

@@ -180,7 +180,7 @@ impl<'a> VoxelsChunkRef<'a> {
 
     /// Iterates through all the voxels in this chunk.
     ///
-    /// Note that this yields both empty and non-empty voxels within the range. This does not
+    /// Note that this only yields non-empty voxels within the range. This does not
     /// include any voxel that falls outside [`Self::domain`].
     pub fn voxels(&self) -> impl Iterator<Item = VoxelData> + '_ {
         let range = self.domain();
@@ -189,7 +189,7 @@ impl<'a> VoxelsChunkRef<'a> {
 
     /// Iterate through the data of all the voxels within the given (semi-open) voxel grid indices.
     ///
-    /// Note that this yields both empty and non-empty voxels within the range. This does not
+    /// Note that this only yields non-empty voxels within the range. This does not
     /// include any voxel that falls outside [`Self::domain`].
     #[cfg(feature = "dim2")]
     pub fn voxels_in_range(

src/utils/median.rs

@@ -13,7 +13,7 @@ pub fn median(vals: &mut [Real]) -> Real {
 
     let n = vals.len();
 
-    if n % 2 == 0 {
+    if n.is_multiple_of(2) {
         (vals[n / 2 - 1] + vals[n / 2]) / na::convert::<f64, Real>(2.0)
     } else {
         vals[n / 2]