coerce vector types of mesh

1 files changed, 24 insertions, 6 deletions

diff --git a/src/classes/mesh.rs b/src/classes/mesh.rs
index 348c61c..6d21ff5 100644
--- a/src/classes/mesh.rs
+++ b/src/classes/mesh.rs
@@ -182,16 +182,34 @@ impl VertexData {
     pub fn read_channel_vec<T: VectorType>(
         &self,
         channel: VertexDataChannel,
+        coerce: bool,
     ) -> Result<Option<Vec<T>>> {
-        let Some((dim, data)) = self.read_channel(channel) else {
+        let Some((dim, mut data)) = self.read_channel(channel) else {
             return Ok(None);
         };
         if dim != T::DIM {
-            bail!(
-                "dimension mismatch reading {channel:?} channel ({} != {})",
-                dim,
-                T::DIM
-            );
+            if coerce {
+                let mut ndata = Vec::new();
+                if dim > T::DIM {
+                    for e in data.chunks_exact(dim) {
+                        ndata.extend(&e[..T::DIM]);
+                    }
+                } else if dim < T::DIM {
+                    for e in data.chunks_exact(dim) {
+                        ndata.extend(e);
+                        for _ in 0..(T::DIM - dim) {
+                            ndata.push(0.);
+                        }
+                    }
+                }
+                data = ndata;
+            } else {
+                bail!(
+                    "dimension mismatch reading {channel:?} channel ({} != {})",
+                    dim,
+                    T::DIM
+                );
+            }
         }
         Ok(Some(VectorType::convert_array(data)))
     }